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Fraser
2006-Nov-06, 08:58 PM
It's all relative. How many times have you heard that? Well, when you're traveling close to the speed of light, everything really is relative; especially the passage of time. ...

Read the full blog entry (http://www.astronomycast.com/uncategorized/einsteins-theory-of-special-relativity/)

KimB
2006-Nov-06, 10:00 PM
If you travel to the nearest star (which is 4 llight years away) at the speed of light It would take 4 years. But is that 4 years ship time or 4 years for someone on the earth assuming you could know instantly when they had got there?

Tensor
2006-Nov-07, 03:30 AM
If you travel to the nearest star (which is 4 llight years away) at the speed of light It would take 4 years. But is that 4 years ship time or 4 years for someone on the earth assuming you could know instantly when they had got there?

4 years for someone on earth. Travelling at c, the ship would experience no time for the trip (this assumes there is no acceleration or deceleration time, getting to and stopping from c.)

KimB
2006-Nov-07, 10:36 AM
So, for the ship travelling 4 light years zero time speed is infinite... So doesn't that break the 'rule' that you can't travel faster than the speed of light?

From the ship the earth is travelling (receding) at the speed of light... so no time passes there either (from the ship point of view). So when the ship gets to the star no time has passed on the earth???? (Now I'm confused.) Or is this another example of the lights on the train coming on at different times depending on your location.

Kim

Tensor
2006-Nov-07, 12:34 PM
So, for the ship travelling 4 light years zero time speed is infinite... So doesn't that break the 'rule' that you can't travel faster than the speed of light?

I didn't say infinite. Notice I also said you would have to ignore acceleration and deceleration time. Travelling at c, there will be no time elapsed for the ship, 4 years for earth.

From the ship the earth is travelling (receding) at the speed of light... so no time passes there either (from the ship point of view). So when the ship gets to the star no time has passed on the earth????

From the ship's point of view, that is correct. No time has passed. From the earth's point of view, 4 years have passed.

(Now I'm confused.)

Don't feel bad, it can be quite confusing. Relativity has quite a few subtle aspects that are very counter intuitive. As a result, there is a lot of confusion concerning some of those aspects. This is one of them.

Or is this another example of the lights on the train coming on at different times depending on your location.Kim

Well, it's not quite the same thing, but both of them are a consequence of relativity.

Sticks
2006-Nov-07, 06:21 PM
At one point you were being drowned out by some background music. Anychance you can hold off on the music until you have finished?

Tensor
2006-Nov-07, 06:25 PM
At one point you were being drowned out by some background music. Anychance you can hold off on the music until you have finished?

Huh?:confused:

Sticks
2006-Nov-07, 06:47 PM
Huh?:confused:

The podcast from 23:24 to 24:16

It sounded like someone thought they had finished when they put the backing track on. It added nothing to the programme

KimB
2006-Nov-07, 06:47 PM
I'm still a bit confused.

I'll try to clarify my first question. Ignoring acceleration the ship is travelling at C. Time has slowed to a stop. Speed is measured in distance travelled in a given time (e.g. m/s). But travelling at C time stops, therefore the distance travelled (d) in a unit of time is infinite, d/0 (from the ship point of view). Star trek here I come. But I thought Einstein's theory excludes infinite speed?

Maybe considering the return journey will help me understand what's going on.

Let's say the spaceship is approaching earth now at C. Inside the spaceship there are no windows. The Ship is travelling at a constant velocity. Under these conditions, wouldn't it be impossible to tell if you were even moving let alone travelling at the speed of light?

Now say from the ship, you could only see the earth. You couldn't tell if you were approaching the earth at C or the earth was approaching you at C. (Assuming you'd have time to think about it) If you can't tell the difference between these two scenarios, wouldn't it look from the ship like time on the earth was standing still and time on the ship was normal? But if this is true then the journey for the ship must take some amount time.

what I'm trying to understand is a rule that works regardless of where you are. If that's possible.

Thanks

Kim

Fazor
2006-Nov-07, 07:04 PM
If you were traveling the speed of light, what would you see? wouldn't you and your ship be invisible to you, as you would be moving away from the light from that time frame at the same speed as it's traveling towards you? hmm...

trinitree88
2006-Nov-07, 09:59 PM
If you were traveling the speed of light, what would you see? wouldn't you and your ship be invisible to you, as you would be moving away from the light from that time frame at the same speed as it's traveling towards you? hmm...

Fazor...for a speed boat, it's a water wave wake....for you it's a black hole. Seems to be a lot easier than aggregating sufficient mass in one place to create one. However, you have an if-then syllogism predicated on the fact that you...a material being in a supposedly material ship...are already traveling at the SR -forbidden velocity of c. Einstein spent a while thinking about your scenario. Pete.

eric_marsh
2006-Nov-28, 01:10 AM
For the most part the ToR makes sense to me. There is one thing that I've not quite got a good grasp on. Perhaps someone can explain it to me. Might even be a good question for a Q&A podcast. Here goes:

We have two actors, Jerry and Jeri. Jeri gets onto a really fast motorcycle - naw better make that a space ship and accelerates away from Jerry. As Jerry observes Jeri, Jeri seems to be moving in slow motion as time is moving more slowly for her from Jerry's perspective. So what does Jeri see when she looks back at Jerry? It seems to me that she sees the exact same thing that Jerry saw looking at her, that is to say that from her perspective Jerry is moving very slowly because relative to her he is accelerating away.

Is this correct and does it make sense? After all, this is relativity, that is to say that everything is relative to the observer.

luckynate
2007-Jan-02, 07:41 PM
I'll try to clarify my first question. Ignoring acceleration the ship is travelling at C. Time has slowed to a stop. Speed is measured in distance travelled in a given time (e.g. m/s). But travelling at C time stops, therefore the distance travelled (d) in a unit of time is infinite, d/0 (from the ship point of view).

okay KIMB here we go.
einsteins thinking about light speed motion is thus. The motion through space is totally relative to the observer(am i leaving earth or is earth leaving me?)
So yes, the earth would appear to stand still from the vantage of the ship moving at C (the Cship). However, from the earth's vantage, the crew of the Cship would appear frozen in time.
To each observer, however, their own time would remain CONSTANT and unnaffected, much in the way that you never notice time fluctuations here on earth despite our high velocity motions and accelerations through space(although they never even come close to the Cship's speed).

The reason for this effect is that as we move through spacetime, our velocity is divided up between the 4 dimensions (up-down, left-right, back-forth, past-future) and all the motion through space is deflected away from the motion through time. So if ALL the motion is dedicated to moving through space, there will be none left over to move through time.
The easiest way to understand it is to say that A BEAM OF LIGHT NEVER GROWS OLDER, hence the relative sense of "now" is relevant even when looking far into spacetime to the distant past. We see the sun there now, but really for the sun that was 8 minutes ago.

luckynate
2007-Jan-02, 07:47 PM
If you were traveling the speed of light, what would you see? wouldn't you and your ship be invisible to you, as you would be moving away from the light from that time frame at the same speed as it's traveling towards you? hmm...

:think: No dude, thats the relative part of relativity, light would move away from your ship and or body at light speed compared to your motion and position....you cant beat light in a race (or even keep up) no matter how fast you go, so you would notice NO difference unless you looked OUTSIDE your ship. Everything behind you would appear frozen in time though, so that's pretty cool I guess.

squid
2007-Jan-08, 10:43 PM
Going back to KimB's question, if it takes 4 years for a photon to travel that distance, why doesn't it take the ship 4 years to travel that same distance? Wouldn't the ship act like a ridiculously huge photon? And being a part of that ridiculously huge photon why wouldn't you feel the passage of those four years?
And I don't understand--Why is time stopping just because you are moving at the speed of light?

luckynate
2007-Jan-14, 08:37 AM
if it takes 4 years for a photon to travel that distance, why doesn't it take the ship 4 years to travel that same distance? Wouldn't the ship act like a ridiculously huge photon? And being a part of that ridiculously huge photon why wouldn't you feel the passage of those four years?
And I don't understand--Why is time stopping just because you are moving at the speed of light?
Ok this is hard to explain but here's why, time and space are part of the SAME THING. moving through space IS moving through time. This effect is caused by the maximum speed limit of 'c', or the speed of light. The speed of light can also be called the speed of time. The reason for this is that two different observers viewing the same event from different locations will not be able to agree on the time at which it happened.
Imagine a fireworks expert, who has two rockets (pointed away from each other like a 'V') that can be seen from a long distance away.If he lights both rockets at the same time, what will happen? Well, if you are EQUALLY distant from two explosions (as the engineer would be) you would see them go off simultaneously. However, an observer closer to one exploding rocket then the other will first see the one closest to him go off, and only later see the other. From the point of view of the fireworks engineer who lit the rockets, they both flew apart the same distance an went off at the same time. but from the viewpont of someone closer to one explosion the further one happened later in time. This would also be true no matter which rocket you are closer to, so two observers close to opposite rockets will both claim that theirs went off first. Which one is right? Both, thats the wierd part.

when you 'move' close to the speed of light a similiar type of effect is percieved. Both the person 'moving' close to the speed of light and the "stationary" observer will claim that the other's watch is slowing down more and more as light speed gets closer. ('stationary' and 'moving' are words that can be used interchangeably, i.e. Is the astronaut moving away from earth or is earth moving away from the astronaut? again, Both is the correct response) so time does NOT in fact stop FOR YOU when moving close to light speed, but rather , everything outside appears stopped from your viewpoint, and other people looking your way would see that YOU appear frozen in time from their viewpoint... That's the relative part of relativity.
Achieving light speed motion is not actually possible, but the time compression is observed thusly. As you move closer and closer to the speed of light, the distance gets shorter and shorter, even for the same trip. So going from here to the moon would be 400,000 km going at the speeds you and i are used to, but at 98% of light speed the trip would be much shorter in distance, maybe only a few hundred km, and thats why time slows when you go fast. If you could reach light speed all distances shrink to Zero size, no matter how far. That why you get there the same time you left(frozen time).

spent
2007-Feb-15, 04:48 AM
I'm not buying that. Even if it was Einstein. Guy was smart but........

If we had a clock that tells years. And some do. And we put it abord the
new horizons space craft ( and it returned to earth), I'm putting my
money on it taking 18 years for it to get to pluto and (from our perspective)
and the clock aboard also saying 18 years had past.

Even if it's traveling faster than we are. I'm betting the ship will not look
brand spanking new either. And pretty much out of fuel. All of which take time.

So .............

At the speed of light. No matter what the speed is. Change it to whatever you want.
(If we could change it). One year is still one year. To us and the ship. The ship would be either Farther or not as far. That's it.

If not new horizons would be at pluto ( from it's perspective in less than nine years). But for us it would take nine years?

So ..............

Did the new horizons space craft take pictures of the Jupiter flyby even if to us it hadn't got there yet?

Then again. Who's to say nothing can travel faster than the speed of light?
Light is just the fastest thing we know of now. Then again how do we know light even travels. Maybe it just spreads or expands. Have we captured a light particle? or a light wave? or both (photon). What does it look like?

Space itself could be light that just isn't bright but dark. And its spreading causing all of the red shift as it pulls the objects away from all the other objects just as a
rubber duck gets pulled down stream by a water current. But because it was accelerated in the beginning it continues to accelerate until some other force stops it or decelerates it making it a constant speed or slower. Maybe that's why farther object appear to moving away faster than nearer objects.

Always wanted to get that out.

I still think the universe is infinitely large AND small.

Every smaller particle is made up of smaller particles and ever Larger particle is made up of smaller particles. Infinitely ......................................

Space either ends and something is encapsulating it or space is infinite.
But..................

Then the space encapsulating space itself either ends or is infinite as well.
And so on. And so on.

Now. If "Infinite" is not possible. Then there is a "REALLY GOOD" chance that "WE" do not even exist. "WE" just think "We" do.

We may. When we die. Just see it all as a dream that was interactive.

ok. Man I'm really scaring myself now. He....He.....He..........

=)

I got to stop now. Sorry.

clint
2007-May-31, 11:38 PM
There is one explanation in the show that I just don't understand:
the theory behind the experiment with the perpendicular mirrors where they found out that the speed of light is constant (in the late 1800s I think)

It's a bit hard to explain,
so let me start with that image of the ball, thrown on a moving boat:

If you throw a ball against a wall on a moving boat, and along the movement vector of the boat, someone on the shore in the same line of the movement vector of the boat, would see the ball move faster on the way to the wall (speed of the ball plus speed of the boat), and slower on its way ricocheting back from the wall (speed of the ball minus speed of the boat).

Pretty straightforward, no problem so far.

Now, if you throw the ball sideways (perpendicular to the movement vector of the boat),
both you and the observer on the shore would see it moving at the exact same speed, both on its way to the wall and back, right?

So far so good.

However, an observer on the same boat with you
would ALWAYS see the ball moving at the exact same speed,
no matter what direction you throw it in, right?

Since you AND the observer are both moving on the same boat, in the exact same direction and at the exact same speed, the movement of the boat would not at all affect the observed speed of the ball.

So ONLY someone standing on the shore would observe a difference in the speed of the thrown ball, and ONLY if it is NOT thrown perpendicular to the movement vector of the boat.

RIGHT?

Now back to the experiment with the perpendicular mirrors:
- the light is the ball thrown at the wall
- the mirrors are the walls
(one in the line of movement of the earth, the other perpendicular)
- the earth is the moving boat

But hey, all the observers are also on that moving boat (Earth),
so the speed of the ball (light) shouldn't be affected,
no matter what direction it is thrown in.

Where is the 'independent' observer on the shore???
Only a observer who is NOT on the same boat (earth) should observe any difference, RIGHT?

So the fact that both light beams in that experiment traveled at the same speed, does not prove anything, does it???

Sorry, this is a bit long, but I just can't figure it out... :wall:
Can anybody help me?! :confused:

Tensor
2007-Jun-01, 02:51 AM
There is one explanation in the show that I just don't understand:
the theory behind the experiment with the perpendicular mirrors where they found out that the speed of light is constant (in the late 1800s I think)

You have a slight misunderstanding of the reason for the experiment, and this may be why you are having trouble with this. At the time of the experiment, most physicists thought that light was made up of waves (it is now thought that EM radiation has both wave and particle aspects). The question was, what was waving. It was postulated that there was a medium and this medium was given the name "luminiferous aether".
The experiment was an attempt to measure some of the properties of this aether. The reason for the perpendicular mirrors was one arm would measure the length of time each arm, traveling either with or against the motion of the aether past the earth. The other arm would not be moving either with or against the aether and it was thought that when the two light beams were brought together, there should be a shift of the interference patterns, indicating the different travel times. The mirrors could be rotated so the arms could measure the different shifts based on the rotation of the Earth, along with the expected differences due to the Earth's orbit around the Sun.
As a result of the set up, the different paths should produce different travel times and this would show up as the shift of the interference pattern. The problem was, there wasn't any kind of shift at all (within the errors of measurement). There were serveral possible reasons for this, one, was the Earth was dragging the aether with it as the Earth moved. Another possible reason was the Earth, was, in fact, motionless. Another, possibility was that the speed of light would measure a constant speed, no matter what speed the test equipment was moving.
Most of the possible reasons for the non shift would produce some kind of other observational effects, that weren't observed. In 1905 Einstein publish his Special Theory, in which he postulated that the speed of light was constant in all inertial frames of reference, along with the postulate that all laws of physics are the same in every inertial frame of reference.

With just those two postulates, Einstein publish "On the Electrodynamics of Moving Bodies" (http://www.fourmilab.ch/etexts/einstein/specrel/www/), which introduced SR. As you can see, the postulate that the speed of light was constant in all inertial frames of reference explains the reason for not finding any fringe shifts in the MM experiment. Coupled with the discovery that EM waves are transverse and don't need a medium, pretty much killed off aether (there continue to be some die hards who don't accept SR, and thus they keep looking for an aether or some other way to explain the observations and tests, without the need for SR.

John Mendenhall
2007-Jun-01, 07:22 PM
Now, if you throw the ball sideways (perpendicular to the movement vector of the boat),
both you and the observer on the shore would see it moving at the exact same speed, both on its way to the wall and back, right.

No, the observer on the shore will see the ball as moving faster, because the course of the ball to him is the vector sum of the boat's forward speed and the speed of the ball perpendicular to boat's motion.

This is covered very well in one of the introductory texts on special relativity, and I'll go look it up and post the title. For light, where the observer on the boat and the observer on the shore must measure the same velocity, the clocks on the boat must run slower.

Got it, the book is "Special Relativity" by A.P. French, and it is excellent. You can memorize his examples and astonish your friends.

EvilEye
2007-Jun-01, 08:33 PM
(as stated before) Forget Acceleration on either end of the trip.

At lightspeed, you would climb into the ship.... hit the "go" button and instantaneously arrive at your destination.

This is where the movie "Contact" had it completely backward.

Yes.. they used "wormholes' but the same principal was in effect. (I think)

More time should have passed for the people waiting for Dr. Arroway... not the other way around.

John Mendenhall
2007-Jun-01, 09:48 PM
As you move closer and closer to the speed of light, the distance gets shorter and shorter, even for the same trip. So going from here to the moon would be 400,000 km going at the speeds you and i are used to, but at 98% of light speed the trip would be much shorter in distance, maybe only a few hundred km, and thats why time slows when you go fast. If you could reach light speed all distances shrink to Zero size, no matter how far. That why you get there the same time you left(frozen time).

You sure? Math backup?

EvilEye
2007-Jun-01, 10:59 PM
I think luckynate got confused with "perception".

On the ship you would percieve time as "normal" and that would make the distance seem very short.

damian1727
2007-Jun-03, 10:50 AM
I'm not buying that. Even if it was Einstein. Guy was smart but........
.

gotta love that

i like the thought that as light arrives at the same time it leaves :)
this must mean light recognises no distance
but i find it intresting that altho here and there are the same place if you are light i can tell if its here or there .......... *cough cough*:sick::sick:

inertia is a ***** as well:cry::cry::confused::confused:

damian1727
2007-Jun-03, 10:52 AM
oops

damian1727
2007-Jun-04, 03:18 PM
You sure? Math backup?

yup as wierd as it seems..... known as

Lorentz transformation (?lör?ens ?tranz·f?r?m?·sh?n)
(mathematics) Any linear transformation of euclidean four space which preserves the quadratic form q(x,y,z,t) = t2-x2-y2-z2.
(relativity) Any of the family of mathematical transformations used in the special theory of relativity to relate the space and time variables of different Lorentz frames.

http://www-groups.dcs.st-and.ac.uk/~history/Mathematicians/Lorentz.html

Lorentz is also famed for his work on the FitzGerald-Lorentz contraction, which is a contraction in the length of an object at relativistic speeds. Lorentz transformations, which he introduced in 1904, form the basis of Einstein's special theory of relativity. They describe the increase of mass, the shortening of length, and the time dilation of a body moving at speeds close to the velocity of light.

?

as i understand it the spaceship gets shorter !!:surprised

jets get a bit (tiny bit) shorter when going fast..

jamini
2007-Jun-05, 05:44 PM
?

as i understand it the spaceship gets shorter !!:surprised

jets get a bit (tiny bit) shorter when going fast..

It would be more correct to say that distances appear to contract relative to the observer, while moving at velocities close to the speed of light. ;)

.

Anton
2007-Jun-05, 09:13 PM
as i understand it the spaceship gets shorter !!:surprised

jets get a bit (tiny bit) shorter when going fast..

Jamini is right. Nothing gets shorter or heavier beacause it moves at speeds approaching the speed of light. It just appears to and that's weird enough...

To the external observer, the spaceship might appear contracted whereas the astronaut on board would realize that everything is normal.

To the astronaut the distance to the moon might appear to be very short while the external observer will realize that the moon is where it always used to be!

damian1727
2007-Jun-05, 11:09 PM
err if u say so :hand:

Tensor
2007-Jun-06, 12:49 AM
The appearance of a contraction is a artifact of the simplifying done to explain it. Most of the time, the explanation is only presented in one dimension. One dimensionally, the object would appear, to an observer, to contract. Realistically, if you were able to view an actual three demensional object traveling relativistically, it would appear to be rotated, not contracted. This is due to the combination of the speed and the different light paths from the front and rear of the object to the observer. "Spacetime Physics" by Wheeler and Taylor (http://www.amazon.com/Spacetime-Physics-Edwin-F-Taylor/dp/0716723271/ref=pd_bbs_1/002-0350473-8004036?ie=UTF8&s=books&qid=1181090785&sr=1-1), has an excellent explanation of the effect.

EvilEye
2007-Jun-08, 08:22 PM
Oh... and if you were traveling near the speed of light.... everything around you would appear in your forward vision. You would see almost all 360 degrees directly in front of the ship.

It would be very confusing to navigate that way.

damian1727
2007-Jun-09, 04:00 PM
wow

would that be a similar view to that i would get looking up from the event horizon of a black hole?

Lil Grasshoppah
2007-Jun-11, 04:37 PM
would that be a similar view to that i would get looking up from the event horizon of a black hole?

Someone unfortunate enough to be just inside the event horizon of a black hole would see the universe looking perfectly normal. Hostile - lots of really bad radiation rushing inward - but otherwise normal. From the outside. the event horizon is a bizarre interface where in-falling material seems to get "stuck," slowly disintegrating until it can no longer be seen. From the point of view of an object falling in, there is no obvious difference between being on one side or the other (until said object attempts to exit the vicinity, of course).

John Mendenhall
2007-Jun-11, 05:55 PM
yup as wierd as it seems..... known as

Lorentz transformation (?lör?ens ?tranz·f?r?m?·sh?n)
(mathematics) Any linear transformation of euclidean four space which preserves the quadratic form q(x,y,z,t) = t2-x2-y2-z2.
(relativity) Any of the family of mathematical transformations used in the special theory of relativity to relate the space and time variables of different Lorentz frames.

http://www-groups.dcs.st-and.ac.uk/~history/Mathematicians/Lorentz.html

Lorentz is also famed for his work on the FitzGerald-Lorentz contraction, which is a contraction in the length of an object at relativistic speeds. Lorentz transformations, which he introduced in 1904, form the basis of Einstein's special theory of relativity. They describe the increase of mass, the shortening of length, and the time dilation of a body moving at speeds close to the velocity of light.

?

as i understand it the spaceship gets shorter !!:surprised

jets get a bit (tiny bit) shorter when going fast..

That's his biography, not the relevant math. Hang on, I'll look it up.

Ok. after plowing through the Wiki SR article, to the observer on the starship the distances to destinations appear to shrink, because the observer's clocks are running slow. It is as if the star in front of the ship, and the intervening space in front of the star (and the space behind the star), was all moving toward the ship at a high fraction of fthe speed of alight and was length contracted. Neat idea.

damian1727
2007-Jun-12, 08:07 AM

damian1727
2007-Jun-12, 08:11 AM
where as 4 the observer space does not contract but the ship does !! lol

:lol:

my theory is that it takes particals a bit longer to work out where they are in relation to everything when moving fast or in large numbers so they have to slow down a bit :shifty::shifty:

John Mendenhall
2007-Jun-12, 02:27 PM
where as 4 the observer space does not contract but the ship does !! lol

:lol:

my theory is that it takes particals a bit longer to work out where they are in relation to everything when moving fast or in large numbers so they have to slow down a bit :shifty::shifty:

For which observer?

To the external observer, the starship is length contracted. To the observer on the starship, the starship is not length contracted, because his meter stick is also length contracted in the direction of motion just enough so that when he measures the length of the starship in the direction of motion, it has not changed. The interesting things occur as he travels to the destination star in what to him is a very short time, because his clocks are running slow.

Jerry
2007-Jun-12, 02:57 PM
Let's do the time warp again...

I have been trying - for years now - to determine what would happen if the 'Ether' is truly a function of mass, not a change in clock speed. One of the results is that light would travel faster in inter galactic space. But how much faster, and what controls the velocity? I don't have good answers, but the fact that greater gravitational lensing is observed that is predicted (and interpreted as a dark matter effect) could also be a 'no matter' effect -- a slightly greater velocity of light.

EvilEye
2007-Jun-13, 01:25 AM
I would tend to think that there is no limit to the speed of light with nothing to restrict it. But when time is a factor, it becomes a line.

That sounds confusing.

If a photon was going its speed in the universe unhindered, and experienced a "nothingness" it would instantly be at the "other side".

You can't therefore guage its speed.

I think gravity, and time work the same way.

That being... if you take out everything (anything) in between.. the effect is right there.

If there is nothing between the light source and the destination, the distance in null.

EvilEye
2007-Jun-13, 01:31 AM
Without editing my previous statement, I want to say when I speak of gravity... I mean mass.

With No mass of any kind... and no electric charge, there can be no force. And therefore no space...which leads to no time.

There would be nothing to traverse.

Tensor
2007-Jun-13, 05:16 PM
Without editing my previous statement, I want to say when I speak of gravity... I mean mass.

When you say mass, do you mean energy? In GR, it's energy that causes the warping of space-time. The amount of energy in a given amount of mass can be found by using E = mc2.

EvilEye
2007-Jun-13, 07:41 PM
When you say mass, do you mean energy? In GR, it's energy that causes the warping of space-time. The amount of energy in a given amount of mass can be found by using E = mc2.

I'm not sure. Don't we have energetic particals that have no mass?

damian1727
2007-Jun-14, 11:13 PM
If a photon was going its speed in the universe unhindered, and experienced a "nothingness" it would instantly be at the "other side".

You can't therefore guage its speed.
.

is that not the way it is ? ie if time stops at c then the photon is instantly at the other side ?

i guess we live in a fractured fallen shadow of the real world where light lives:confused::confused::confused:

EvilEye
2007-Jun-17, 03:00 PM
is that not the way it is ? ie if time stops at c then the photon is instantly at the other side ?

i guess we live in a fractured fallen shadow of the real world where light lives:confused::confused::confused:

My best guess would be "yes".

If we lived at light-speed, we would live all of our entire life at one instant.

hhEb09'1
2007-Jun-17, 03:06 PM
This is where the movie "Contact" had it completely backward.

Yes.. they used "wormholes' but the same principal was in effect. (I think)
No, it's not in effect. The wormhole idea was developed for Sagan by Kip Thorne (I think that's who is credited). The idea is a sort of a bridge between two points of spacetime.

If we lived at light-speed, we would live all of our entire life at one instant.The question is, whose instant? :)

damian1727
2007-Jun-17, 11:17 PM
lol if there is no time at c then there can only be one instance!!!

mine!!!

one love....

Kamikaze762x39
2007-Aug-17, 09:00 AM
As to seeing the ship frozen in time... This is hard to grasp for the following reasons:

The ship starts out a minimum set distance from earth in space. Lets just say this point provides an instantaneous image for our viewing pleasure.

At this motionless state, it is emitting a constant light image of the craft which is traveling at roughly 300,000 km/s. The coordinates of the ship is the source point for all the light providing this image.

The ship kicks into light speed, ignoring acceleration time.

One second later, the ship is 300,000km away, and the object that was providing the image is no longer present in the same spot.

The light once provided by the image must reach us and then change relative to the ship's motion. How can the ship appear frozen in time if it is no longer present?

If the ship away from us at 300,000 km/s and light moves toward us at 300,000 km/s, we should experience a time dialation, but we will still see the object receeding.

Consider a fighter plane moving away at 500 m/s and firing missiles aft at 500m/s every one second, just as the ship/light traveling at indentical speeds in opposite directions.

1s - 1st missile position 500m
2s - 1st missile position on target, 2nd missile postion 1000m
3s - 2nd missile position 500m, 3rd missile postion 1500m
4s - 2nd missile position on target, 3rd 1000 m, 4th 2000 m

1X ->

2X- ->

3X - ->

4X- - ->

5X - - ->

Missiles arrive every 2 seconds even though they were fired every one second.

Now given an infinite number of frames of course with actual light and ship, but would this not be the way it happens? Wouldn't we see the light of ship in 1/2 time elapsed and not frozen?

Kamikaze762x39
2007-Aug-17, 09:14 AM
This is the same reason I don't understand the description of the event horizon of a black hole. Sure, the light would be suspended there, but since it is trapped and frozen, the light can't reach our eyes. As to the slow-moving light infinitely escaping the point just before the event horizon, it is also receeding and diminishing infinitely. The object gets trashed and compacted but leaves it's signature behind in the event horizon. The output image has to get fractionally reduced in brightness and clarity forever until it is undetectable and negligible. Nothing can duplicate energy from nothing, and recreating an image from a non-existant object violates multiple laws of physics.

RussT
2007-Aug-18, 01:44 AM
4 years for someone on earth. Travelling at c, the ship would experience no time for the trip (this assumes there is no acceleration or deceleration time, getting to and stopping from c.)

And even when you state it in its most extreme case you cannot see that it is PURE Sci-Fi :confused:

Time does NOT stop just because something is traveling at "c" ;)

Everything is 'Relative', including a single photon traveling at "c".

Even though that single photon has 0 velocity, in its own frame, for every 186,000 miles it travels, 1 second of Time passes.

And this whole thing shows the absolute falicy in defining light in 'its own reference frame' as having 0 velocity, because that winds up defining the whole path of light from its source to its sink as "Instantaneous", which is "Impossible", even in its own frame!

EvilEye
2007-Aug-22, 08:43 PM
Even though that single photon has 0 velocity, in its own frame, for every 186,000 miles it travels, 1 second of Time passes.

But that is from an observer's perspective. Not the photon's.

For the photon (or ship) the trip was instantaneous.

It wouldn't know that 1 second has passed (in a 186,000 mile trip) until it arrived and found out related to the welcoming party. ;)

Imagine instead of a ship...a magical doorway. You walk through and are instantly somewhere else across the solar system where your twin is waiting.

For you.... but not for your twin. They are older than you are when you get there.

RussT
2007-Aug-23, 01:28 AM
But that is from an observer's perspective. Not the photon's.

For the photon (or ship) the trip was instantaneous.

It wouldn't know that 1 second has passed (in a 186,000 mile trip) until it arrived and found out related to the welcoming party. ;)

Imagine instead of a ship...a magical doorway. You walk through and are instantly somewhere else across the solar system where your twin is waiting.

For you.... but not for your twin. They are older than you are when you get there.

SO, how do they/you justify that light from differing distant sources, even in the frame of the light paths taken, straight line if no massive body curves it, goes from the source to us "Instananeously"?

In other words, the light that is emitted from say Alpha Centauri gets here instantaneously just like the light from a Quasar 13 billion light Yr's away?

Sitting in my chair typing this, I am 'at rest'/0 velocity in numerous frames. 0 velocity in the earths rotation frame, 0 velocity as earth is traveling around the sun, 0 velocity as our solar system is traveling around the Milky way, BUT Time goes by one second at a time.

I am certainly NOT arriving at any distance in any of those frames instantly, and time is always relative to what reference frame you are measuring it against...1 day for me to go 1 revolution around as the earth rotates in that frame, even though I have 0 velocity sitting in my chair...1 year for earth to go around the sun,,ETC ETC.

Each individual photon is no different than me in my chair.

Even in the frame of light traveling at "c", Instantaneous travel from point A to point B at any distance is Impossible!!!

Your "Magic Door" is exactly the right terminology..."Magic".

It is equivilent to the analogy of a 'worm hole' bending space to such a degree that two points are in the same place at the same time.

jonfr
2007-Aug-23, 08:21 AM
As I see it, light speed is not the fasted speed ever. Given the fact that there are partial that already travel faster then speed of light. To travel faster then light, special methods are needed.

I know this sounds bit loose, but I am figuring out how to say it so it can be understand properly.

RussT
2007-Aug-23, 09:10 AM
Given the fact that there are partial that already travel faster then speed of light.

I am not aware of any such 'fact'.

What is a 'partial'?

hhEb09'1
2007-Aug-23, 09:45 AM
I am not aware of any such 'fact'.

What is a 'partial'?Particle, surely, but the theoretical particles that go faster than light (tachyons ?) aren't a fact, I don't think. "Despite a recent raft of reports in the media..." (http://physicsworld.com/cws/article/print/482)

Grey
2007-Aug-23, 03:00 PM
Even in the frame of light traveling at "c", Instantaneous travel from point A to point B at any distance is Impossible!!!Actually, it's important to note that in special relativity, a reference frame moving at the speed of light relative to another reference frame is not actually valid. There just is no such thing. Yes, you can sort of bend the rules and say, "well, if this were a valid reference frame, then time would stand still", but that's a big "if". There is no such thing as the rest frame of a photon. No matter what valid reference frame you choose in relativity, light always moves relative to that frame at the same speed, c. So it's actually meaningless to talk about what a clock might measure if it were travelling along in the rest frame of a photon, because it's not physically possible for a clock of any sort to do so. So, you're right here, I think (in that it doesn't make sense to talk about how a photon behaves in its "rest frame"), but not quite for the reasons that you think you are. :)

RussT
2007-Aug-24, 05:27 AM
Actually, it's important to note that in special relativity, a reference frame moving at the speed of light relative to another reference frame is not actually valid. There just is no such thing. Yes, you can sort of bend the rules and say, "well, if this were a valid reference frame, then time would stand still", but that's a big "if". There is no such thing as the rest frame of a photon. No matter what valid reference frame you choose in relativity, light always moves relative to that frame at the same speed, c. So it's actually meaningless to talk about what a clock might measure if it were travelling along in the rest frame of a photon, because it's not physically possible for a clock of any sort to do so. So, you're right here, I think (in that it doesn't make sense to talk about how a photon behaves in its "rest frame"), but not quite for the reasons that you think you are. :)

SO, how do they/you justify that light from differing distant sources, even in the frame of the light paths taken, straight line if no massive body curves it, goes from the source to us "Instananeously"?

In other words, the light that is emitted from say Alpha Centauri gets here instantaneously just like the light from a Quasar 13 billion light Yr's away?

So Grey, how have you been able to justify or ignore this?

Grey
2007-Aug-24, 03:58 PM
So Grey, how have you been able to justify or ignore this?Because it's not true. There is no valid relativistic reference frame in which light gets from any point to any other point instantaneously. In every valid reference frame, light (when travelling through a vacuum) travels at the same finite speed, and so there will be a measurable amount of time between its emission and absorption.

EvilEye
2007-Aug-24, 09:07 PM
Because it's not true. There is no valid relativistic reference frame in which light gets from any point to any other point instantaneously. In every valid reference frame, light (when travelling through a vacuum) travels at the same finite speed, and so there will be a measurable amount of time between its emission and absorption.

But NOT measurable by the photon's perspective. It is instantaneous for the photon.. not for the person measuring it.

I still can't get pastthe fact that time stops at the speed of light. And if c is c, then c is c, and for the photon the trip is instant. It has not aged.

jrysk
2007-Aug-24, 11:23 PM
Special Relativity/The interpretation of special relativity
From Wikibooks, the open-content textbooks collection
< Special Relativity
Special Relativity

 Geometrical interpretation

 Natural mathematics, Einstein's "practical geometry" and the Ryskamp objection of "natural" coincidence
Note that the metrical interpretation of the 1905 paper disguises, but does not avoid, the "natural" coincidence of points M' and M ("fallt zwar...zusammen") which Einstein, following the program of natural mathematics which he had adopted from Poincare's SCIENCE AND HYPOTHESIS (1902), put in the train experiment in his book RELATIVITY (1916). This work receives little attention from scholars because it is regarded as a popularization. However, Einstein valued it highly and recently it has been claimed as the clearest exposition of the relativity of simultaneity--of "practical geometry," which was Einstein's term for natural mathematics.

Previously, Einstein's devotion to "practical geometry" was regarded as problematic in relation to relativity, because it could not be seen precisely where it operated in the mechanics of special relativity. John Ryskamp's contribution was to explicate this operation, in the course of which he drew a fundamental objection. Although RELATIVITY had been around for upwards of ninety years, he was the first commentator to draw attention to "natural" coincidence as THE application par excellence of "practical geometry," in "Paradox, Natural Mathematics, Relativity and Twentieth-Century Ideas" (May 19, 2007). Available at SSRN: http://ssrn.com/abstract=897085. See also the Discussion section for this issue. This paper also lodged a "natural" coincidence objection against many fundamental theories, and claimed that it invalidates the Pythagorean theorem--although to date he has not indicated where "natural" coincidence is lodged in any given proof of the Pythagorean theorem.

Here is the crucial passage from the paper (pp. 13-14):

Consider this passage from Lawson’s accurate translation of Einstein’s Relativity:

Are two events (e.g. the two strokes of lightning A and B) which are simultaneous with reference to the railway embankment also simultaneous relatively to the train? We shall show directly that the answer must be in the negative. When we say that the lightning strokes A and B are simultaneous with respect to be embankment, we mean: the rays of light emitted at the places A and B, where the lightning occurs, meet each other at the mid-point M of the length AB of the embankment. But the events A and B also correspond to positions A and B on the train. Let M1 be the mid-point of the distance AB on the traveling train. Just when the flashes (as judged from the embankment) of lightning occur, this point M1 naturally coincides with the point M but it moves…with the velocity…of the train.

This passage is by now so familiar that we think there can be nothing new to be seen in it. But there is: it is the term, “naturally coincides.” This term (“fällt zwar…zusammen” in the German) leaps out at us because we are looking at it with twenty-first century eyes, not twentieth-century eyes; indeed, perhaps the most difficult cultural task now before us is simply to realize that we are not living in the twentieth century.

“Natural” coincidence is otherwise known as a spacetime point. Einstein has already spent twenty-odd pages of this very brief book laying out the assumptions which underlie the train experiment. He is very careful about being consistent with them, and he is a devoted and very strict Euclidean. But Einstein was not, it appears, quite careful enough. We know that he is assuming, along with Euclid, that the definition of the coincidence of two points is a point. However, we have never gotten (and never get, in any of Einstein’s writings) a definition of a “natural” coincidence of two points. This alone prevents us from going on and this argument, which defined the twentieth century, abruptly ends. We also have a problem if we try to resolve the issue ourselves. If we simply drop the term “naturally” we run into a situation in which Einstein has told us to assume two Cartesian coordinate systems, but now leaves us with one, since, following from the definition of the coincidence of two points, if two parallel coordinate systems coincide at one point, they coincide at all points and are one coordinate system, not two. We have been led to a contradiction.

Ryskamp's idea that the presence of "natural" coincidence disproves the theory, is new among the many lodged against special relativity over the decades. Remarkably, and unlike other objections, it disputes NONE of the hypotheses, assumptions or principles of special relativity--the way critics of relativity previously proceeded. This is because, in Ryskamp's view, natural mathematics imports ideas into arguments which have no logical relation to any part of the argument: according to the point of view of natural mathematics, this must be done. At the same time, if it is recognized that that is what is going on in any given natural mathematics argument, it leads us to wonder where this importation has occurred.

Ryskamp's accomplishment seems to be, to have definitively located such an importation into relativity. According to natural mathematicians, this is no great accomplishment, because such importations must occur. However, it is mortifying for advocates of relativity who feel relativity has been proved, because Ryskamp's objection is, if an accurate description of what is going on in the relativistic argument, manifestly and incontestably a disproof of relativity. According to natural mathematics itself, there are no grounds on which to contest it, which makes it the most alarming of all comments on relativity.

The physics community has found it extremely difficult to deal with the Ryskamp objection, apparently because physicists themselves have a natural mathematics point of view. They are now trying to disentangle themselves from this point of view, but it is proving to be a monumental task due to the mountainous physics terminology built on the foundation of "natural" coincidence. It is not surprising, then, that the objection has not yet been overcome by any commentator, no matter how high up in the physics hierarchy. At the very least, the objection has had two consequences: first, it anchors Einstein firmly within the natural mathematics polemic. Second, it clarifies other objections which, while not on point, are now evaluated as more or less unfocussed warnings that there may be something wrong with the geometry of special relativity. As the new mathematics historiography proceeds, more embarrassing material on the terms of natural mathematics is being revealed: it can now hardly be said to be a point of view; it is more akin to a religion or a cult. No scientist wants to be seen as partaking of any such doctrine.

Among the other contentions of Ryskamp's paper, he claims that Einstein, as a devotee of natural mathematics, could NOT have sought, in formulating relativity, to make relativity internally consistent, because it is the position of natural mathematics that arguments with a program of internal consistency lead invariably to paradox. While commentators had long noted problematic aspects of Einstein's argumentation, the universal approach to relativity was that Einstein had at least intended to make it internally consistent. Ryskamp contends that this was never the case, which if true would mean that an entirely different approach has to be taken to relativity. Indeed, it may be that Einstein's 1921 lecture, "Geometry and Experience," in which he used the phrase "practical geometry," constitutes Einstein's summary of the degree of refinement to which he was able, in RELATIVITY (1916), to bring his expression of natural mathematics.

Approaching relativity as an argument which was never intended to be internally consistent--an eye-opening approach, to say the least--and identifying "natural" coincidence by applying that approach, emerges from a recent trend in the historiography of physics: to examine a facet of Einstein's work which has not traditionally been examined in isolation--his rhetorical approach. Historians of physics have recently become much more sensitive to Einstein as a textual architect--an "artful" writer, as one commentator puts it--and the role this may play in evaluating the logic of special relativity. This would seem to be in order: if relativity was never intended to be internally consistent, then unification is a misdirected project based on a faulty understanding of relativity.

This approach is at the heart of two recent works: Don Howard and John Stachel, eds., EINSTEIN: THE FORMATIVE YEARS (2000) and Thomas Ryckman, THE REIGN OF RELATIVITY (2005). The approach is an attempt to break out of an apparent dead end in quantum electrodynamics by looking to see if new insights of a synthetic nature could be gleaned from the historical record. As Ryckman points out, terms coined decades ago are still used even by advanced physicists in order to frame and present physics research--without any consideration that such terms may be themselves problematic or incorporate problematic notions in relativity.

A recent phenomenon, historical perspective is finally being brought to bear on the early career of relativity. Ryskamp's own approach is novel and entirely unexpected: through the history of set theory. The result is that readers may now approach Einstein's work with the idea that it may need to be regarded as dated, as an historical anachronism addressed to a past audience which shared Einstein's general intellectual approach--closer, argument for argument, to Newton than to contemporary understanding. At the very least, the Ryskamp objection is waving a big red flag of caution.

RussT
2007-Aug-26, 12:16 AM
Because it's not true. There is no valid relativistic reference frame in which light gets from any point to any other point instantaneously. In every valid reference frame, light (when travelling through a vacuum) travels at the same finite speed, and so there will be a measurable amount of time between its emission and absorption.

And yet Tensor said...
http://www.bautforum.com/861168-post3.html
[4 years for someone on earth. Travelling at c, the ship would experience no time for the trip (this assumes there is no acceleration or deceleration time, getting to and stopping from c.)]

And this 0 time for the astronauts would be true according to SR, regardless of how far (Alpha Centauri or the Quasar 13 billion Ly's away) the 'other star' they would be traveling to was away ;)

Those "Counter Intuitive"..."That's relativity for ya'" have been trying to tell you something all along ;)

SO, when I asked how you 'justify' or 'ignore' this...you chose 'Ignore' ;)

For the Frozen Time scenario, you questioned that with a big "IF", BUT for the instantaneous part, you did choose 'ignore' by just defining the frame as 'invalid', be defining photons in their own frame as 'having no rest frame'...[There is no such thing as the rest frame of a photon.].

BUT, each individual photon is at rest, just sitting there, at 0 velocity, traveling at "c", just as I am sitting here in my chair typing this, at 0 velocity in numerous reference frames.

NOW, how do I determine anything from my 0 velocity 'rest frame'?

Everything coming to my "Now" is delayed. so to determine anything that is not right in front of my senses, eyes, ears, we have a thing called Time which involves measuring distance. So, the first thing we do to determine time, is go to the reference frame of the rotating earth.

We have 24 hours for one rotation of the earth which gives us our standard for Time.

SO, I cannot Measure anything "REAL" from my 0 velocity 'rest frame'. I MUST go to whatever reference frame I wish to measure, and determine 'what is really happening there', to obtain my sense of 'reality'

To obtain my sense of reality for what a year is, I must measure from my 'rest frame', how long it takes for earth to go around the sun...in other words, we are always using the 'other frame' for our sense of what is real.

When Einstein did his 'thought experiments', by defining photons as 'having no rest frame', and using SCI-FI spaceships traveling at near "c", and all the way to "c", he started using the 0 velocity 'rest frame' to determine reality. And THEN the 'time dilation', Lorentz contraction, etc, just compensates to make 'that reality' mathematically consistent.

hhEb09'1
2007-Aug-26, 12:33 PM
Those "Counter Intuitive"..."That's relativity for ya'" have been trying to tell you something all along You appear to be advocating an Against The Mainstream position, is that correct?

EvilEye
2007-Aug-26, 12:47 PM
I was just listening again to "Questions" #5 episode, and Pamela herself stated that photons experience NO time. - even though they are moving.

If it is against the mainstream then we'll have to ban Fraser and Pamela. ;)

hhEb09'1
2007-Aug-26, 02:08 PM
I was just listening again to "Questions" #5 episode, and Pamela herself stated that photons experience NO time. - even though they are moving.

If it is against the mainstream then we'll have to ban Fraser and Pamela. I was referring to RussT's position--I think he'd disagree with Pamela there. But it seems to go beyond that. I'm not sure.

EvilEye
2007-Aug-26, 05:22 PM
All good with me as long as I learn something.

RussT
2007-Aug-27, 08:14 AM
I was just listening again to "Questions" #5 episode, and Pamela herself stated that photons experience NO time. - even though they are moving.

If it is against the mainstream then we'll have to ban Fraser and Pamela. ;)

Which Grey responded to with a BIG "IF"...the No Time part

[then time would stand still", but that's a big "if"]

John Mendenhall
2007-Aug-27, 04:46 PM
The appearance of a contraction is a artifact of the simplifying done to explain it. Most of the time, the explanation is only presented in one dimension. One dimensionally, the object would appear, to an observer, to contract. Realistically, if you were able to view an actual three demensional object traveling relativistically, it would appear to be rotated, not contracted. This is due to the combination of the speed and the different light paths from the front and rear of the object to the observer. "Spacetime Physics" by Wheeler and Taylor (http://www.amazon.com/Spacetime-Physics-Edwin-F-Taylor/dp/0716723271/ref=pd_bbs_1/002-0350473-8004036?ie=UTF8&s=books&qid=1181090785&sr=1-1), has an excellent explanation of the effect.

I agree, that's the way I understand it. Perhaps Richard could comment on this.

Thanks for the reference on rotation.

Grey
2007-Aug-27, 06:21 PM
But NOT measurable by the photon's perspective. It is instantaneous for the photon.. not for the person measuring it.

I still can't get pastthe fact that time stops at the speed of light. And if c is c, then c is c, and for the photon the trip is instant. It has not aged.I'd disagree, and simply state that the question of how much time passes in the "rest frame of the photon" is not a meaningful one within relativity. In any valid relativistic reference frame, light moves at c, so there's no such thing as the rest frame of a photon. Now, as I said, one can bend relativity a bit, and try to use it to answer the question, "well, what if it were a valid reference frame, how much time would pass?" And it's true that a certain reading of the equations would tell you that no time had passed. But you'd also find that some of the relativistic equations would now include division by zero, so that should be a big clue that you shouldn't take your results too seriously. :) It's certainly true that there's no way to measure how much time elapses between emission and absorption for a photon, but that's at least as much because there's no way for a clock of any sort to travel along with a photon as because "no time passes".

Grey
2007-Aug-27, 06:44 PM
And yet Tensor said...
http://www.bautforum.com/861168-post3.html
[4 years for someone on earth. Travelling at c, the ship would experience no time for the trip (this assumes there is no acceleration or deceleration time, getting to and stopping from c.)]Tensor's pretty bright. I'd assume that he's aware that it's not really possible to accelerate instantaneously to the speed of light. But his statement gets most of the idea across. A more precise wording might be that if you travel from here to Alpha Centauri, moving at arbitrarily close to the speed of light, the trip will take roughly four years for outside observers, but will be arbitrarily short for the person travelling. Depending on how fast you go, the trip could take a year as measured by the traveller, or a day, or a second, or a nanosecond. Essentially no time as measured by an outside observer, if the traveller is moving quickly enough. And it still scales. If you're travelling fast enough that time dilation means you measure a nanosecond to go four light years, then it will take you a whole second to travel four billion light years.

As always, don't take a casual statement attempting to explain the general idea of a theory to someone as the theory itself. If you want to know how differently moving observers will measure time according to special relativity, you need to look at the math of special relativity. And if you want to address problems that you think exist within special relativity, you definitely need to be looking at the math itself.

SO, when I asked how you 'justify' or 'ignore' this...you chose 'Ignore' ;)Well, I'm not "ignoring" some blatant contradiction inherent in special relativity. I'm being aware that casual statements about complex theories may sometimes lack mathematical rigor in their effort to explain those complex theories to people who may not have the background needed for a fully rigorous explanation.

BUT, each individual photon is at rest, just sitting there, at 0 velocity, traveling at "c", just as I am sitting here in my chair typing this, at 0 velocity in numerous reference frames.Nope. Light travels at the same speed in all reference frames, and that speed is not zero. That's one of the founding postulates of special relativity.

When Einstein did his 'thought experiments', by defining photons as 'having no rest frame', and using SCI-FI spaceships traveling at near "c", and all the way to "c", he started using the 0 velocity 'rest frame' to determine reality. And THEN the 'time dilation', Lorentz contraction, etc, just compensates to make 'that reality' mathematically consistent.Well, it's true that Einstein started from some simple thought experiments about how light behaves (though you won't find him using any examples of an observer moving at the speed of light), mostly to try to figure out a way to get electrodynamics and mechanics to work according to the same set of rules. And of course what's really important is not that the resulting theory is mathematically consistent (which it is), it's that it is also consistent with all the experiments designed to test it since then.

Steve Limpus
2007-Aug-27, 08:45 PM
Tensor's pretty bright. I'd assume that he's aware that it's not really possible to accelerate instantaneously to the speed of light.

I've always been curious: we know photons have the characteristics of waves and of particles, so does a photon accelerate too? I assume not, but why not? Is it because a photon has no mass?

Isn't it the case that nothing with mass can travel at light speed, including any observer we could conceive of? Except in Star Trek of course. Does that make some of these thought experiments moot (regarding time stopping at 'c') or have I missed something important?

I've heard it said that were it not for relativity and the speed limit 'c' the entire history of the universe would play out instantaneously--how does that work?

Hope these aren't dumb questions!

Tensor
2007-Aug-28, 12:27 AM
I agree, that's the way I understand it. Perhaps Richard could comment on this.

Richard is quite aware of this (if I remember our posts to each other correctly).

Thanks for the reference on rotation.

Not a problem. For a better reference, the explanation is on page 92 and a pictoral representation is on page 93. This is in the second edition.

Tensor
2007-Aug-28, 02:47 AM
Tensor's pretty bright.

I'm gonna hold you to that. :)

I'd assume that he's aware that it's not really possible to accelerate instantaneously to the speed of light.

That would be a good assumption.

But his statement gets most of the idea across.

That was the main idea. If you go back to the post that RussT took that statement out of, you will notice that it was an answer to someone who, I thought, would understand a simpler reply much better.

A more precise wording might be that if you travel from here to Alpha

Good explanation snipped.

then it will take you a whole second to travel four billion light years.

Your explanation is certainly more correct.

As always, don't take a casual statement attempting to explain the general idea of a theory to someone as the theory itself. If you want to know how differently moving observers will measure time according to special relativity, you need to look at the math of special relativity. And if you want to address problems that you think exist within special relativity, you definitely need to be looking at the math itself.

This has been, from my point of view, a problem with RussT's ideas. He's very good at taking quotes from different sources to support his ideas, but he seems to be very weak at actually understanding the math behind those quotes. As a result, to those who understand the math, his ideas seem rather quixotic.

Well, I'm not "ignoring" some blatant contradiction inherent in special relativity. I'm being aware that casual statements about complex theories may sometimes lack mathematical rigor in their effort to explain those complex theories to people who may not have the background needed for a fully rigorous explanation.

I have, what I think, is a really good example of this concerning Mercury's anomalous precession. While I realize that it is due to the non-linearity of the GR equations, expressed, in the math, as a second order effect of the power expansion series, I like to explain it as the difference between Newtonian Gravity (where mass creates gravity) and GR (where energy is the cause of gravity). One can point out that the energy of the Sun's gravitational field adds to the gravity caused by the Sun. This extra bit of energy causes the extra tug on Mercury, causing the precession. While this explanation is obviously not complete (for one, it ignores the elliptical component of Mercury's orbit), it illustrates some of the differences of the two theories and the non-linearity of the GR equations, for people who have no idea what a power expansion is.

RussT
2007-Aug-28, 09:34 AM
Tensor's pretty bright. I'd assume that he's aware that it's not really possible to accelerate instantaneously to the speed of light.

See, you are already using semantics here ;)

Photons/Light accelerates instantaneously to "c". (which by the way is impossible for electrons to magically accomplish!)

A more precise wording might be that if you travel from here to Alpha Centauri, moving at arbitrarily close to the speed of light, the trip will take roughly four years for outside observers, but will be arbitrarily short for the person travelling. Depending on how fast you go, the trip could take a year as measured by the traveller, or a day, or a second, or a nanosecond. Essentially no time as measured by an outside observer, if the traveller is moving quickly enough. And it still scales. If you're travelling fast enough that time dilation means you measure a nanosecond to go four light years, then it will take you a whole second to travel four billion light years.

Sure it still scales...it is all robustly consistent mathematically. Infact, it is absolutely 'Crap your Pants' perfect, as Publius has been know to quip.

However, it 'assumes' that the current defining of light/photons as having no 'rest frame' and experiencing no time, is correct, and that it is an invalid reference frame.

Originally Posted by RussT
BUT, each individual photon is at rest, just sitting there, at 0 velocity, traveling at "c", just as I am sitting here in my chair typing this, at 0 velocity in numerous reference frames.

Nope. Light travels at the same speed in all reference frames, and that speed is not zero. That's one of the founding postulates of special relativity.

I 100% agree that light/photons travel at a constant "c", In Vacua/Einstein 'empty universe', in all reference frames. However, you switched to 'light', where I said each individual photon.

Each individual photon (wave) IS just sitting still, at 0 velocity, in/on its Point (Particle), which is carrying it at "c". BUT I don't even need to 'prove' that, to show what is really happening here. Also, even if you assume that the photon is really sitting in/on the 'particle', if you defined the particle the same way as you currently define light in its own frame, then the 'particle' could travelto infinity, instantly in its own frame, and that is still Impossible.

When you get to the very limit of the extremes (ie; Time 'frozen' at the event horizons) is where, when it it is understood correctly (And YES, I do understand!!! Playing the "MATH CARD" will not work anymore, besides, it is Ad Hom to attack, what you or Tensor 'assume' is 'my understanding', with it!!), you can flesh out 'what is really happening'.

SO, when the end result of assigning simultaneity to all photons in their light path, in lights reference frame, and 0 time that a photon experiences, in its own frame, results in photons/light being able to travel to infinity, instantly, in its own frame, YA gotta know that that is Impossible.

And then what happens...you/they just say that it is an INVALID reference frame, BUT YA want to keep all the dilation and contraction...and yes, when you do that, it all scales purr-fectly ;)

SO, what happened, for this to become SOOOO acceptable? That light could travel clear across the universe instantaneously, in its own frame, and Time could 'freeze'? (btw, light/photons do freeze time in a way...when they hit the lens of any of our cameras/telescopes).

That darned 'Spaceship' and those thought experiments, and what would a stationary frame and a moving frame see at relavistic speeds...IT is ALL SCI-FI, and Einsteins SR convinced mainstream (Or I guess it would be more correct to say what is now mainstream), that you/they were seeing what is "REAL" from a 0 velocity position when you hold something stationary in the same reference frame.

SO, sure, if you were sitting on the single photon, traveling at "c", you could not measure your speed, so you have to measure it from another frame to see the reality of it traveling at "c". Just like if you were sitting on the bullet, you could not measure reality from that frame, sitting on the bullet at 0 velocity in your own frame.

We always transfer to another frame to see the reality when we are at 0 velocity in our frame, just as I am sitting here at 0 velocity in my chair, time is ticking away 1 second at a time.

So all the experiments, like Pound/Rebka, that require the 'stationary', are not seeing the reality...you have to switch to the 'other frame' to see the reality...assigning gravitational redshift to the gamma rays in that experiment looks correct, BUT it is the earths rotation that is really causing those rays appear to be sped up closer to a gravitational source. Time automatically goes slower at altitude, and faster toward the center of the earth because of the earths rotation.

And this is what I meant when I finally realized what Ken G was actually saying here...

Originally Posted by RussT
In addition this is NOT a trivial or 'be careful' evaluation of what happens in 'reference frames', and ultimately what it really means.

Quote:
Originally Posted by KenG From post 18...
We must avoid the illusions that come from taking what is happening in our frame, transforming to the photon frame where it all stacks up on top of itself and looks just like a point, and then reason from that point what should happen when we transform back to our reference frame.

Quote:
Originally Post by RussT
You just described what they are doing when Time is 'frozen' at the event horizon of a black hole. Didn't You?

Quote:
Originally Posted by KenG
Yes, very much so. Saying time is "frozen" at an event horizon is also extremely misleading, but in a somewhat different way. It is impossible to enter the frame of the photon to see that "frozen" time, whereas you can be in the frame of something at an event horizon-- and if you do, time isn't frozen at all.

Quote:
Originally Posted by RussT
There are only two options with this 'what is happening at the point of the reference frame where we are trying to determine, based on the MAths, what is happening there.

1. when we get to the refrence frame where we are trying to determine, 'what is happening there', we MUST decide that the 'Opposite' of what the maths is showing us is 'what is happening', just as KenG showed above. That is NOT just a matter of 'being careful'!!!
or 2. The maths need to be refigured in a way that DOES show the reality of what is happening there.

Everyone has always assumed that that scenario was only applicable at the Event Horizon of a black hole, BUT that is NOT true...it applies to all reference frames where we are trying to determine 'what happens there'!!!

Now, here is what I will admit...I am not sure how to solve this. :clap::clap:
ETA; I meant what someone is going to need to do mathematically. I know how to solve the Time dilemma ;)

We know that Light travels at "c" in Vacua, and that all reference frames see it as so, unless it is curved by a massive object, BUT do we just have to accept that we have to 'figure out' what is happening at the Event Horizon, or whatever frame we are looking for 'what is happening there', OR is there a way to switch the maths around so it will show correctly, that Time is just flowing at the event horizon as the free faller see it.

Tensor
2007-Aug-28, 12:35 PM
(And YES, I do understand!!! Playing the "MATH CARD" will not work anymore,...

Hmmmmmm...

OR is there a way to switch the maths around so it will show correctly, that Time is just flowing at the event horizon as the free faller see it.

Does anyone else see the dichotomy in these two statements? I could give you a hint, but then, since you understand the math all so well, I guess we'll just have to wait until you find it.

....besides, it is Ad Hom to attack, what you or Tensor 'assume' is 'my understanding', with it!!),

I'm not assuming anything. You have made statements to the fact that you don't understand the math and have demonstrated, that you don't understand, in the comments above and in other posts. As to whether or not it is an ad hom, your understanding or lack of understanding is directly related to your claims. You don't show, and have claimed you don't know, the math. This makes your claims rather shaky. As some of your comments directly contradict the actual math.

Grey
2007-Aug-28, 01:05 PM
See, you are already using semantics here ;)

Photons/Light accelerates instantaneously to "c". (which by the way is impossible for electrons to magically accomplish!)I would disagree. Photons are created already moving at the speed of light. They don't get created first, and then accelerate. That answers Steve Limpus's question about photon acceleration as well. Photons don't accelerate, they are always moving at light speed from the moment they are created to the moment they are absorbed.

Sure it still scales...it is all robustly consistent mathematically. Infact, it is absolutely 'Crap your Pants' perfect, as Publius has been know to quip.

However, it 'assumes' that the current defining of light/photons as having no 'rest frame' and experiencing no time, is correct, and that it is an invalid reference frame.Well, you're contradicting yourself here, since, as I've pointed out, if it assumes that the hypothetical rest frame of a photon is in fact not a valid reference frame, then we can't properly say anything about what time is doing in such a frame. But it's more important to point out that it doesn't actually matter what it assumes. The important part is that, after making those assumptions, the theory makes quantitative, measurable predictions about the results of various experiments, and that those results match what we see when we actually carry out those experiments.

I 100% agree that light/photons travel at a constant "c", In Vacua/Einstein 'empty universe', in all reference frames. However, you switched to 'light', where I said each individual photon.

Each individual photon (wave) IS just sitting still, at 0 velocity, in/on its Point (Particle), which is carrying it at "c". BUT I don't even need to 'prove' that, to show what is really happening here. Also, even if you assume that the photon is really sitting in/on the 'particle', if you defined the particle the same way as you currently define light in its own frame, then the 'particle' could travelto infinity, instantly in its own frame, and that is still Impossible.

...

SO, when the end result of assigning simultaneity to all photons in their light path, in lights reference frame, and 0 time that a photon experiences, in its own frame, results in photons/light being able to travel to infinity, instantly, in its own frame, YA gotta know that that is Impossible.For special relativity, there is no reference frame in which light can travel an infinite distance instantly. That's true whether we're using "classical" special relativity and treating light as a wave, or quantum electrodynamics (which incorporates special relativity), in which light can be considered to be composed of photons. If you want to create your own theory, where it is possible to have the rest frame of a photon, that might be a problem for your theory, but that doesn't make it so for relativity.

And then what happens...you/they just say that it is an INVALID reference frame, BUT YA want to keep all the dilation and contraction...and yes, when you do that, it all scales purr-fectly ;)It's not that anyone wants to keep time dilation and length contraction. I think most physicists would have been happier if we could just use Newtonian mechanics. However, that doesn't match the results of experiment. We use special relativity because it works, not because we thought Einstein was a great guy.

SO, what happened, for this to become SOOOO acceptable? That light could travel clear across the universe instantaneously, in its own frame, and Time could 'freeze'? (btw, light/photons do freeze time in a way...when they hit the lens of any of our cameras/telescopes).Light doesn't travel instantaneously in any relativistic reference frame, and time doesn't "freeze" for any observer.

That darned 'Spaceship' and those thought experiments, and what would a stationary frame and a moving frame see at relavistic speeds...IT is ALL SCI-FI, and Einsteins SR convinced mainstream (Or I guess it would be more correct to say what is now mainstream), that you/they were seeing what is "REAL" from a 0 velocity position when you hold something stationary in the same reference frame.No, the thought experiments didn't change the mainstream view by themselves. It was the fact that the predictions based on those thought experiments match observation.

SO, sure, if you were sitting on the single photon, traveling at "c", you could not measure your speed, so you have to measure it from another frame to see the reality of it traveling at "c". Just like if you were sitting on the bullet, you could not measure reality from that frame, sitting on the bullet at 0 velocity in your own frame.You can't be sitting on a photon, travelling at the speed of light. However, you can be sitting on a bullet travelling along with it at some speed less than c, and you'll work out all the same laws of physics that you would if you were instead watching the bullet zip past you with some significant velocity. You may not like it, but it works.

Grey
2007-Aug-28, 01:15 PM
I'm gonna hold you to that. :):)

I have, what I think, is a really good example of this concerning Mercury's anomalous precession. While I realize that it is due to the non-linearity of the GR equations, expressed, in the math, as a second order effect of the power expansion series, I like to explain it as the difference between Newtonian Gravity (where mass creates gravity) and GR (where energy is the cause of gravity). One can point out that the energy of the Sun's gravitational field adds to the gravity caused by the Sun. This extra bit of energy causes the extra tug on Mercury, causing the precession. While this explanation is obviously not complete (for one, it ignores the elliptical component of Mercury's orbit), it illustrates some of the differences of the two theories and the non-linearity of the GR equations, for people who have no idea what a power expansion is.I'd agree that this is a good example. It makes sense to try to choose how you phrase something with your audience in mind, to try to get the main idea across without confusing them. Someone who has a few questions about relativity doesn't need the full-blown math of general relativity; that won't help them. Saying that time slows down more and more as you get closer to the speed of light, and that if you were going at the speed of light time wouldn't pass at all, gets across the idea, even if it's not rigorous. And yes, RussT should not then mistake it for a rigorous statement and try to critique it as though it were.

EvilEye
2007-Aug-28, 09:15 PM
As far as the "Star Trek" question...

They would have a real problem going about the star systems and meeting up with old friends who stayed put.

Ship time at even Warp 1 would be instantaneous. But from outside the ship, time would be measured as light-years. So when they arrived, they would be their steady-aged selves from whence they left, and those they arrived upon would have a history book (log-book) explaining who to look for in the future...

Steve Limpus
2007-Aug-28, 10:12 PM
Correct me if I'm wrong, but it seems the properties of photons have an awful lot to do with their mass-less nature (the ability to travel at 'c' and to accelerate instantaneoulsy etc) and as we think particles derive mass from the Higgs Field via the Higgs Boson, can anyone explain in layman's terms if/how the upcoming experiments at CERN are expected to inform our understanding of Relativity?

EvilEye
2007-Aug-28, 11:29 PM
Correct me if I'm wrong, but it seems the properties of photons have an awful lot to do with their mass-less nature (the ability to travel at 'c' and to accelerate instantaneoulsy etc) and as we think particles derive mass from the Higgs Field via the Higgs Boson, can anyone explain in layman's terms if/how the upcoming experiments at CERN are expected to inform our understanding of Relativity?

Maybe.. but they will never see a photon INSTANTLY appear where they expect it from where it left.

The photon is the one that experiences the "no time". Not the observer.

RussT
2007-Aug-29, 07:42 AM
Originally Posted by RussT
OR is there a way to switch the maths around so it will show correctly, that Time is just flowing at the event horizon as the free faller see it.

Does anyone else see the dichotomy in these two statements? I could give you a hint, but then, since you understand the math all so well, I guess we'll just have to wait until you find it.

Uh, you left out the full context of the quote!

We know that Light travels at "c" in Vacua, and that all reference frames see it as so, unless it is curved by a massive object, BUT do we just have to accept that we have to 'figure out' what is happening at the Event Horizon, or whatever frame we are looking for 'what is happening there', OR is there a way to switch the maths around so it will show correctly, that Time is just flowing at the event horizon as the free faller see it.

Yea, so I should have added to the last part of what you quoted...From our frame of reference.

In other words, light/photons experience Time just like everything else in our universe. In fact we know that they experience 1 second for every 186, 000 miles they travel. Just because they are curved so strongly at the event horizon that they can no longer escape, does Not mean that time stops for them, even from our distant frame.

BUT, the way the maths are configured now, Time is frozen at the event horizon, from a distance, and so just like I showed with KenG's example, and Cougars example in the 'hole in the universe' thread, and Publius' example of what the 'free faller' sees inside the event horizon, where for him space and time are not 'flipped'...we are always having to see 'reality' from their frame, The opposite, from our frame, of what the maths are showing is 'real'.

SO, why does everyone keep switching to the 'other frame' to say what is 'really happening there', BUT then when it comes to the 'reality' of what the maths are showing, they insist it must be right from our 'stationary' frame?

BUT, mainstream still wants to say that Time and Space are 'flipped' inside the event horizon, and that at the singularity, there is a 'repeling' - sign, that means that nothing can go straight through.

AND, that is built right into the SR/GR equations, based on Einsteins concepts (Unless of course it has been switched from Einsteins orginal equations, to 'fit' the FLRW EFE) of what 'space' is made up of.

http://en.wikipedia.org/wiki/Metric_..._relativity%29

Originally Posted by Wiki
In general relativity, the terms metric and line element are often used interchangeably.

The line element ds2 imparts information about the causal structure of the spacetime. When ds2 < 0, the interval is timelike and the square root of the absolute value of ds2 is an incremental proper time. Only timelike intervals can be physically traversed by a massive object. When ds2 = 0, the interval is lightlike,and can only be traversed by light. When ds2 > 0, the interval is spacelike and the square root of ds2 acts as an incremental proper length. Spacelike intervals cannot be traversed, since they connect events that are out of each other's light cones. Events can be causally related only if they are within each other's light cones.

Quote:
Originally Posted by Wiki
One of the core ideas of general relativity is that the metric (and the associated geometry of spacetime) is determined by the matter and energy content of spacetime. Einstein's famous field equations:

The Bold in the first paragraph, should only apply once past/through the Ring Singularity, where the worm hole (Which is made up of "Exotic Matter" only) traverses to the white hole, that is 'leaking Gravity/Exotic Matter' to OUR universe at "c".

That is where the light cones are seperated, and can have no causal effect, BUT the Exotic Matter can come our way, BUT nothing can go back that way, against 'space/time' coming to us. Don't thinking "Flipping" at the Ring Singularity...just space/time flowing to us at "c".

As I have said many time now, Einstein did NOT have enough information to make the decisions he made about what 'space/time' is made up of...he did NOT know of 'Exotic Matter', SMBH's or Voids.

I Shouln't have even used the term 'free faller', as SCI-FI'ing this whole thing is what has so convoluted everything in the first place.

NO human or human built contraption could survive anywhere near a stellar black hole let alone a SMBH!

As for the Maths...I have never said that I can do them, or even that I understand ALL of the maths being used, BUT I am saying that I DO understand what mainstream is saying about how the maths are being applied to the different regimes, and especially where those are at their most extreme.

Let me ask you this...Do you still think that SMBH's are made the same as stellar black holes, but just more massive?

RussT
2007-Aug-29, 08:21 AM
I would disagree. Photons are created already moving at the speed of light. They don't get created first, and then accelerate. That answers Steve Limpus's question about photon acceleration as well. Photons don't accelerate, they are always moving at light speed from the moment they are created to the moment they are absorbed.

Ah, you are probably refering to the current paradigm of how photons are created inside of stars, where they take millions of years to make their way to the surface to be released.

So please explain when you turn on your light in a dark room, how those trapped electrons are 'instantaneously' 'accelerating' those massless photons to 186,000mps in all/every directions?

Well, you're contradicting yourself here, since, as I've pointed out, if it assumes that the hypothetical rest frame of a photon is in fact not a valid reference frame, then we can't properly say anything about what time is doing in such a frame.

I don't think I am the one doing the contradicting here. Let's look at what is actually being said here...

You have said more than once...that light in its own frame is NOT a valid frame of reference, and now are saying...[then we can't properly say anything about what time is doing in such a frame.]

AND, the same thing applies to defining light in its own frame as having zero velcocity in its reference frame because from that frame the photon is simultaneously along all points on it's path from source to sink. OR actually from source to Infinity.

Now, the result of that, is that, in its own frame, no matter how far the trip for the individual photons is, it is Instantaneous, even 100 billion light yrs away...that's impossible, BUT...now you/they/your Profs all throughout your physics education, Insist, that because all the Maths work so well, in all other frames, that it is okay just to deem this, light in its own frame, that we can't really say anything about, because it is NOT a proper frame, Invalid. Just ignore it, and declare it meaningless.

If it is an Invalid, meaningless frame, then we should NOT define anything in it at all, Period.

We know that Light/Photons travel at "c" in Vacua at 186,000mps. And that there is the Shapiro Effect when massive objects are involved.

Grey
2007-Aug-29, 02:10 PM
Ah, you are probably refering to the current paradigm of how photons are created inside of stars, where they take millions of years to make their way to the surface to be released.Um, no. I'm talking about any photons created anywhere by any process.

So please explain when you turn on your light in a dark room, how those trapped electrons are 'instantaneously' 'accelerating' those massless photons to 186,000mps in all/every directions?I already said that photons aren't accelerated. When they are created, they're moving at light speed. That's the only way a photon can move. Creating a photon and accelerating to light speed are not two separate steps.

I don't think I am the one doing the contradicting here. Let's look at what is actually being said here...

You have said more than once...that light in its own frame is NOT a valid frame of reference, and now are saying...[then we can't properly say anything about what time is doing in such a frame.]That's true. And it doesn't especially hurt that we can't say anything about the rate of time in such a hypothetical reference frame, because there's no way we can move any kind of clock at light speed to see how it behaves. There are clocks that we can get to mvoe very fast relative to us: unstable particles with some well-defined half life. But all such particles have mass, and never move at light speed.

AND, the same thing applies to defining light in its own frame as having zero velcocity in its reference frame because from that frame the photon is simultaneously along all points on it's path from source to sink. OR actually from source to Infinity.Not really. Even if we take the really loose interpretation of the math and apply special relativistic equations where they don't really belong (and ignore or avoid the division by zero that we'll run across), the points from source to sink end up being the same. That is, just as we'd observe time to pass arbitrarily slowly for an observer moving arbitrarily close to light speed, an observer so moving would see the universe length contracted by an arbitrary amount, so that the distance from source to sink becomes arbitrarily short. Or, in the casual phrasing someone might use, it's okay that no time passes for a photon, because it doesn't travel any distance. :)

Now, the result of that, is that, in its own frame, no matter how far the trip for the individual photons is, it is Instantaneous, even 100 billion light yrs away...that's impossible, BUT...now you/they/your Profs all throughout your physics education, Insist, that because all the Maths work so well, in all other frames, that it is okay just to deem this, light in its own frame, that we can't really say anything about, because it is NOT a proper frame, Invalid. Just ignore it, and declare it meaningless.

If it is an Invalid, meaningless frame, then we should NOT define anything in it at all, Period.We don't. We don't "define" anything in any reference frame. All the properties that we ascribe to photons are as determined from the reference frame of an observer watching the photon go by, not from the perspective of the photon itself.

Special relativity tells us that if different observers are moving differently, they will measure different times and distances between the same events. The math tells us how to take the measurements one observer might get, together with information about how a second observer is moving relative to the first, and figure out what that second observer would measure. It works really well. It does not, however, actually allow us to figure out what an observer moving past us at light speed might see. That's not a big problem, though, because we also know that it's not actually possible for such an observer to exist.

We know that Light/Photons travel at "c" in Vacua at 186,000mps. And that there is the Shapiro Effect when massive objects are involved.That's true. The Shapiro effect is a general relativistic effect, which I assumed we weren't getting into, given the title of this thread.

Steve Limpus
2007-Aug-30, 01:02 AM
I just came across this piece, on the SLAC (Stanford Linear Accelerator Center) website; it talks about real world relativistic effects inside their accelerator:

http://www2.slac.stanford.edu/vvc/theory/relativity.html

Peculiar Relativistic Effects
Length Contraction and Time Dilation

One of the strangest parts of special relativity is the conclusion that two observers who are moving relative to one another, will get different measurements of the length of a particular object or the time that passes between two events.

Consider two observers, each in a space-ship laboratory containing clocks and meter sticks. The space ships are moving relative to each other at a speed close to the speed of light. Using Einstein's theory:

Each observer will see the meter stick of the other as shorter than their own, by the same factor gamma. This is called length contraction.
Each observer will see the clocks in the other laboratory as ticking more slowly than the clocks in his/her own, by a factor gamma. This is called time dilation.
In particle accelerators, particles are moving very close to the speed of light where the length and time effects are large. This has allowed us to clearly verify that length contraction and time dilation do occur.

Time Dilation for Particles

Particle processes have an intrinsic clock that determines the half-life of a decay process. However, the rate at which the clock ticks in a moving frame, as observed by a static observer, is slower than the rate of a static clock. Therefore, the half-life of a moving particles appears, to the static observer, to be increased by the factor gamma.

For example, let's look at a particle sometimes created at SLAC known as a tau. In the frame of reference where the tau particle is at rest, its lifetime is known to be approximately 3.05 x 10-13 s. To calculate how far it travels before decaying, we could try to use the familiar equation distance equals speed times time. It travels so close to the speed of light that we can use c = 3x108 m/sec for the speed of the particle. (As we will see below, the speed of light in a vacuum is the highest speed attainable.) If you do the calculation you find the distance traveled should be 9.15 x 10-5 meters.

d = v t

d = (3 x 108 m/sec)( 3.05 x 10-13 s) = 9.15 x 10-5 m

Here comes the weird part - we measure the tau particle to travel further than this!

Pause to think about that for a moment. This result is totally contradictory to everyday experience. If you are not puzzled by it, either you already know all about relativity or you have not been reading carefully.

What is the resolution of this apparent paradox? The answer lies in time dilation. In our laboratory, the tau particle is moving. The decay time of the tau can be seen as a moving clock. According to relativity, moving clocks tick more slowly than static clocks.

We use this fact to multiply the time of travel in the taus moving frame by gamma, this gives the time that we will measure. Then this time times c, the approximate speed of the tau, will give us the distance we expect a high energy tau to travel.

What is gamma in this case? It depends on the tau's energy. A typical SLAC tau particle has a gamma = 20. Therefore, we detect the tau to decay in an average distance of 20 x (9.15 x 10-5 m) = 1.8 x 10-3 m or approximately 1.8 millimeters. This is 20 times further than we expect it to go if we use classical rather than relativistic physics. (Of course, we actually observe a spread of decay times according to the exponential decay law and a corresponding spread of distances. In fact, we use the measured distribution of distances to find the tau half-life.)

Observations particles with a variety of velocities have shown that time dilation is a real effect. In fact the only reason cosmic ray muons ever reach the surface of the earth before decaying is the time dilation effect.

Length Contraction

Instead of analyzing the motion of the tau from our frame of reference, we could ask what the tau would see in its reference frame. Its half-life in its reference frame is 3.05 x 10-13 s. This does not change. The tau goes nowhere in this frame.

How far would an observer, sitting in the tau rest frame, see an observer in our laboratory frame move while the tau lives?

We just calculated that the tau would travel 1.8 mm in our frame of reference. Surely we would expect the observer in the tau frame to see us move the same distance relative to the tau particle. Not so says the tau-frame observer -- you only moved 1.8 mm/gamma = 0.09 mm relative to me. This is length contraction.

How long did the tau particle live according to the observer in the tau frame? We can rearrange d = v x t to read t = d/v. Here we use the same speed, Because the speed of the observer in the lab relative to the tau is just equal to (but in the opposite direction) of the speed of the tau relative to the observer in the lab, so we can use the same speed. So time = 0.09 x 10-3 m/(3 x 108)m/sec = 3.0 x 10-13 sec. This is the half-life of the tau as seen in its rest frame, just as it should be!

Hope someone finds it useful. :shifty:

StateBoiler
2007-Aug-30, 04:22 AM
Is modern cosmology science or folklore?

From American Scientist. Casts doubts into relativity theory in general.

http://www.americanscientist.org/template/AssetDetail/assetid/55839?&print=yes

RussT
2007-Aug-30, 10:44 AM
That's true. And it doesn't especially hurt that we can't say anything about the rate of time in such a hypothetical reference frame,

Well then, since it is such a hypothetical reference frame, there is absolutely no way that it makes any sense what-so-ever, to make the 'assumption' that light is simultaneous at all points along it path to Infinity, or source to sink.

When they are created, they're moving at light speed.

How does the electron accomplish that? When I flip the switch to turn on my light, the electrons emit photons, right at the source of the bulb.

Not really. Even if we take the really loose interpretation of the math and apply special relativistic equations where they don't really belong (and ignore or avoid the division by zero that we'll run across), the points from source to sink end up being the same.

Grey, If I were using the same arguement here that you are, on anything I was trying to show, here is what you would say to me...

[Even if we take the really loose interpretation of the math and apply special relativistic equations where they don't really belong (and ignore or avoid the division by zero that we'll run across), the points from source to sink end up being the same.]

You cannot use the theory as a proven, to try and make a point as to its initial postulate.

And yes, that division by 0 is telling , isn't it. Besides, by defining light as simultaneous at every point along its path source to sink, or to Infinity, in effect, makes light motionless, since in its own frame, it is instantaneous at any distance for points A and B, and you just said...[I already said that photons aren't accelerated. When they are created, they're moving at light speed. That's the only way a photon can move. Creating a photon and accelerating to light speed are not two separate steps.]

That is, just as we'd observe time to pass arbitrarily slowly for an observer moving arbitrarily close to light speed, an observer so moving would see the universe length contracted by an arbitrary amount, so that the distance from source to sink becomes arbitrarily short. Or, in the casual phrasing someone might use, it's okay that no time passes for a photon, because it doesn't travel any distance.

Which makes this circular reasoning. :)

As I have said, there are really only two choices.

Either redo the Maths to eliminate that 0, OR, what all of this really means is that we have to see the Reality...'what's really happening', from the perspective of the 'other frame'.

BUT, that's not the only thing that is happening here. This 'stationary frame' business, coupled with the SCI-FI spaceship traveling relavistically, or the 'stationary train station' seeing massive/macro objects moving relavistically, and THEN try to say we are seeing 'reality' when that moving relavistically onject is in "Its Rest Frame'...does NOT work...you cannot have two things at rest and "SEE REALITY" :)

Defining Light as simultaneous at all points along its path...setting the speed of light to 0 in its own frame, and then defining it as experiencing 0 time in its own frame, is setting the whole universe to 0, and then redefining it, based on a totally wrong assumptions, because they were so convinced that time dilation and Lorentz contraction was "REAL"...

We absolutely know that light cannot be instantaneous across any distance, IN ANY FRAME!

Grey
2007-Aug-30, 05:22 PM
Well then, since it is such a hypothetical reference frame, there is absolutely no way that it makes any sense what-so-ever, to make the 'assumption' that light is simultaneous at all points along it path to Infinity, or source to sink.Yes, I'd actually agree with that.

How does the electron accomplish that? When I flip the switch to turn on my light, the electrons emit photons, right at the source of the bulb.To be honest, I don't think anyone knows the answer to that question. Charged objects can interact through the electromagnetic force, producing or absorbing photons in the process. But I don't think we know why charged objects can do that. I'm not even certain if there's a way to ever know that. We know some of the mechanisms involved, and can give a lot of the details of what happens, but that's it.

Grey, If I were using the same arguement here that you are, on anything I was trying to show, here is what you would say to me...

[Even if we take the really loose interpretation of the math and apply special relativistic equations where they don't really belong (and ignore or avoid the division by zero that we'll run across), the points from source to sink end up being the same.]

You cannot use the theory as a proven, to try and make a point as to its initial postulate.I'm not making a point about the original postulate, merely extrapolating the results of the theory. If (ignoring the advice of rigorous mathematicians :)) you decide to take the limit of the relativistic equations of motion as the object in question approaches the speed of light, and take that limit as a real representation of what happens at the speed of light, you'll find that an observer moving along with the light would record no time passing between emission and absorption. However, you would also find that such a hypothetical observer would measure the distance between the point of emission and absorption as zero. So, the proper time measured in travelling nowhere is zero. Which makes a certain amount of sense.

And yes, that division by 0 is telling , isn't it. Besides, by defining light as simultaneous at every point along its path source to sink, or to Infinity, in effect, makes light motionless, since in its own frame, it is instantaneous at any distance for points A and B, and you just said...[I already said that photons aren't accelerated. When they are created, they're moving at light speed. That's the only way a photon can move. Creating a photon and accelerating to light speed are not two separate steps.]Yes, the division by zero tells us that if we want to heed the advice of the rigorous mathematicians, we really shouldn't be trying to do coordinate transforms into the rest frame of a photon in the first place. If we don't try to do that, then we aren't defining light as simultaneously at every point along its path. In any reference frame an observer can be in, light is moving at c along its path.

As I have said, there are really only two choices.

Either redo the Maths to eliminate that 0, OR, what all of this really means is that we have to see the Reality...'what's really happening', from the perspective of the 'other frame'.Neither of those choices is a good one. If we change the math to eliminate the zero, we'll end up with equations that don't accurately predict what we'll measure at speeds less than c, which is eminently testable. And trying to understand what reality is like from the perspective of an observer that cannot possibly exist isn't going to work, since there's no way we can ever test any of our ideas, even in principle. Of course, there's a third possibility. We can stop trying to bring up philosophic objections to special relativity because it doesn't allow us to predict how the universe behaves from the perspective of an observer that cannot exist accordin gto the theory, and instead accept that it makes sense to only try to describe the universe from the perspetive of observers that can exist.

BUT, that's not the only thing that is happening here. This 'stationary frame' business, coupled with the SCI-FI spaceship traveling relavistically, or the 'stationary train station' seeing massive/macro objects moving relavistically, and THEN try to say we are seeing 'reality' when that moving relavistically onject is in "Its Rest Frame'...does NOT work...you cannot have two things at rest and "SEE REALITY" :)Except that it does work. Every test that we've done of relativity works out.

Defining Light as simultaneous at all points along its path...setting the speed of light to 0 in its own frame, and then defining it as experiencing 0 time in its own frame, is setting the whole universe to 0, and then redefining it, based on a totally wrong assumptions, because they were so convinced that time dilation and Lorentz contraction was "REAL"...Whether this is true or not is irrelevant, because as I've pointed out several times, we do not define light as being at rest in its own frame, because we do not even define such a frame in the first place. In special relativity, light moves at a speed of c in every possible reference frame. That's one of the founding postulates.

We absolutely know that light cannot be instantaneous across any distance, IN ANY FRAME!And it's not. In any valid reference frame, light moves at a finite speed. And even if you want to allow bending the rules and permit invalid reference frames, light never travels any nonzero distance instantaneously.

Steve Limpus
2007-Aug-30, 08:36 PM
Is modern cosmology science or folklore?

From American Scientist. Casts doubts into relativity theory in general.

http://www.americanscientist.org/template/AssetDetail/assetid/55839?&print=yes

Interesting article. I think it is challenging the concepts of inflation, dark matter and dark energy; more so than relativity.

I'm a little dubious though. I'm sure cosmologists would agree there is a lot of work to be done; and I just don't think it's all that clever to have a crack at the 'problems' of the current theory (which everyone acknowledges) when one doesn't have a better theory. What is the writers' point? Would he rather just disregard all the work of the last century, during which the big bang model smacked down all the competing theories? Methinks the writer may well be proposing to throw out the baby with the bath water.

Enjoyed reading it nonetheless, a degree of skepticism can only be healthy.

Just my \$0.02.

RussT
2007-Aug-31, 07:15 AM
Quote:
Originally Posted by StateBoiler
Is modern cosmology science or folklore?

From American Scientist. Casts doubts into relativity theory in general.

http://www.americanscientist.org/tem...839?&print=yes

Interesting article. I think it is challenging the concepts of inflation, dark matter and dark energy; more so than relativity.

Special Relativity is intimately tied into all cosmology, and is infact more tied into the expansion/redshift definitions, more so than GR.

BUT this was Stateboilers 1st post on BAUT, so I am sure he doesn't realize that there are probably other threads already covering what he linked to.

RussT
2007-Aug-31, 08:18 AM
QUOTE]
Originally Posted by RussT
Well then, since it is such a hypothetical reference frame, there is absolutely no way that it makes any sense what-so-ever, to make the 'assumption' that light is simultaneous at all points along it path to Infinity, or source to sink.[/QUOTE]

Yes, I'd actually agree with that.

Thank you. Some kind of common sense has to prevail here. I Know we need to be extremely careful with that term...common sense, BUT there are some things that just have to be impossible, and again, using the term impossible with extreme caution.

Originally Posted by RussT
How does the electron accomplish that? When I flip the switch to turn on my light, the electrons emit photons, right at the source of the bulb.

To be honest, I don't think anyone knows the answer to that question.

Finally :)

But I don't think we know why charged objects can do that. We know some of the mechanisms involved, and can give a lot of the details of what happens, but that's it.

Yes, as far as I know also, there is no known mechanism that can account for the emission of photons at the source, in this case the light bulb, where the emission by the electrons result in an instantaneous speed for those photons of 186,000mps.

I'm not even certain if there's a way to ever know that.

And you have been doing so well to argue against this 'unscientific' view in the "Spookie Matter at a Distance" thread ;) Don't go KenG on me now :)

In fact, it is actually the two definitions we are talking about (Light simultaneous at all points in its path and 0 time for photons) that is preventing 'finding the "mechanism" for definitively explaning this.

I'm not making a point about the original postulate, merely extrapolating the results of the theory.

And, you know you can't do that ;) This is first principles we are talking about here.

If (ignoring the advice of rigorous mathematicians ) you decide to take the limit of the relativistic equations of motion as the object in question approaches the speed of light, and take that limit as a real representation of what happens at the speed of light, you'll find that an observer moving along with the light would record no time passing between emission and absorption.

Yes, I have already agreed that it is 'crap your pants' Purr-fect mathematically ;)

BUT, that would only be true IF you include the definition of light being simultaneous at all points along its path. Again we "KNOW" it is not, which you agreed to in the first part of this post.

However, you would also find that such a hypothetical observer would measure the distance between the point of emission and absorption as zero. So, the proper time measured in travelling nowhere is zero. Which makes a certain amount of sense.[/QUOTE]

Now, you can use the arguement you gave me above, about 'sense'...it only makes a certain amount of sense, in this case, because you already defined that light was simultaneous at all points along its path to infinity or source to sink.

[QUOTE=Grey]
Yes, the division by zero tells us that if we want to heed the advice of the rigorous mathematicians, we really shouldn't be trying to do coordinate transforms into the rest frame of a photon in the first place.

Nope. Again, it is not about the Maths...they are perfect. It IS about the interpretation. And as I said, when it come to the very extremes, that's where you can really determine if you are on the right track, with the proper understanding.

They/Einstein/Lorentz/whomever did NOT make the assumptions of 'light is simultaneous at all point along it path', and 'light experiences no time in its own frame' as priori and then see what that would mean in other frames!!!

In other words, Einstein came up with light as a Constant "c" in Vacua, and THEN did the thought experiments, with a Macro Object, a spaceship...and what would be 'seen' in "REST FRAMES" at relavistic speeds.

This has more than 1 major problem....first, show me a spaceship that can go .6/.8/.99% of "c"...please, I would like to see the 'experiments' you guys are always talking about ;), BUT secondly, and more importantly, when they did all of the time dilation, simultaneity, Lorentz contracting, even though it all worked mathematically, when they had ro go back to 'light in its own frame' and make those 'hindsight' definitions of light being simultaneous at all points along it path, and photons experience NO TIme, That is what tell you it MUST be wrong, because both of those are Impossible!!! Even in light own Frame!!!

And then, when you come to the things I have shown, about numerous learned people saying that things are actually opposite of what the 'rest frame' from our frame is showing, it becomes clear.

Originally Posted by RussT
In addition this is NOT a trivial or 'be careful' evaluation of what happens in 'reference frames', and ultimately what it really means.

Quote:
Originally Posted by KenG From post 18...
We must avoid the illusions that come from taking what is happening in our frame, transforming to the photon frame where it all stacks up on top of itself and looks just like a point, and then reason from that point what should happen when we transform back to our reference frame.

Quote:
Originally Post by RussT
You just described what they are doing when Time is 'frozen' at the event horizon of a black hole. Didn't You?

Quote:
Originally Posted by KenG
Yes, very much so. Saying time is "frozen" at an event horizon is also extremely misleading, but in a somewhat different way. It is impossible to enter the frame of the photon to see that "frozen" time, whereas you can be in the frame of something at an event horizon-- and if you do, time isn't frozen at all.

Quote:
Originally Posted by RussT
There are only two options with this 'what is happening at the point of the reference frame where we are trying to determine, based on the MAths, what is happening there.

1. when we get to the refrence frame where we are trying to determine, 'what is happening there', we MUST decide that the 'Opposite' of what the maths is showing us is 'what is happening', just as KenG showed above. That is NOT just a matter of 'being careful'!!!
or 2. The maths need to be refigured in a way that DOES show the reality of what is happening there.

Everyone has always assumed that that scenario was only applicable at the Event Horizon of a black hole, BUT that is NOT true...it applies to all reference frames where we are trying to determine 'what happens there'!!!

Neither of those choices is a good one. If we change the math to eliminate the zero, we'll end up with equations that don't accurately predict what we'll measure at speeds less than c, which is eminently testable. And trying to understand what reality is like from the perspective of an observer that cannot possibly exist isn't going to work, since there's no way we can ever test any of our ideas, even in principle. Of course, there's a third possibility. We can stop trying to bring up philosophic objections to special relativity because it doesn't allow us to predict how the universe behaves from the perspective of an observer that cannot exist accordin gto the theory, and instead accept that it makes sense to only try to describe the universe from the perspetive of observers that can exist.

Yes, this is what Publius asked grav to do also, and what every Physics teacher has done since ???

However, this just assumes it must be right, and because the Maths work flawlessly, let's just ignore two things that are Absolutely Impossible...

There is most definitely another possibility...Understand that those two things are Impossible, and that setting everything for light and time to 0 in its own frame, is a manipulation that allows for the redefining of light and time to SUIT the way you 'think' it is working, and just forget the SCI-FI spaceship and what humans can 'see' measure IF they were able to get to relavistic speeds, and just start from the premise trhat Light is traveling at "c" in Vacua, and that all reference frames that we are measuring actual celestial phenomena in have light moveing at "c", unless it is curved by massive bodies...ponderable matter ;). Forget the spaceships hovering at Event Horizons, ropes between relavistic spaceships, time dilated trips to far away places, ETC ETC ETC.

IF, this MUST be done on some level, then understand that those two things are Impossible and realize that Space and Time are "Dimensionless"...they are BOTH constants...
http://en.wikipedia.org/wiki/Fundamental_physical_constant

In physics, dimensionless or fundamental physical constants are, in the strictest sense, universal physical constants that are independent of systems of units and hence are dimensionless quantities.

BUT, alas, the problems are even much deeper that this, and it is so integrated into everything cosmological, and all the way down to QM, that I don't know how it is ever going to be rectified, other than starting all over from scratch. There are many things that are the opposite of what is currently thought, not just the 'other reference frame' is where to see 'what is really happening'.

There is "Definitely" a Medium that is traveling at "c" that is carrying the photons. That IS the 'Mechanism' for how electrons can emit light/photons that instantly are traveling at "c"...regardless if you believe me about where they are coming from.

The MMX DID NOT disprove a medium that is traveling at "c" in ALL/EVERY direction, that can go 'right through' ALL baryonic Matter!!!

BUT, here is the biggest current problem that mainstream has, that this 'Medium' and where it is coming from, and what it is doing will solve.

And Sorry, but another reason I know SR needs to be changed.

Currently, ALL light/photons are 'wave' 'particle' and since E=MC^2, that means that the Higgs (Or whatever turns out to be the 'real' gravity 'particle') mass is embedded IN the photons. In the Primordial universe, the electrons/protons/Neutrons are "Already" in existence, and their collisions are what is causing the High Energy Gamma Radiation, until it all cools enough so that the hydrogen I can form.

SO, since ALL frequencies and energy levels of photons have gravity in them...relavistic mass, how are you/they ever going to seperate the gravity particle from the photons??? That is the ONLY way to Unify GR and QFT :)

Tensor
2007-Sep-01, 04:30 AM
BUT, the way the maths are configured now, Time is frozen at the event horizon, from a distance, and so just like I showed with KenG's example, and Cougars example in the 'hole in the universe' thread, and Publius' example of what the 'free faller' sees inside the event horizon, where for him space and time are not 'flipped'...we are always having to see 'reality' from their frame, The opposite, from our frame, of what the maths are showing is 'real'.

You obviously missed this in my last post:

OR is there a way to switch the maths around so it will show correctly, that Time is just flowing at the event horizon as the free faller see it.

I could give you a hint, but then, since you understand the math all so well, I guess we'll just have to wait until you find it.

SO, why does everyone keep switching to the 'other frame' to say what is 'really happening there', BUT then when it comes to the 'reality' of what the maths are showing, they insist it must be right from our 'stationary' frame?

Because what is real is different for the two observers.

BUT, mainstream still wants to say that Time and Space are 'flipped' inside the event horizon, and that at the singularity, there is a 'repeling' - sign, that means that nothing can go straight through.

I suggest you do some research. I'll even give you a hint. The singularity at the event horizon only shows up in Schwartzchild coordinates and remember GR can use any coordinates.

AND, that is built right into the SR/GR equations, based on Einsteins concepts (Unless of course it has been switched from Einsteins orginal equations, to 'fit' the FLRW EFE) of what 'space' is made up of.

The actual theory and math says nothing about what space-time is made of. Only that it can be warped.

The Bold in the first paragraph, should only apply once past/through the Ring Singularity, where the worm hole (Which is made up of "Exotic Matter" only) traverses to the white hole, that is 'leaking Gravity/Exotic Matter' to OUR universe at "c".

Here's the bold:

When ds2 = 0, the interval is lightlike,and can only be traversed by light.

What is your understanding of a lightlike interval?

That is where the light cones are seperated, and can have no causal effect, BUT the Exotic Matter can come our way, BUT nothing can go back that way, against 'space/time' coming to us. Don't thinking "Flipping" at the Ring Singularity...just space/time flowing to us at "c".

And beyond your say so, what proof do you have? The math says something different and I'll have to go with the math until you can provide something more than your say so.

As I have said many time now, Einstein did NOT have enough information to make the decisions he made about what 'space/time' is made up of...he did NOT know of 'Exotic Matter', SMBH's or Voids.

What is your definition of exotic matter?

I Shouln't have even used the term 'free faller', as SCI-FI'ing this whole thing is what has so convoluted everything in the first place.

Nothing is Sci-fi in either Grey's or my explanations and free faller is a particular apt term, since that desginates an observer who is follwoing an inertial path through spacetime. What is so convoluted is your understanding.

NO human or human built contraption could survive anywhere near a stellar black hole let alone a SMBH!

Again, you need to do some research as it is more difficult to survive near the event horizon of a stellar mass black hole. Again, you might want to do some research.

As for the Maths...I have never said that I can do them, or even that I understand ALL of the maths being used, BUT I am saying that I DO understand what mainstream is saying about how the maths are being applied to the different regimes, and especially where those are at their most extreme.

No, what you understand are the simplified explanations the mainstream gives out to those who don't understand the actual math of the theory. If you actually understood the math, you wouldn't be making some of the claims you make.

Let me ask you this...Do you still think that SMBH's are made the same as stellar black holes, but just more massive?

There are thought to be three or four (or more) different ways to create a supermassive black hole. One is simply a stellar mass black hole that continues to accrete matter. So, in that case, the answer is yes.

RussT
2007-Sep-01, 09:58 AM
You obviously missed this in my last post:

Sorry. I gave a long response in post #79 to your last post and thought my explanation covered everything.

Because what is real is different for the two observers.

I understand that. What is the one major objection that keeps surfacing over and over about black holes, and is the major reason that ECO/MECO/GravaStars even became part of the what ifs...besides the singularity at r=0....That since time is frozen at the event horizon, the black hole can never even form from our perspective/reference frame...Right?

I am saying that Our perspective/reference frame should see time flowing right into the event horizon.

And if the Maths were built on the correct perspective, that nasty little - sign would disappear. That would be the - sign at the singularity inside the event horizon where the 'repeling' happens, so nothing can go straight through a Ring Singularity, so the worm hole is actually a 'side door', that then leads to a white hole. That side door worm hole>white hole is actually what leads to the confusion about white holes being able to possibly spew baryonic matter.

Now, orginally I just thought that the Big Bang 'starting time' with an Schwarzschild inside solution of an expanding Naked Singularity was the culprit for the 'flipping of time and space' inside a SMBH, BUT Tim actually taught me something there, by insisting that I needed a "Metric", and when I researched that I found the real reason he was objecting...

Originally Posted by Wiki
In general relativity, the terms metric and line element are often used interchangeably.

The line element ds2 imparts information about the causal structure of the spacetime. When ds2 < 0, the interval is timelike and the square root of the absolute value of ds2 is an incremental proper time. Only timelike intervals can be physically traversed by a massive object. When ds2 = 0, the interval is lightlike,and can only be traversed by light. When ds2 > 0, the interval is spacelike and the square root of ds2 acts as an incremental proper length. Spacelike intervals cannot be traversed, since they connect events that are out of each other's light cones. Events can be causally related only if they are within each other's light cones.

Quote:
Originally Posted by Wiki
One of the core ideas of general relativity is that the metric (and the associated geometry of spacetime) is determined by the matter and energy content of spacetime. Einstein's famous field equations:

Einstein was making decisions about Space and Time without understanding either.

Originally Posted by RussT
BUT, mainstream still wants to say that Time and Space are 'flipped' inside the event horizon, and that at the singularity, there is a 'repeling' - sign, that means that nothing can go straight through.

I suggest you do some research. I'll even give you a hint. The singularity at the event horizon only shows up in Schwartzchild coordinates and remember GR can use any coordinates.

We may be talking past each other here...I am not talking about a singularity at the event horizon...infact, I realize that it is redshift to infinty that is the Time Frozen at the event horizon, and I am still saying that Time should be flowing right through the event horizon.

BUT, incase you are still objecting to what I am saying mainstream says about the 'flipping' of space and time inside the event horizon, and the repeling at the singularity...

I do get that it is what you say, but I am not at all convinced that it is a reasonable claim. Look at the Schwarzschild metric for a non-rotating black hole. If the radial coordinate r becomes less than the Schwarzschild radius rs, then the term (1-r/rs) becomes negative, and the formerly space-like coordinate (plus sign) becomes a time-like coordinate (negative sign) and vice-versa. So we don't just "flip" space and time for the heck of it, or because we are too narrow minded, or whatever. We "flip" space and time because it is a necessary consequence of the metric. So long as we use any of the standard black hole metrics (Schwarzschild, Kerr, Kerr-Newman, Reisner-Nordstrom and whatever else there may be), then a necessary and unavoidable consequence is that space & time "flip", whether you, we, or anyone else likes it or not.

And, I am saying that Einsteins defining of light as simultaneous at all points along its path to infinity, and photons experiencing NO TIME in its own frame, and THEN determining that light in its own frame is NOT a valid inertial frame, is the mathematical culprit of all of this...

If we look at this...
http://en.wikipedia.org/wiki/Inertial_frame_of_reference

Einstein's theory of special relativity likewise assumes the equivalence of all inertial reference frames, but makes a different additional assumption, namely, that the speed of light is the same when measured in all inertial reference frames.

And then...Hence, with respect to an inertial frame, an object or body accelerates only when a physical force is applied, and (following Newton's first law of motion), in the absence of a net force, a body at rest will remain at rest and a body in motion will continue to move uniformly—i.e. in a straight line and at constant speed.

Then, quite simply, light considered as the 'particle' and not the 'wave', meets the definition of being 'inertial' even in its own frame ;)

The actual theory and math says nothing about what space-time is made of. Only that it can be warped.

This is just flat wrong!

Originally Posted by Wiki
One of the core ideas of general relativity is that the metric (and the associated geometry of spacetime) is determined by the matter and energy content of spacetime. Einstein's famous field equations:

I fully understand that this was a natural thing to do, BUT as I have said repeatedly, Einstein DID NOT have enough information to actually make this statement as fact...he did not know about Non-Baryonic DM/Exotic Matter!

Here's the bold:

When ds2 = 0, the interval is lightlike,and can only be traversed by light.

What is your understanding of a lightlike interval?

Quote:
Originally Posted by RussT
That is where the light cones are seperated, and can have no causal effect, BUT the Exotic Matter can come our way, BUT nothing can go back that way, against 'space/time' coming to us. Don't thinking "Flipping" at the Ring Singularity...just space/time flowing to us at "c".

And beyond your say so, what proof do you have? The math says something different and I'll have to go with the math until you can provide something more than your say so.

Ya Got Me... actually I blew this one because I misread it...I thought it had said Non-light-like path...actually I was thinking more olonf the lines of causality must be within light cones scenario, and that wouldn't be true if "Exotic Matter" were traveling through a worm hole to us...there would be causality with NO light cone present. ;) I really shouln't have used it at all because I know that is not what this math is saying.

What is your definition of exotic matter?

I think you have read enough of my stuff to have a pretty good idea ;)
First, it is the 'extra gravity'/Exotic Matter that mainstream hypothesized as the answer for the rotation curves of the galaxies and the cluster dynamics.

And now comes a long and arduous discussion of the differences between HDM abd CDM, and why maintsream came up with the WIMP, and DM Halos, and "SIMS", and 200+ DM halos predicted for dwarf galaxies to be in, per galaxy, ETC, ETC...

BUT, since my initial correlation is that when our SMBH's are created, the High Energy Gamma Radiation that is produced is how the electrons/protons get their mass, that allows ne to think very differently about the Darkness and the initial conditions of the universe...SO, I made a very straight forward and what I think is a remarkable correlation...That the Non-baryonic Point Particle DM is Lisa Randall's "Leaking Gravity" from the 'other universe', it IS the 'extra gravity' and makes up ALL of 'space', is traveling at "c", and is the carrier of the EM waves.

That Exotic Matter traveling at "c", IS the inertial straight line motion in Every/All directions, that carries the light/photons and matches the defintion above perfectly. That is the "Particle" part of the lights 'wave' 'particle' duality.

You and Grey have dealt more with my work in progress over the last 2 years more than anyone else, and I do really appreciate your guys imput, teachings, sources, etc, and although I am sure you guys feel that I am just not getting it, I do have very good reasons, and extremely critical evaluations for coming to the stances that I have shown. I assure you that I am not just piecing together different terms and news bites in an incoherent jumble of misunderstood concepts, as you have seen me strongly object to.

SO, maybe this will make more sense to you and Grey when I explain the following.

There is a huge disconnect between GR and QM which centers on gravity, but more importantly how electrons/protons/neutrons get their mass.

One of the reasons that my concept of when our SMBH's are created, that that creates the High Energy Gamma Radiation, that then creates the electons/protons, is precisely the reason that the Extra Gravity being the point particles and Lisa Randall's 'leaking Gravity', is that when the Gamma radiation is expoding, the gravity particles are right their to get their mass.

In the Primordial universe, the electrons/protons/nuclei 'already' exist, and the collisions of all those equal amount of particles are what causes the Near Infinite GeV^19 Gamma radiation.

SO, in that scenario, the Gamma Photons are NOT causing the electrons/protons/nuclei to obtain their mass. Once cooled, the hydrogen can form with the already present helium, lithium, deuterium...that might not be exact, but is close, and really doesn't matter for else I am going to show.

Now, when the stars form, whether in galaxies or not, they start making what...oxygen, and whatever other ligher type elements (I know these are still considered metals) that stars make in their fussion processes. SO, what ever those elements are they get their 'extra mass' by the processes in stars combining different compound element structures of protons/neutrons.

The next heavier elements that are made all come through Super Nova's of all the diffeent types. SO, all the metals from carbon on up, are all made in these tremendously implosive/explosive events that again bind more types of proton/neutron combinations together.

Now, I know I am not telling you anything that you don't already know, SO what's the point to all this?

Think E=MC^2...when does light/photons from the UV all the way down to microwaves, EVER give any particles their "Gravity"???

And beyond your say so, what proof do you have?

And this line that you used above is quite telling. I am quite sure you probably meant to use the word 'evidence', which I feel I have provided a substantial amount, considering most of what I am showing has never even been considered or investigated in the way I am showing it...as an "Open System" but...this all pervasive 'show me the 'proof', and waving off, trivializing, dismissing anything that isn't in tune with the FLRW EFE paradigm is...somewhat understandable, BUT counter-productive, "IF" you are truely looking for answer to many of the biggest questions...like how do the base elements get their mass ;)

EvilEye
2007-Sep-02, 12:39 AM
So... after all this math and postulating... A simple yes or no answer should suffice.

If you rode a photon wave... would your trip be instantaneous or would you experience time?

I still think it would be like walking through a magical door. (meaning.. instantaneous)

Tensor
2007-Sep-02, 01:31 AM
So... after all this math and postulating... A simple yes or no answer should suffice.

Not quite.

If you rode a photon wave... would your trip be instantaneous or would you experience time?

Using SR it is neither. As Grey pointed out, SR does not allow a reference frame from the photon's point of view. If your velocity is c, you end up with a zero in the denominator. As a result, the equation is not defined. Now, if you want to extrapolate the change in the Lorentz factor, you would end up with the trip being instantaneous. But as Grey and I have pointed out, it really isn't valid, but it does get the point across.

I still think it would be like walking through a magical door. (meaning.. instantaneous)

Yep, pretty much. ;)

EvilEye
2007-Sep-02, 02:35 AM
I do understand that the photon is "from MY perspective" as old as the time it took to get to me from whence it left.

But isn't zero zero?

If I left on a ship and achieved the speed of light, Although I didn't notice it inside the ship, time would pass for me instantly. I would be the same age as I was when I left.

OR... are you saying that the twins, where one left at the speed of light and came back are the same age exactly, but the one that stayed only looks older?

Steve Limpus
2007-Sep-02, 09:06 PM

"I am driving my car at the speed of light and I turn on my headlights. What do I see?

Sadly this question and all others about experiences at the speed of light do not have a definitive answer. You cannot go at the speed of light so the question is hypothetical. Hypothetical questions do not have definitive answers. Only massless particles such as photons can go at the speed of light. As a massive object approaches the speed of light the amount of energy needed to accelerate it further increases so that an infinite amount would be needed to reach the speed of light.

Sometimes people persist: What would the world look like in the reference frame of a photon? What does a photon experience? Does space contract to two dimensions at the speed of light? Does time stop for a photon?. . . It is really not possible to make sense of such questions and any attempt to do so is bound to lead to paradoxes. There are no inertial reference frames in which the photon is at rest so it is hopeless to try to imagine what it would be like in one. Photons do not have experiences. There is no sense in saying that time stops when you go at the speed of light. This is not a failing of the theory of relativity. There are no inconsistencies revealed by these questions. They just don't make sense.

Despite these empty answers, nobody should feel too put down for asking such questions. They are exactly the kind of question that Einstein often asked himself from the age of 16 until he discovered special relativity ten years later. Einstein reported that in 1896 he thought:

'"If I pursue a beam of light with the velocity c (velocity of light in a vacuum), I should observe such a beam of light as a spatially oscillatory electromagnetic field at rest. However, there seems to be no such thing, whether on the basis of experience or according to Maxwell's equations. From the very beginning it appeared to me intuitively clear that, judged from the standpoint of such an observer, everything would have to happen according to the same laws as for an observer who, relative to the earth, was at rest. For how, otherwise, should the first observer know, i.e., be able to determine, that he is in a state of fast uniform motion? One sees that in this paradox the germ of the special relativity theory is already contained. Today everyone knows, of course, that all attempts to clarify this paradox satisfactorily were condemned to failure as long as the axiom of the absolute character of time, viz., of a simultaneous, unrecognizedly was anchored in the unconscious. Clearly to recognize this axiom and its arbitrary character really implies already the solution to the problem.'"

In 1905 he realised how it could be that light always goes at the same speed no matter how fast you go. Events that are simultaneous in one reference frame will happen at different times in another that has a velocity relative to the first. Space and time cannot be taken as absolute. On this basis Einstein constructed the theory of special relativity, which has since been well confirmed by experiment.

Questions of relative velocity in relativity can be answered using the velocity subtraction formula v = (w - u)/(1 - wu/c2). If you are driving at a speed u relative to me and you measure the speed of light in the same direction (w = c in my frame), the formula gives v the speed of light in your reference frame as, v = (c-u)/(1 - u/c). For any speed u less than c this gives v = c so the speed of light is the same for you. But if u = c the formula degenerates to zero divided by zero; a meaningless answer.

If you want to know what happens when you are driving at very nearly the speed of light, an answer can be given. Within your car you observe no unusual effects. You can look at yourself in your mirror which is moving with the car and you will look the same as usual. Looking out of the window is a different matter. The light from your headlights will always go at the speed of light in your reference frame. It will strike any object in its path and be reflected back. Everything else will be coming towards you at nearly the speed of light, so the light reflected from it will be Doppler shifted to very high frequencies--towards the ultraviolet or beyond. If you have a suitable camera you could take a snapshot. The objects passing are contracted in length but because of the different times of passage for the light and effects of aberration, the snapshot will show the objects you pass as rotated."

© 1992--2006 by Scott Chase, Michael Weiss, Philip Gibbs, Chris Hillman, and Nathan Urban.

Steve Limpus
2007-Sep-02, 10:58 PM
Ya gotta like this passage!

http://www.btinternet.com/~j.doyle/SR/Sr6/sr6.htm

"In 1905 Albert Einstein was working as a patent clerk in Switzerland. He always claimed he new nothing of the Micheson and Morely experiments and this is quite possibly true. Einstein's physics were usually carried out without reference to experimental results. Instead he relied on his own intuition. His isolation from the physics community was probably a bonus in that he was allowed to think freely without being swayed by contemporary ideas or doctrine.

Einstein started by asking the almost child-like question "what would it be like to ride on a light beam?". The answer to this simple question eventually led him to deduce his theory of relativity. In order for his ideas and equations to make any sense he had to do something no one had dared to do before; he had to accept the constancy of the speed of light at face value. Once this is done the constancy of the speed of light is one of only two postulates needed for the whole of special relativity:

Postulate 1: The principle of relativity.
The laws of physics are the same in all inertial frames.

Postulate 2: The principle of the constancy of the speed of light.
The speed of light (in a vacuum) has the same constant value 'c' in all inertial frames.

The whole of special relativity; time dilation, the twin paradox, moving clocks running slowly, space-time and everything else all stem from just these two postulates. Once the speed of light is accepted as a constant, as it had already been seen to be both in theory and experiment, everything slots into place. That the speed of light is constant has been checked over and over again using ever more sophisticated equipment.

Probably the most startling demonstration of the second postulate being correct is the detonation of an atomic bomb. Whatever one thinks of the merits of such devices it is undeniable that they work. The basic principle behind an atomic bomb is that matter is converted into energy via the famous equation E = mc2. This equation is derived directly from the second postulate. There are few more convincing ways in which a "theory" can be demonstrated to be correct."
J.K. Doyle

Einstein was The Man!

Steve Limpus
2007-Sep-03, 01:46 AM
So, what if it were possible to build a rocket which could accelerate constantly at 1g?

Doesn't sound like TOO big an ask. :whistle:

How long would it take to get around?

Rocket years: 2.34 Earth Years: 5.127 --Proxima Cen (nearest star)
Rocket years: 10.9 Earth Years: 2.7x104 --Centre of Milky Way
Rocket years: 15.4 Earth Years: 2.4x106 --Andromeda (nearest galaxy)
Rocket years: 25.3 Earth Years: 5.0x1010 --Edge of Observable Universe

What a trip THAT would be! Here's the thing:

"Firstly, it would take a huge amount of energy to keep you accelerating at g. Secondly, by the time you got back, not only would all your friends and family be dead, but the Earth would probably be gone, swallowed by the Sun in its red giant phase, the Sun would have exhausted its fuel and shrivelled into a cold white dwarf star, and the Solar System, having orbited the Galaxy a thousand times, would be lost somewhere in its milky ways."

So the mileage is lousy and the return trip a real downer. :sad:

Would you go faster than light? :naughty:

"No. From the point of view of a person at rest on Earth, you never go faster than the speed of light. From your own point of view, distances along your direction of motion are Lorentz-contracted, so distances that are vast from Earth's point of view appear much shorter to you. Fast as the Universe rushes by, it never goes faster than the speed of light."

Are we there yet? :doh:

"The Universe is expanding, so the distance to the edge of the currently observable Universe is increasing; it would actually take longer to reach the edge of the currently observable Universe. And if the Universe is accelerating, then you will never be able to reach the edge of the currently observable Universe, however fast you go."

RussT
2007-Sep-03, 10:57 AM
Tensor, you keep taking just the quotes you want to use, out of context of how I was showing different correlations.

These are my posts
http://www.bautforum.com/1062719-post3.html

http://www.bautforum.com/1062876-post14.html

This is yours
http://www.bautforum.com/1062963-post18.html

Let''s look at the equations:

g = 1/sqrt(1- v^2/c^2), where g is the gamma factor, v is the velocity in question and c is, of course the speed of light. If you put the speed a photon is moving into v you end up in the denominator, under the square root with this: 1-c^2/C^2, which reduces to 1-1. This leaves you with a zero in the denominator and division by zero is undefined.

YOU seem to think that this Math IS the theory and 'proves' something.

YOU, keep accusing me of NOT understanding the theory, and that any explanation MUST be lacking if I say the theory is wrong, because you automatically think the Maths must be right...That's NOT it!!!

IT is that the Maths are NOT being applied correctly to lights own frame...light along its own path.

When you get to the 'division by 0'...Infinity, that's when you know that something MUST be different to correctly correlate 'what is happening there', Just like at r=0 in Black Holes.

Which does not mean light travels instaneously or takes no time.

Really?

It means the equations are undefined.

Again, Really?

THEN, why does the definition of...'light is simultaneous at all points along its Path to Infinity, or source to sink' appear in the definition of light in its own frame?

AND, why is Time frozen at the event horizons of Black Holes, so that from our frame of reference, it appears that they can never even form?

Those are both rhetorical questions, because the answer is that they are both....Impossible.

Well since the equations at c are undefined, there's no way to define it as a frame of reference.

Sure there is. It just hasn't been done yet because everyone/mainstream has been SOOOOO convinced that time dilation and Lorentz Contraction MUST be true.

You just have to set the 'wave' part at 0 velocity and the 'particle' part at "c" in a dimensionless background space.

But, the simple fact is, that when Lorentz and Einstein put in the variables of time dilation and Lorentz contraction, and THEN got to your above Maths, where they had to define light in its own frame as...simultaneous at all points along its own path to Infinity, to make the variables work, with the result that Mr Spaceman could then travel to the end of the universe "Instantly", OR that light in its own frame could do the same, EVERYONE should have known that it had to be WRONG.

Which means that the .99/.8/.6 dilation/contractions are also WRONG

EvilEye
2007-Sep-03, 04:50 PM
Too bad with all these great ideas, that Hawkings won't come here and tell us what's what.

But then.. would it mean he was right either?

Steve Limpus
2007-Sep-05, 01:10 AM
Too bad with all these great ideas, that Hawkings won't come here and tell us what's what.

I once tried to read a A Brief History of Time--my head has hurt ever since...

... so I'm not sure Hawking could help! :eh:

Did like this though:

"... if we do discover a complete theory, it should in time be understandable in broad principle by everyone, not just a few scientists. Then we shall all, philosophers, scientists, and just ordinary people, be able to take part in the discussion of the question of why it is that we and the universe exist. If we find the answer to that, it would be the ultimate triumph of human reason - for then we would know the mind of God."
S.W. Hawking

Appeals to my sense of the awesome.

Steve Limpus
2007-Sep-05, 01:21 AM
"Einstein once asked the question: '"How much choice did God have in constructing the universe?'" Even if there is only one possible unified theory, it is just a set of rules and equations. What is it that breathes fire into the equations and makes a universe for them to describe?... Why does the universe go to all the bother of existing? Is the unified theory so compelling that it brings about its own existence? Or does it need a creator, and, if so, does he have any other effect on the universe? And who created him?"
S.W. Hawking

"Whoa..."
Neo

EvilEye
2007-Sep-05, 01:46 AM
"We are a way for the universe to know itself."

-Carl Sagan "Cosmos"

Tensor
2007-Sep-05, 02:26 AM
Tensor, you keep taking just the quotes you want to use, out of context of how I was showing different correlations.

These are my posts
http://www.bautforum.com/1062719-post3.html

From that quote:
And, I am saying that Einsteins defining of light as simultaneous at all points along its path to infinity, and photons experiencing NO TIME in its own frame, and THEN determining that light in its own frame is NOT a valid inertial frame, is the mathematical culprit of all of this...

No where does Einstein say (and that goes for me also) that light is simultaneous at all points. As you have constantly been told, The no time in lights own frame is nothing more than a simplified explanation.

http://www.bautforum.com/1062876-post14.html

This whole post is nothing more and an excellent example of the way you try to do physics by quotes, and not the math.

This is yours
http://www.bautforum.com/1062963-post18.html

Yep, where I specifically say that it is nothing more than a simplified explanation and can't be used to show a inconsistency in relativity. If you want to do that, you will have to show where it's inconsistent, IN THE MATH. Something you have yet to do.

YOU seem to think that this Math IS the theory and 'proves' something.

YOU, keep accusing me of NOT understanding the theory, and that any explanation MUST be lacking if I say the theory is wrong, because you automatically think the Maths must be right...That's NOT it!!!

Yes it is, I'm not the only one, get over it. Until you can show me something wrong with the math.

IT is that the Maths are NOT being applied correctly to lights own frame...light along its own path.

When you get to the 'division by 0'...Infinity, that's when you know that something MUST be different to correctly correlate 'what is happening there', Just like at r=0 in Black Holes.

Why? Why can't it just be the division between timelike and spacelike paths? Which would mean is neither spacelike or timelike. It's even simpler in the four-vector formalization of SR in Minkowski space. The lightpath is known as a null vector. This is because the four-vector for light is a zero length vector.

Really?

Yes really.

Again, Really?

Again, Yes really.

THEN, why does the definition of...'light is simultaneous at all points along its Path to Infinity, or source to sink' appear in the definition of light in its own frame?

You keep saying this, where is that definition exactly? If it's not in Einstein's paper or in Minkowski's four-vectors, then it's nothing more than you taking a simplified explanation (that doesn't actually agree with the theory) and trying to use it. It's basically you doing your "physics by quote" again.

AND, why is Time frozen at the event horizons of Black Holes, so that from our frame of reference, it appears that they can never even form?

You obviously still haven't found the answer, even after I gave you a hint.

Those are both rhetorical questions, because the answer is that they are both....Impossible.

Well, since you obviously haven't found and don't know about the second and no one has claimed the first (except for your attributing it to the mainstream, even though the mainstream doesn't claim that) you obviously don't understand even SR, your claims of understanding not withstanding.

Sure there is. It just hasn't been done yet because everyone/mainstream has been SOOOOO convinced that time dilation and Lorentz Contraction MUST be true.

Well, with these tests (http://math.ucr.edu/home/baez/physics/Relativity/SR/experiments.html) showing how much experimental evidence supports both time dilation and Lorentz contraction (I really don't like the contraction name as for a real three dimensional object it is a rotation rather than a contraction) you obviously haven't done much researched as to exactly why SR is so accepted.

You just have to set the 'wave' part at 0 velocity and the 'particle' part at "c" in a dimensionless background space.

LOL, wave part, particle part? You obviously don't even have a full grip on wave particle duality. This statement doesn't even make sense, from a QED and SR perspective. What exactly do you consider a dimensionless backround space?

But, the simple fact is, that when Lorentz and Einstein put in the variables of time dilation and Lorentz contraction,

More math misunderstanding. Einstein did not put them in, they were derived using the rules of math. That's what made Einstein's SR better than Lorentz's.

and THEN got to your above Maths, where they had to define light in its own frame as...simultaneous at all points along its own path to Infinity, to make the variables work,

Buzz, wrong, thank you for playing. Show me one place in Einstein's paper where it defines light as simultaneous in it's own path.

Which means that the .99/.8/.6 dilation/contractions are also WRONG

Instead of ranting about what you think is wrong, how about showing some of the math that is wrong. I gave you a large example of the tests that SR has been put through. Feel free to show where those tests and the math are wrong. I would point out two places where SR is working every day. One, in all the particle accelerators and two, anytime someone uses a GPS. If the math was so wrong, neither or those (or any of the other tests,) would work. What you are doing is nothing more than I could do by claiming a pink fairy's wand is respnsible for all the dilation and rotation in SR.

RussT
2007-Sep-09, 08:41 AM
I have thought long and hard on how to respond to this.

With all due respect, and much appreciation, for all the time you and Grey have spent with me over the last 2 years, trying to show how 'false negatives' wrong is NOT an easy task.

Your entire post is aimed at one thing...discrediting, dismissing, trivialization, and theory protecting.

I have already stipulated that the Maths are 'to crap your pants for' purr-fect.

AAAAAAND, you just keep ignoring all the posts and quotes where I have shown that light in its own frame is 'inertial'...by definition!

AND, we know that light travels at 186,000 mpsecond, SO there is absolutely no reason to assign it a 0 speed/constant velocity, even in its own frame...accept of course to make time dilation and Lorentz contraction/rotation "FIT"!

I have also shown that seeing 'reality' from a 'stationary'/'rest frame' is NOT "REALITY"...to see 'what is really happening there', you have to go to the other frame, and figure out what is really happening 'there'!!!

SO, somehow, Einstein, with excellent Maths and logic, was able to convince mainstream, that seeing 'reality' from a 'rest frame' was acceptable...and since ALL the Maths work SO perfectly, it has been accepted for over 100 years. Which unfortunately means that ALL the 'tests' that show SR works in the 'stationary frame'/rest frame, are NOT seeing reality...so, just like I explained for the Rebka/Pound experiment...it is the earths rotation that causes the stretching of the gamma rays, NOT gravity.

SO, basically, a whole cosmology has been developed based on what little green aliens would 'supposedly see' were they able to flit around the universe in their spaceships at relavistic velocities.

Yes, light is constant at 186,000 mps in Vacua, from ALL reference frames, BUT the consequence of light being constant at "c" is NOT time dilation or Lorentz contraction.

SO, when the end result of assigning simultaneity to all photons in their light path, in lights reference frame, and 0 time that a photon experiences, in its own frame, results in photons/light being able to travel to infinity, instantly, in its own frame, YA gotta know that that is Impossible.

For special relativity, there is no reference frame in which light can travel an infinite distance instantly. That's true whether we're using "classical" special relativity and treating light as a wave, or quantum electrodynamics (which incorporates special relativity), in which light can be considered to be composed of photons. If you want to create your own theory, where it is possible to have the rest frame of a photon, that might be a problem for your theory, but that doesn't make it so for relativity.

And back on page 3, Grey responded to my above post with this.

AND, this is my main point...to define light, in its own frame as having 0 velocity and experiencing no time, which in effect, says that light, in its own reference frame can go from source to sink "Instantly", AND THEN, just saying that light in its own frame is NOT a VALID reference frame is...Not Even Wrong.

WE KNOW that it travels at 186,000mps. They/You cannot just set light and time to 0, and then thrown in variables to 'fIT' what they are trying to do mathematically.

Originally Posted by RussT
and THEN got to your above Maths, where they had to define light in its own frame as...simultaneous at all points along its own path to Infinity, to make the variables work,

Buzz, wrong, thank you for playing. Show me one place in Einstein's paper where it defines light as simultaneous in it's own path.

See, this is what I am talking about...whether Einstein put this specifically in his papers or not, you and I both know that assigning 0 velocity to light in its own reference frame, has the exact effect of making it go from source to sink OR INFINITY
instantly!

Feel free to show where those tests and the math are wrong.

As I have stated numerous times now, the MAth isn't wrong......it perfectly valid...the interpretation that you are seeing 'reality' from the 'rest frame' is WRONG.

This whole thing is about trying to prove a 'false negative' wrong.

Maybe this from post #59 is the answer to what is wrong...

“Natural” coincidence is otherwise known as a spacetime point. Einstein has already spent twenty-odd pages of this very brief book laying out the assumptions which underlie the train experiment. He is very careful about being consistent with them, and he is a devoted and very strict Euclidean. But Einstein was not, it appears, quite careful enough. We know that he is assuming, along with Euclid, that the definition of the coincidence of two points is a point. However, we have never gotten (and never get, in any of Einstein’s writings) a definition of a “natural” coincidence of two points. This alone prevents us from going on and this argument, which defined the twentieth century, abruptly ends. We also have a problem if we try to resolve the issue ourselves. If we simply drop the term “naturally” we run into a situation in which Einstein has told us to assume two Cartesian coordinate systems, but now leaves us with one, since, following from the definition of the coincidence of two points, if two parallel coordinate systems coincide at one point, they coincide at all points and are one coordinate system, not two. We have been led to a contradiction. My Bold/Red

The seeing reality from the 'rest frame' is the problem interpretation wise, so the bold is possibly the answer math wise, which I started thinking along the lines of when following the 1=2 threads.

Plus, "possibly" what two ships would see, would be to be able to verify what the 'other frame' is actually seeing, VS trying to 'convert it' to our rest frame to 'see' and not agree with the 'other ship', if that even makes sense (and If that is NOT pure SCI-FI and absolutely unrealistic in ways we don't even know!!!).

I don't even know if using ships at relavistic velocities is something that makes any sense what-so-ever, and like CM said....his Angels are not going to be making their test flights anytime soon ;)

BUT, think about this...setting light and time to 0, and THEN not wanting to count that as a valid reference frame, is basically the same thing that is done with the naked singularity in the Big Bang....it took me a years and 1/2 to get you to even agree that the naked singularity was even considered part of the Big Bang theory.

SO, you/they define the universe as starting from a 'Point'/naked singularity, everywhere the center of a finite but unbounded universe, basically setting everything to 0..a point that they can only get to within T=10^43 of, BUT think they need to get to T=0, and THEN say, oh that is not even part of the theory...it doesn't count, just like the defined 0 velocity/time for light in its own frame doesn't count either.

This, whether you want to believe it or not, is a very definitive, critically derived, self consistent and Coherent statement...

Besides, as I have shown, nothing can 'come through' a "POINT", which is what the current 'naked singularity' is...just a Point at T=10^-43. AND IF the the E-R Bridge is correct, THEN there is no need to get from T=10^-43 down to T=0, and r=0 just becomes the center of the "Point Particle". If you understand what this is really showing.

I keep thinking that if I show something definitive "Enough" that someone will say....you know, he just might be on to something here, we should investigate this thoroughly!!!

BUT, that is NOT going to happen, as far as I can see, because the more I have determined, the more wrong things I have found in the current paradigm. which is devastating for science because they have defined/made Laws for everything in a 'closed system'!

I have now determined two more substancial correlations, one about Galctic Bulges/Xrays/SMBH's across the universe and the other about...
Quote:
But trying to pin down the nature of dark energy has proven extremely difficult. Theories of particle physics suggest that space does have an inherent energy, but this energy is about 10^120 times greater than what is actually observed.

This second correlation will be pretty hard to just wave off and sweep under the table, BUT, I suspect that it will be done anyway :)

I will show those tomorrow in another thread where a conversation had taken place that would fit that.

jrysk
2007-Sep-11, 06:01 PM
The flaw--from Wikipedia

--------------------------------------------------------------------------------

 Natural mathematics, Einstein's "practical geometry" and the Ryskamp objection of "natural" coincidence

Note that the metrical interpretation of the 1905 paper disguises, but does not avoid, the "natural" coincidence of points M' and M ("fallt zwar...zusammen") which Einstein, following the program of natural mathematics which he had adopted from Poincare's SCIENCE AND HYPOTHESIS (1902), put in the train experiment in his book RELATIVITY (1916). This work receives little attention from scholars because it is regarded as a popularization. However, Einstein valued it highly and recently it has been claimed as the clearest exposition of the relativity of simultaneity--of "practical geometry," which was Einstein's term for natural mathematics.

(remaining quoted material deleted by Moderator for possible copyright infringment)

tonyman1989
2007-Sep-15, 12:50 PM
So... after all this math and postulating... A simple yes or no answer should suffice.

If you rode a photon wave... would your trip be instantaneous or would you experience time?

I still think it would be like walking through a magical door. (meaning.. instantaneous)

Yes and No.

Let say your trip was one light year it would take one year for the light to go from point a to point B, but it would feel instantaneous to you.

Wikipedia explains his pretty well http://en.wikipedia.org/wiki/Time_dilation

macaw
2007-Oct-26, 05:58 PM
The appearance of a contraction is a artifact of the simplifying done to explain it. Most of the time, the explanation is only presented in one dimension. One dimensionally, the object would appear, to an observer, to contract. Realistically, if you were able to view an actual three demensional object traveling relativistically, it would appear to be rotated, not contracted. This is due to the combination of the speed and the different light paths from the front and rear of the object to the observer. "Spacetime Physics" by Wheeler and Taylor (http://www.amazon.com/Spacetime-Physics-Edwin-F-Taylor/dp/0716723271/ref=pd_bbs_1/002-0350473-8004036?ie=UTF8&s=books&qid=1181090785&sr=1-1), has an excellent explanation of the effect.

Yes, it is called Penrose-Terrell effect, I think wiki has a pretty good page on it as well.