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Squashed
2006-Oct-09, 01:43 AM
Since the speed of light is the absolute fastest speed then doesn't that define an absolute reference frame since all velocities must fall between zero and the speed of light?

If we could determine our speed relative to the speed of light then would that prove that there is an absolute reference frame? (I personally do not believe in an "ether" or geocentrism - so don't think I am advocating either of these ideas.)

The "perfect" clocking device is the light-reflection clock of thought experiment fame but it seems that it is only accurate as long as time is measured by the round-trip path of light. By round-trip I mean the light must start at one mirror then travel a one-way segment to reflect off the other opposing mirror for a second one-way segment which returns the light to the first mirror again (a round-trip between the mirrors).

I have been pondering trying to use a setup of mirrors so that I can compare the two one-way times that compose the round-trip but have had no luck so far because every ingenious idea I have ends up being composed of just multiple round trips.

Thanks for any input in regard to the above - I am still working on some ideas but will not be able to post for a couple days.

publius
2006-Oct-09, 01:49 AM
Squashed,

Since the speed of light is c to all observers (in flat space-time, and to all time-orthogonal observers in curved space-time at least...don't ask...), then our speed relative to light is always c, at least from our respective. The "light frame" doesn't qualify as a reference frame -- we can't imagine ourselves moving at light speed, following a null geodesic. The "null" part means 0 proper time (stopped clock) and things break down trying to define a reference frame along such a null path.

-Richard

Jeff Root
2006-Oct-09, 05:32 AM
Squashed,

Can you explain what you meant by the expression, "our speed
relative to the speed of light"?

-- Jeff, in Minneapolis

Squashed
2006-Oct-10, 01:22 PM
Squashed,

Can you explain what you meant by the expression, "our speed
relative to the speed of light"?

-- Jeff, in Minneapolis

Jeff, If you study this picture (http://www.bautforum.com/showpost.php?p=840326&postcount=37) you can see that since the speed of light is constant the velocity of the moving mirrors allows the light to travel in one direction longer than the other direction.

The sum of the round trip results in an accurate clocking mechanism but in order to determine who is actually moving in a deep space situation the only common reference frame is the speed of light.

According to relativity neither vehicle in a deep space encounter should be able to tell who is moving because they only have each other to reference off of ... but I think it is possible to tell who is moving fastest.

I think this picture (http://www.bautforum.com/attachment.php?attachmentid=3703&stc=1&d=1160488880) should make it quite clear how to tell a vehicle's speed relative to the speed of light.

The two distances shown are the two one-way distances that the light travels when bouncing between the two mirrors at the speed of 0.8c and with the stationary distance between the mirrors at 1.0 light-second apart (which is length contracted to only 0.6 light-second apart).

Since the light is unaffected by the movement of a space vehicle then I propose that a simple rotatable spotlight and wall arrangement be used to determine the vehicle's speed relative to the speed of light.

As you can see in this picture (http://www.bautforum.com/attachment.php?attachmentid=3703&stc=1&d=1160488880) (the blue lines represent walls and the white lines represent a beam of light) if the spotlight and wall are aligned with respect to the movement and in the direction of the movement the spot on the wall will be big ... If aligned to point in the opposite direction the spot on the wall will be small. The ratio of spot sizes can be used to determine the speed of the vehicle with respect to the speed of light.

(I show circles to represent the spot sizes ... the circles are rotated 90 degrees from the wall arrangement.)

It can also be noted that the intensity of the light can be measured since the longer path allows the light to disperse more than the shorter path.

Jeff Root
2006-Oct-10, 03:20 PM
Hoo boy.

-- Jeff, in Minneapolis

Jeff Root
2006-Oct-10, 03:34 PM
Squashed,

Please try again. I'm going to add a step:

First, explain what is meant by "the speed of light".
That should be easy, since your explanation should be
equivalent to that of anyone else.

Then explain what you mean by the expression,
"our speed relative to the speed of light". That may
be more difficult, since it is unique to you.

-- Jeff, in Minneapolis

Bearded One
2006-Oct-10, 04:15 PM
I think this picture (http://www.bautforum.com/attachment.php?attachmentid=3703&stc=1&d=1160488880) should make it quite clear how to tell a vehicle's speed relative to the speed of light.

The two distances shown are the two one-way distances that the light travels when bouncing between the two mirrors at the speed of 0.8c and with the stationary distance between the mirrors at 1.0 light-second apart (which is length contracted to only 0.6 light-second apart).

I think you need to rephrase that.

I believe you are saying that you have 2 mirrors, one light second apart, that are moving away from an observer at 0.8c. the mirrors seem to be aligned with the direction of travel relative to the observer. So why are you saying (in the picture) that they are 3.33 light seconds apart?

I think you might be mixing up your reference frames.

01101001
2006-Oct-10, 04:23 PM
I think you might be mixing up your reference frames.

Ya think?

That's been a fundamental theme of this series.

Squashed
2006-Oct-10, 04:26 PM
I think you need to rephrase that.

I believe you are saying that you have 2 mirrors, one light second apart, that are moving away from an observer at 0.8c. the mirrors seem to be aligned with the direction of travel relative to the observer. So why are you saying (in the picture) that they are 3.33 light seconds apart?

I think you might be mixing up your reference frames.

I'm sorry if it is confusing (it's clear as day to me ... in my mind).

What that picture shows is the amount of distance the light travels per one-way trip between the mirrors.

Since the mirrors are moving and aligned on the vector of movement then the velocity of the ship containing the light-reflection clock causes the distance traveled by the light to be different for each direction of travel.

Since the ship's velocity can not affect the light then it must spread out as it travels (it is a spotlight not a laser) and so since it goes farther in one direction than the other then the light naturally makes a bigger spot in one direction than the other.

The observer is on the ship - this is a method for a traveler to determine their speed in relation to the speed of light - which is always c or 299,792,458 meters per second in all reference frames.

SeanF
2006-Oct-10, 05:02 PM
Hi, Squashed! Sorry for not getting back to that other thread - I had a busy weekend.


... the speed of light ... is always c or 299,792,458 meters per second in all reference frames.
You say this, but I don't think you understand what it really means.

It means that for the observer on the ship - who sees the ship as stationary - the light would take the same amount of time to go both directions. It is only for the off-ship observer - who sees the ship as moving - that the directions have different distances (and times).

Bearded One
2006-Oct-10, 05:26 PM
Since the mirrors are moving and aligned on the vector of movement then the velocity of the ship containing the light-reflection clock causes the distance traveled by the light to be different for each direction of travel.

Since the ship's velocity can not affect the light then it must spread out as it travels (it is a spotlight not a laser) and so since it goes farther in one direction than the other then the light naturally makes a bigger spot in one direction than the other.

The observer is on the ship

So, the mirrors are stationary relative to each other? The ship is moving away from them at 0.8c at a vector aligned with an axis through the mirrors?

Now, this light beam is bouncing between the two mirrors and it's travel time is being measured from the guy on the ship? Have I got that right?

Squashed
2006-Oct-10, 06:52 PM
So, the mirrors are stationary relative to each other? The ship is moving away from them at 0.8c at a vector aligned with an axis through the mirrors?

Now, this light beam is bouncing between the two mirrors and it's travel time is being measured from the guy on the ship? Have I got that right?

You seem to have it pretty much correct except the light-reflection clock (mirrors) is on board the ship.

The ship is traveling down the X-axis and both mirrors are on the X-axis and the light is reflecting back-and-forth along the X-axis.

If the mirrors and reflecting light were perpendicular to the direction of travel then the spotlight spots would both be the same size - this would tell the ship captain to rotate the assembly until the spotlight spot sizes began to differentiate.

The scale used, light-seconds, can be scaled down to practical sizes and the effect would be the same ... I just used these sizes because they work out to round numbers and they are useful for teaching about length contraction and relativity.

The whole idea stems from the fact that angles should be preserved even at relativistic speeds and also because after the photon has left the emitter the ship can no longer influence the photon's travels.

The light cone continues to grow as the distance the light travels increases.

Also the intensity of the light decreases with distance according to the inverse square law - another measureable effect.

SeanF
2006-Oct-10, 07:17 PM
The whole idea stems from the fact that angles should be preserved even at relativistic speeds and also because after the photon has left the emitter the ship can no longer influence the photon's travels.
Angles are not preserved at relativistic speeds.

The photon travels at the speed of light relative to the ship for observers on the ship.

Squashed
2006-Oct-10, 07:30 PM
Angles are not preserved at relativistic speeds.

The photon travels at the speed of light relative to the ship for observers on the ship.

The angle of the light cone produced by the spotlight is preserved because it is made by the light not the ship.

Also you could argue that due to length contraction the spotlight reflector angle would open up but this would be true if you pointed it down the positive X-axis or the negative X-axis.

The travelers can only measure the round-trip speed of light not the one-way speed.

SeanF
2006-Oct-10, 07:51 PM
The angle of the light cone produced by the spotlight is preserved because it is made by the light not the ship.
No, it's not.

Let's say the room is square. You put one mirror in one corner and the other mirror in the opposite corner.

When the room is stationary, the light needs to move at a 45 degree angle to the walls of the room in order to get from one mirror to the other.

When the room is in motion, that angle will be different - greater than 45 degrees in one direction and less than 45 degrees in the opposite direction.

Otherwise the light wouldn't hit both mirrors. It does, thus the angles must change from one reference frame (room is stationary) to the other (room is in motion).

EDIT: Changed an "other" to an "opposite."

Jeff Root
2006-Oct-11, 05:28 AM
Squashed,

Please explain what you mean by the expression,
"our speed relative to the speed of light".

-- Jeff, in Minneapolis

Squashed
2006-Oct-11, 12:07 PM
No, it's not.

Let's say the room is square. You put one mirror in one corner and the other mirror in the opposite corner.

When the room is stationary, the light needs to move at a 45 degree angle to the walls of the room in order to get from one mirror to the other.

When the room is in motion, that angle will be different - greater than 45 degrees in one direction and less than 45 degrees in the opposite direction.

Otherwise the light wouldn't hit both mirrors. It does, thus the angles must change from one reference frame (room is stationary) to the other (room is in motion).

EDIT: Changed an "other" to an "opposite."

Isn't that a thought experiment or has it actually been proved?

Light has certain one-way qualities which are the fact that the light cone from an emitter continues to enlarge as the distance from the emitter increases - this also leads to the fact that the intensity of the light decreases with increasing distance. Even Einstein himself recognized this fact when in his 1905 paper he did the calculations and stated:

"It follows from these results that to an observer approaching a source of light with the velocity c, this source of light must appear of infinite intensity."

Technically the mirrors composing the light-reflection clock are sources of light because the atoms absorb the photons and then re-emit them in the opposite direction.

I propose that we can use this one-way characteristic of light to tell our speed in relation to the speed of light. If my spaceship is traveling at 0.5c and there are no external reference points then I can always resort to the speed of light as a reference to determine my speed - Jeff, does this answer your question?

Jeff, I might add that the reference frame using the speed of light does not have an origin or direction to it (that I can imagine) - the speed of light can only be referenced to determine the ratio of your speed to the speed of light. If we are traveling at 300 km/sec then the ratio would be 300/300,000,000

Squashed
2006-Oct-11, 12:57 PM
No, it's not.

Let's say the room is square. You put one mirror in one corner and the other mirror in the opposite corner.

When the room is stationary, the light needs to move at a 45 degree angle to the walls of the room in order to get from one mirror to the other.

When the room is in motion, that angle will be different - greater than 45 degrees in one direction and less than 45 degrees in the opposite direction.

Otherwise the light wouldn't hit both mirrors. It does, thus the angles must change from one reference frame (room is stationary) to the other (room is in motion).

EDIT: Changed an "other" to an "opposite."


SeanF, for a typical spotlight there is a reflector that directs the light and this reflector has a reflector angle - this angle will be affected by length contraction ... but the effect will be equivalent if the spotlight is aligned along the direction of travel: see attached image (http://www.bautforum.com/attachment.php?attachmentid=3717&stc=1&d=1160571366).

The reason the spotlight will make different size spots on the wall is because the light travels different distances, depending upon whether it is pointed down the positive X-axis or the negative X-axis.

SeanF
2006-Oct-11, 01:52 PM
Isn't that a thought experiment or has it actually been proved?
Well, the way I described it is a thought experiment - nobody's ever actually accelerated a square room to relativistic velocities. :D

However, the Michelson-Morely experiment (and others like it) have verified that the Earth's motion in it's orbit around the sun can not be detected by a light-device being tested first parallel to the orbital plane and second perpendicular to it.

So that's basically the same thing.

Squashed
2006-Oct-11, 02:19 PM
Well, the way I described it is a thought experiment - nobody's ever actually accelerated a square room to relativistic velocities. :D

However, the Michelson-Morely experiment (and others like it) have verified that the Earth's motion in it's orbit around the sun can not be detected by a light-device being tested first parallel to the orbital plane and second perpendicular to it.

So that's basically the same thing.

In the M-M experiment did they use a one-way set-up or did the light end up traveling a round trip (I could not figure out a way to measure the one-way trip time, using mirrors)?

A quick cursory glance at some of the set-ups depicted on the internet makes me believe the light is traveling round-trips which would negate any interference because round-trips always produce accurate clocking.

-------

If the one-way travel distance is truly different as your calculations (http://www.bautforum.com/showpost.php?p=839544&postcount=25) require it to be then the following should be detectable:

A photon detector on the back wall of the spacecraft (traveling at 0.8c) would detect 81 times more photons per unit of time than when the photon detector is placed on the front wall of the spacecraft (just rotate the same spotlight 180 degrees, from pointing at the back to pointing at the front).

SeanF
2006-Oct-11, 02:30 PM
In the M-M experiment did they use a one-way set-up or did the light end up traveling a round trip (I could not figure out a way to measure the one-way trip time, using mirrors)?
There really isn't any way to measure the one-way trip time, which is why I said in the other thread you have to use round-trip time to measure time. :)

Here's (http://en.wikipedia.org/wiki/Michelson-Morley_experiment) a history and description of the M-M experiment.

Jeff Root
2006-Oct-11, 02:57 PM
I propose that we can use this one-way characteristic of light to
tell our speed in relation to the speed of light. If my spaceship is
traveling at 0.5c and there are no external reference points then
I can always resort to the speed of light as a reference to
determine my speed - Jeff, does this answer your question?
No. You have repeatedly described a simple geometric effect
that you think should occur, but you have not explained what
you mean by "our speed relative to the speed of light".



Jeff, I might add that the reference frame using the speed of light
does not have an origin or direction to it (that I can imagine) - the
speed of light can only be referenced to determine the ratio of
your speed to the speed of light. If we are traveling at 300 km/sec
then the ratio would be 300/300,000,000
You did what I frequently do and mixed meters and kilometers.
You meant 300/300,000, or 1/1,000.

That is just a ratio of two speeds, which doesn't tell you anything
new or particularly interesting.

-- Jeff, in Minneapolis

Squashed
2006-Oct-11, 03:08 PM
No. You have repeatedly described a simple geometric effect that you think should occur, but you have not explained what you mean by "our speed relative to the speed of light".

Since the speed of light is independent of the speed of the emitter (some experiment proved this) then it does not matter what speed the spotlight is traveling because the photons will always travel at the speed of light.

The only speed that can vary (in this thread) is the speed of the spacecraft which is always a multiple of the speed of light, whether the spacecraft speed is:

0*c=0

or

1*c=c

or some value in between.



You did what I frequently do and mixed meters and kilometers.
You meant 300/300,000, or 1/1,000.

That is just a ratio of two speeds, which doesn't tell you anything
new or particularly interesting.

-- Jeff, in Minneapolis

Thanks for the correction.

Squashed
2006-Oct-11, 03:12 PM
There really isn't any way to measure the one-way trip time, which is why I said in the other thread you have to use round-trip time to measure time. :)

Yeah, after you posted that I spent several days worth of spare time trying to figure out a way.




Here's (http://en.wikipedia.org/wiki/Michelson-Morley_experiment) a history and description of the M-M experiment

Looking at the simple diagram (http://en.wikipedia.org/wiki/Image:Michelson-morley.png) they give it is easy to see that the light makes complete round trips and so no interference should be expected.

Jeff Root
2006-Oct-11, 03:14 PM
Squashed,

I can measure my speed relative to point A by measuring the
distance from me to point A at one instant, then measuring
the distance again at another instant, subtracting to get the
difference, and dividing by the time interval. For example, the
first distance might be 10 meters, and the second distance
might be 50 meters, and the time interval might be 1 second.
That gives a speed of 40 meters per second. That is my speed
relative to point A.

Now you describe my speed relative to the speed of light.

-- Jeff, in Minneapolis

Squashed
2006-Oct-11, 03:32 PM
Squashed,

I can measure my speed relative to point A by measuring the
distance from me to point A at one instant, then measuring
the distance again at another instant, subtracting to get the
difference, and dividing by the time interval. For example, the
first distance might be 10 meters, and the second distance
might be 50 meters, and the time interval might be 1 second.
That gives a speed of 40 meters per second. That is my speed
relative to point A.

Now you describe my speed relative to the speed of light.

-- Jeff, in Minneapolis

In my deep space example, for a lone spacecraft, there is no "point A" and so the only reference the commander can use is with respect to the speed of light.

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

Michelson-Morley

Looking at the M-M setup (http://en.wikipedia.org/wiki/Image:Michelson-morley.png) it can be noted that there are two one-way segments in the path: one vertical through the glass and one horizontal through the glass. This could be the cause of the small effect measured. I thought about using fiber optics to route the light and produce a one-way measurement but never thought it through all the way.

Jeff Root
2006-Oct-11, 03:58 PM
I can measure my speed relative to point A by measuring the
distance from me to point A at one instant, then measuring
the distance again at another instant, subtracting to get the
difference, and dividing by the time interval. For example, the
first distance might be 10 meters, and the second distance
might be 50 meters, and the time interval might be 1 second.
That gives a speed of 40 meters per second. That is my speed
relative to point A.

Now you describe my speed relative to the speed of light.
In my deep space example, for a lone spacecraft, there is no
"point A" and so the only reference the commander can use is
with respect to the speed of light.
Okay, so go ahead and describe my speed relative to the
speed of light, as I described my speed relative to point A.

-- Jeff, in Minneapolis

Squashed
2006-Oct-11, 05:21 PM
Okay, so go ahead and describe my speed relative to the
speed of light, as I described my speed relative to point A.

-- Jeff, in Minneapolis

Jeff, I do not know where you are headed with your line of questions. If you are leading into an analogy similar to SeanF's football analogy then perhaps you should just state what you want to say. It seems like you might want to determine an absolute coordinant system but I have no idea if what I have been pointing out will lead to that conclusion or not. The more I think about it the more I think an absolute origin is required but it is all speculation so far to me. I merely realized that if the light must travel different distances between the mirrors then that necessity will have results that can be detected.

SeanF
2006-Oct-11, 06:09 PM
Looking at the simple diagram (http://en.wikipedia.org/wiki/Image:Michelson-morley.png) they give it is easy to see that the light makes complete round trips and so no interference should be expected.
The "red" light coming down from the mirror to the detector is a combination of the "blue" light coming from the top (through the mirror) and the "green" light coming from the right (reflected off the mirror). That downard "red" light will have an interference pattern unless the blue round trip is the exact same length as the green round trip.

Squashed
2006-Oct-11, 06:25 PM
The "red" light coming down from the mirror to the detector is a combination of the "blue" light coming from the top (through the mirror) and the "green" light coming from the right (reflected off the mirror). That downard "red" light will have an interference pattern unless the blue round trip is the exact same length as the green round trip.

The only one-way lengths for both light beams is the length that they both have in common: down to the detector and so the effect of that one-way length is the same for both light beams.

They show the blue and green light forming triangles which is probably just a visualization thing but even if those are true paths an analysis will reveal that each one-way X & Y portion is matched by a return path along the X & Y.

My comment about the one-way portion through the glass is significant because the light goes "slower" in the glass medium and so that light beam spends a little bit longer traveling along that segment than the other light beam does since the other beam goes through a vacuum. So one beam spends a little more time traveling along the vertical whilst the other beam spends a little more time traveling along the horizontal which may, hypothetically, have caused the small amount of interference that was detected.

SeanF
2006-Oct-11, 07:06 PM
The only one-way lengths for both light beams is the length that they both have in common: down to the detector and so the effect of that one-way length is the same for both light beams.

They show the blue and green light forming triangles which is probably just a visualization thing but even if those are true paths an analysis will reveal that each one-way X & Y portion is matched by a return path along the X & Y.
The triangle is most definitely a visualization thing.

X is matched by X', and Y is matched by Y' (X being blue, Y being green, non-prime being one way, and prime the other way).

But if X+X' does not equal Y+Y', there will be interference.


My comment about the one-way portion through the glass is significant because the light goes "slower" in the glass medium and so that light beam spends a little bit longer traveling along that segment than the other light beam does since the other beam goes through a vacuum. So one beam spends a little more time traveling along the vertical whilst the other beam spends a little more time traveling along the horizontal which may, hypothetically, have caused the small amount of interference that was detected.
Both light beams, by the time they reach the detector, will have reflected off the semi-silvered mirror once and traveled straight through it once, so that shouldn't cause any significant interference.

Squashed
2006-Oct-11, 07:26 PM
...

But if X+X' does not equal Y+Y', there will be interference.

...

Switching perspectives back to a stationary observer:

If the M-M experiment were performed inside the spacecraft going at 0.8c then even though the length along the X-axis is length contracted the round-trip time for the shortened X distance and the longer perpendicular Y distance will be the same: no interference.

The round-trip ellapsed times are the same (0.6 second) whether the clock is aligned to the X-axis or perpendicular to the X-axis (or both as in the M-M experiment).

SeanF
2006-Oct-11, 07:39 PM
Switching perspectives back to a stationary observer:

If the M-M experiment were performed inside the spacecraft going at 0.8c then even though the length along the X-axis is length contracted the round-trip time for the shortened X distance and the longer perpendicular Y distance will be the same: no interference.

The round-trip ellapsed times are the same (0.6 second) whether the clock is aligned to the X-axis or perpendicular to the X-axis (or both as in the M-M experiment).
I'm thinking I shouldn't have brought M-M into this discussion at this point, as I don't think it's really relevant to what we were discussing. :shifty:

But let's look at that diagram (http://en.wikipedia.org/wiki/Image:Michelson-morley.png) for a moment.

The triangle in the blue lines is, as we said, a visualization aid. Those two lines would actually be parallel to each other (in fact, they would effectively be the same line) - but only if the apparatus is motionless.

If the entire apparatus were moving parallel to the green lines, the blue lines would have to be angled in order to get from the silvered mirror to the top mirror and back to the silvered mirror.

Agreed?

Squashed
2006-Oct-11, 07:45 PM
Agreed?

I agree and I should point out that the green lines would be length contracted and so the two effects would cancel and the amount of time taken to complete both round trips would be the same.

In the M-M experiment we basically have two separate light-reflection clocks that tick once each: one clock (green) is aligned to the direction of motion and the other (blue) is perpendicular to the direction of motion (if the direction of motion is parallel to the green horizontal line).

I should add that the original M-M experiment (1887) was designed before the theory of relativity (1905) and so they had no reason to believe that the amount of time back and forth between the silvered mirror and the reflecting mirrors would be equivalent in every conceivable circumstance.

SeanF
2006-Oct-11, 08:33 PM
I agree...
All right. The angle between the blue and green rays is 90 degrees when the apparatus is not moving, but less than (or more than) 90 degrees when the apparatus is moving. This is why both rays hit the same spots on the apparatus (the two mirrors). So, we can't detect motion along the green axis by looking to see whether the blue ray hits its mirror - it will, regardless.

Now, back to your idea of using a spotlight to detect motion based on the size of the circle. The only reason the circle is a different size at different distances is because the light rays are not parallel - the rays that make the edge of the circle are travelling at an angle from the rays in the center of the circle. Just like with the blue and green rays on the M-M apparatus, though, that angle is not preserved when we switch from one reference frame to another.

Because of that, the circle the spotlight makes on the wall will be the same size regardless of whether the room is moving or not. So, we cannot detect motion by looking at where the edge of the circle is on the wall - it'll be in the same place either way.

Jeff Root
2006-Oct-11, 09:08 PM
Okay, so go ahead and describe my speed relative to the
speed of light, as I described my speed relative to point A.
Jeff, I do not know where you are headed with your line of
questions.
I am trying to understand what you mean by the expression,
"our speed relative to the speed of light". The only way I
can understand what you mean by it is for you to explain or
describe it. So I'm trying to get you to explain or describe
it, like I described my speed relative to point A.



If you are leading into an analogy similar to SeanF's football
analogy then perhaps you should just state what you want to say.
No analogy. I'm trying to find out what you mean by the
expression, "our speed relative to the speed of light".

-- Jeff, in Minneapolis

trinitree88
2006-Oct-11, 09:29 PM
Squashed,

Please try again. I'm going to add a step:

First, explain what is meant by "the speed of light".
That should be easy, since your explanation should be
equivalent to that of anyone else.

Then explain what you mean by the expression,
"our speed relative to the speed of light". That may
be more difficult, since it is unique to you.

-- Jeff, in Minneapolis

Thanks Jeff..been a long week..:dance: :shifty: :clap: :eek: ;) Pete

Squashed
2006-Oct-12, 12:09 PM
I am trying to understand what you mean by the expression,
"our speed relative to the speed of light". The only way I
can understand what you mean by it is for you to explain or
describe it. So I'm trying to get you to explain or describe
it, like I described my speed relative to point A.


No analogy. I'm trying to find out what you mean by the
expression, "our speed relative to the speed of light".

-- Jeff, in Minneapolis

I understand what you are asking (I'm a little "slow" sometimes). I can honestly say I am not real sure myself since I just recently came to this realization - which is why I asked the original question, but here goes ...

In the calculations (http://www.bautforum.com/showpost.php?p=839544&postcount=25) that SeanF did to show me that a light-reflection clock aligned parallel to the direction of movement will still function just as reliably as a clock aligned perpendicular to the direction of movement (as long as a round-trip value is used) he used the speed of light (from the stationary reference frame but the speed of light is the same for all frames). The calculations require the light to travel different lengths in order for the calculations to figure the same time for both the parallel and perpendicular clocks - it is this speed of light that is being referenced.

If the spreading of light according to the inverse square relation works then it will give a proportion that can be used to calculate the ship speed as a fraction of the speed of light - this is a scalar quantity which means it has no direction to it (but I'm not sure if this scalar-ness can be true).

So looking at the light in the stationary frame the observer would see the light spreading according to the inverse square relation and the stationary observer must see two different size spots on the forward wall and the backward wall of the spaceship.

Length contraction only occurs in the direction of travel and so the spots should retain their size (since it is a perpendicular measurement) for the traveler as well - this is all because of the one-way characteristic of light to spread out as it travels.

Squashed
2006-Oct-12, 12:21 PM
All right. The angle between the blue and green rays is 90 degrees when the apparatus is not moving, but less than (or more than) 90 degrees when the apparatus is moving. This is why both rays hit the same spots on the apparatus (the two mirrors). So, we can't detect motion along the green axis by looking to see whether the blue ray hits its mirror - it will, regardless. ...

The two "clock" portions (green & blue) of the M-M arrangement (http://en.wikipedia.org/wiki/Image:Michelson-morley.png) will keep an accurate time no matter what their orientation because the round-trip makes it a perfect clock. All the one-way segments that remain in the apparatus are exactly matched for both rays of light - so the M-M experiment was "designed to fail" to measure the property that it was hoped to be measured.

In the Wikipedia article (http://en.wikipedia.org/wiki/Michelson-Morley_experiment) it states that the idea came from the speed of sound in air and the article noted that if there is a 10 m/s wind then the speed of sound would be 350 m/s with the wind and 330 m/s against the wind which when averaged equals 340 m/s which is the speed of sound in still air. The round-trip speed of sound will always give an accurate speed of sound in still air and the same is true for the speed of light.

The real question about the M-M experiment is: Why are we still running the test when for 101 years (since 1905) we have known that the round-trip speed of light will always equal the speed of light in a stationary frame?

Jeff Root
2006-Oct-12, 01:39 PM
I'm trying to find out what you mean by the expression,
"our speed relative to the speed of light".
I understand what you are asking (I'm a little "slow" sometimes).
I can honestly say I am not real sure myself since I just
recently came to this realization - which is why I asked the
original question, but here goes ...

In the calculations that SeanF did to show me that a light-
reflection clock aligned parallel to the direction of movement
will still function just as reliably as a clock aligned
perpendicular to the direction of movement (as long as a
round-trip value is used) he used the speed of light (from the
stationary reference frame but the speed of light is the same
for all frames). The calculations require the light to travel
different lengths in order for the calculations to figure the
same time for both the parallel and perpendicular clocks - it
is this speed of light that is being referenced.
That tells us nothing.



If the spreading of light according to the inverse square
relation works
It doesn't.



then it will give a proportion that can be used to calculate
the ship speed as a fraction of the speed of light - this is
a scalar quantity which means it has no direction to it
(but I'm not sure if this scalar-ness can be true).

So looking at the light in the stationary frame the observer
would see the light spreading according to the inverse square
relation and the stationary observer must see two different size
spots on the forward wall and the backward wall of the spaceship.

Length contraction only occurs in the direction of travel and so
the spots should retain their size (since it is a perpendicular
measurement) for the traveler as well - this is all because of
the one-way characteristic of light to spread out as it travels.
Sorry. It doesn't work.

-- Jeff, in Minneapolis

SeanF
2006-Oct-12, 02:17 PM
If the spreading of light according to the inverse square relation works then it will give a proportion that can be used to calculate the ship speed as a fraction of the speed of light - this is a scalar quantity which means it has no direction to it (but I'm not sure if this scalar-ness can be true).
Light doesn't spread according to the inverse square law - not the way you're talking about. All the inverse square law says is that a given area will receive a quarter of the light at twice the distance if the light source is emitting its light equally in all directions.

A one-inch wide laser beam - perfectly parallel light rays - will project a one-inch wide spot on a wall no matter how far away the wall is.

A standard flashlight or spotlight will make a bigger spot the farther away the wall is, but that's because of the non-parallel angles of the light rays leaving the emitter. Those angles are not preserved when switching reference frames.

Jeff Root
2006-Oct-12, 02:42 PM
Sean,

Laser beams aren't ever perfectly parallel, of course, and optical
theory predicts how much the beam will diverge at a minimum.

All that is largely irrelevant to Squashed's idea.

-- Jeff, in Minneapolis

LayMan
2006-Oct-12, 03:28 PM
I know I'm probably the last guy to get mixed up in this, but here's my 2 cents...

If there is only an external light source (like a far away galaxy or quasar), then you can use the hubble effect, but that will only produce a relative speed. If there is only an internal light source, then that light source will be traveling at the same speed as the spaceship and it's walls, so the speed of light will always be the same. If we were sitting in a train and tossing a ball towards each other, neither one of us would have to throw harder then the other, since the ball is travelling along at the same speed as we are, and so is the air in the compartment. Things would of course be different if the compartment had an open roof, causing draft, but I don't think that applies to light, since photons are massless, no? I think the only way the idea is going to work, is when the space ship is nearing a black hole causing the distance between front wall - light source to increase more rapidly then the distance light source - back wall... But still that would only give you an absolute value of the extorsion of the ship, not its absolute speed as a whole... I think...

SeanF
2006-Oct-12, 04:03 PM
Sean,

Laser beams aren't ever perfectly parallel, of course, and optical
theory predicts how much the beam will diverge at a minimum.

All that is largely irrelevant to Squashed's idea.

-- Jeff, in Minneapolis
Yeah, I thought about putting that in a footnote, but I was afraid it would distract from my point.

Thanks a lot.

;)

Squashed
2006-Oct-12, 04:12 PM
Light doesn't spread according to the inverse square law - not the way you're talking about. All the inverse square law says is that a given area will receive a quarter of the light at twice the distance if the light source is emitting its light equally in all directions.
...

If the angle of the beam remains constant (thinking in a single reference frame) then the size of the spot doubles if the distance between the source (spotlight) and receiver (wall) doubles which means the area covered by the spot increases by the square of the distance and so if the distance doubles then the area covered is 22=4 times the original distance. The photon density (which is what I meant) decreases by the inverse square of the distance.

Squashed
2006-Oct-12, 04:17 PM
...If there is only an internal light source, then that light source will be traveling at the same speed as the spaceship and it's walls, so the speed of light will always be the same. ...

The way I read this it sounds like you are advocating a variable speed of light and so the speed of light towards the direction of travel would be: c+v

and the speed of light away from the direction of travel would be: c-v

Squashed
2006-Oct-12, 04:29 PM
...
Those angles are not preserved when switching reference frames.

In order for the light to create the same size spot on both walls with the spotlight positioned in the center between the front and back walls then the angle of the spreading light would have to be different for each direction: a wider angle towards the positive X-axis and a narrower angle towards the negative X-axis (the ship is traveling in the positive direction along the X-axis). The light travels different distances depending upon whether it is pointed towards the positive X-axis or negative X-axis.

SeanF
2006-Oct-12, 04:49 PM
Light doesn't spread according to the inverse square law - not the way you're talking about. All the inverse square law says is that a given area will receive a quarter of the light at twice the distance if the light source is emitting its light equally in all directions.
...
If the angle of the beam remains constant (thinking in a single reference frame) then the size of the spot doubles if the distance between the source (spotlight) and receiver (wall) doubles...
Assuming a point-source, sure. Absolutely correct.



...
Those angles are not preserved when switching reference frames.
In order for the light to create the same size spot on both walls with the spotlight positioned in the center between the front and back walls then the angle of the spreading light would have to be different for each direction...
Yes. And it is. That's Relativity.

Jeff Root
2006-Oct-12, 05:35 PM
But still that would only give you an absolute value of the
extorsion of the ship, not its absolute speed as a whole...
Hmmmm. Cute word. In or near a black hole, one is subjected
to dilation, spaghettification, and extorsion.

-- Jeff, in Minneapolis

Squashed
2006-Oct-12, 05:53 PM
...

Yes. And it is. That's Relativity.

Then doesn't that imply that length contraction occurs perpendicular to the direction of motion rather than parallel to the direction of motion?

Think of a cone made out of steel aligned on the X-axis, then depending upon whether it is pointed down the positive X-axis or the negative X-axis a stationary observer would see two different cones: a variable length contraction perpendicular to the motion but a consistent length contraction parallel to the motion.

swansont
2006-Oct-12, 06:18 PM
If the angle of the beam remains constant (thinking in a single reference frame) then the size of the spot doubles if the distance between the source (spotlight) and receiver (wall) doubles which means the area covered by the spot increases by the square of the distance and so if the distance doubles then the area covered is 22=4 times the original distance. The photon density (which is what I meant) decreases by the inverse square of the distance.


But the angle doesn't remain constant for a laser. The near-field and far-field divergences are different. It approaches the constant angle behavior in the limit of large distances.

SeanF
2006-Oct-12, 07:23 PM
Then doesn't that imply that length contraction occurs perpendicular to the direction of motion rather than parallel to the direction of motion?

Think of a cone made out of steel aligned on the X-axis, then depending upon whether it is pointed down the positive X-axis or the negative X-axis a stationary observer would see two different cones: a variable length contraction perpendicular to the motion but a consistent length contraction parallel to the motion.
No. The stationary observer would see the same cone no matter which way it is pointed.

However, a photon traveling along the edge of the cone from the tip to the base would trace a different path through space if the cone is moving point-first than if it is moving base-first. I'm not sure how to explain this, though, without some kind of animation...

Such an animation would show the simultaneity discrepancy part of Relativity, too...maybe I should try and come up with one.

Squashed
2006-Oct-12, 07:48 PM
Using this arrangement (http://www.bautforum.com/attachment.php?attachmentid=3724&stc=1&d=1160682340) an experiment to test the possibility can easily be created.

The beam is split by the mirrors to divert each half to a wall and I would suggest that the spotlight be rotated about the Y-axis so that the filament shape will not cause a disparity.

The test could be run on the earth and/or in a moving evironment (space station).

Run the test for several different lengths of time to determine if any trend in photon count is real or just experiment error.

This would be a real test for both relativity and for the existence of an ether.

Kristophe
2006-Oct-12, 08:53 PM
Using this arrangement (http://www.bautforum.com/attachment.php?attachmentid=3724&stc=1&d=1160682340) an experiment to test the possibility can easily be created.

The beam is split by the mirrors to divert each half to a wall and I would suggest that the spotlight be rotated about the Y-axis so that the filament shape will not cause a disparity.

The test could be run on the earth and/or in a moving evironment (space station).

Run the test for several different lengths of time to determine if any trend in photon count is real or just experiment error.

This would be a real test for both relativity and for the existence of an ether.

Just a quick question from a silent-until-now casual reader: How does this suggested experiment work? What result does ether theory predict? What result does relativity theory predict? If someone were to run this test, what should they be looking for?

Squashed
2006-Oct-13, 11:23 AM
Just a quick question from a silent-until-now casual reader: How does this suggested experiment work? What result does ether theory predict? What result does relativity theory predict? If someone were to run this test, what should they be looking for?

How does the experiment work? Since the relativistic calculations require the light to travel different distances for each one-way leg then those different distances have consequences that would be evident through the one-way characteristic of light that causes it to spread out. When the light spreads out its intensity changes which is what the photon detectors would measure. The more spread out the light the fewer photons there will be striking the photon detector. So one side of the proposed experiment should receive more photon hits than the other side.

I expect that the two photon detectors should register different quantities of photon hits because I feel that this is called for in the relativistic calculations.

If the test comes back positive, meaning there is a difference in the number of photons striking both detectors, then it is debate-able as to whether the result is caused by an ether or the constant speed of light. I do not know how to distinguish between the two.

Squashed
2006-Oct-13, 11:55 AM
Using this arrangement (http://www.bautforum.com/attachment.php?attachmentid=3724&stc=1&d=1160682340) an experiment to test the possibility can easily be created.

...

When light travels a round-trip it is not only a perfect clocking mechanism but it also a perfect meterstick. This meterstick can be used to precisely locate the components of the test to ensure that the distance between the two walls is exactly halved by the beam-splitting mirrors. Using a Michelson-Morley setup the interference pattern can be monitored to determine whether the experimental components remain positioned correctly.

The space station/shuttle is not needed to perform this test because we can always use the earth's rotational velocity much more cheaply than launching the experiment into space (although it would be good if a space-based experiment were performed).

On earth the two photon detectors can be calibrated or have their individual characteristics mapped by having the whole experimental apparatus rotateable. When the assembly is rotated so that one detector is towards the north and one is towards the south (perpendicular to the earth's rotational velocity) then the relativistic calculations dictate that the two photon detectors will receive an equal number of photon hits. For added accuracy the assembly should be rotated 180 degrees so that the formerly north detector is towards the south and the formerly south detector is towards the north. Once the reliability of the detectors and the setup are determined then the whole assembly can be rotated so that one detector is towards the east and one detector is towards the west - this should allow the assembly to detect the rotational velocity of the earth.

If the test comes back positive for the earth rotational velocity then long term monitoring over years could be employed and computers could be used to filter the data to eliminate the rotation of the earth; the earth's motion around the sun; and the sun's movement in our galaxy.

SeanF
2006-Oct-13, 01:50 PM
Since the relativistic calculations require the light to travel different distances for each one-way leg then those different distances have consequences that would be evident through the one-way characteristic of light that causes it to spread out.
You're misunderstanding Relativity.

It's normal old Newtonian physics which say that the light would travel different distances for each one-way leg. What Relativity says is that there will be time dilation, length contraction, and simultaneity differences which will all combine to the final effect that we cannot tell the difference.

If you were to put identical apparatus on two ships, and have one "stationary" and the other "moving" at 0.6c, Relativity says that there would be no difference in the results of the experiments on the two ships. A situation with Ship A moving and Ship B stationary would produce the exact same results on both ships as a situation with Ship B moving and Ship A stationary. That is what the "relativistic calculations" predict.

Jeff Root
2006-Oct-13, 02:41 PM
This thread belongs in Against the Mainstream.

-- Jeff, in Minneapolis

Squashed
2006-Oct-13, 02:43 PM
You're misunderstanding Relativity.

It's normal old Newtonian physics which say that the light would travel different distances for each one-way leg. What Relativity says is that there will be time dilation, length contraction, and simultaneity differences which will all combine to the final effect that we cannot tell the difference.

If you were to put identical apparatus on two ships, and have one "stationary" and the other "moving" at 0.6c, Relativity says that there would be no difference in the results of the experiments on the two ships. A situation with Ship A moving and Ship B stationary would produce the exact same results on both ships as a situation with Ship B moving and Ship A stationary. That is what the "relativistic calculations" predict.

I understand your post and I agree, to an extent, because that is the way I always thought relativity would work but I have no problem with running the test because we still run the M-M test even though someone should have realized within the last 100 years that it is designed to test nothing in regards to the ether - as I have pointed out.

One benefit of the M-M experiment is the verification that the round-trip speed of light is an accurate time-keeping mechanism in every circumstance and orientation. Something good will probably come from my proposed test even if it does return a null result.

We spend money and time continuing to run the M-M test ... why not my proposed test instead or also?

Squashed
2006-Oct-13, 04:50 PM
This thread belongs in Against the Mainstream.

-- Jeff, in Minneapolis

Why Jeff I would think you would be interested in my proposition even if only to actually verify the non-existence of the ether. As it is, the Michelson-Morley ill-designed experiment still leaves open the possibility for an ether.

In several discussions I have had at this site it was proclaimed that the M-M experiment abolished the notion of an ether but since the M-M experiment does no such thing then such a claim is reduced to mere opinion and/or bias.

The fact that mainstream science still runs the Michelson-Morley apparatus indicates a need for an assurance of the non-existence of the ether and this action renders this discussion a true mainstream topic.

SeanF
2006-Oct-13, 04:54 PM
We spend money and time continuing to run the M-M test ... why not my proposed test instead or also?
Earth's orbital velocity around the sun is about 30kps. The speed of light is about 300,000kps. That means Earth's velocity is about .0001c.

What degree of difference would you expect to find in the two directions in your experiment? Would it even be measurable by our technology?

Squashed
2006-Oct-13, 05:36 PM
Earth's orbital velocity around the sun is about 30kps. The speed of light is about 300,000kps. That means Earth's velocity is about .0001c.

What degree of difference would you expect to find in the two directions in your experiment?

This would have to be calculated, of course, in order to determine the parameters of the actual experiment. One advantage of my proposed setup is the ability to accumulate results over time rather than rely on a single pulse of light.


Would it even be measurable by our technology?

The fact that a quantity is difficult to measure should not stop determined minds from endeavoring to do such.

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

Here is another idea that could be employed:

Using two identical and synchonized atomic clocks each paired with a laser move them apart and at a predetermined time each would fire a laser, or light beam, in the direction of the other towards a pair of merging mirrors - if an interference pattern is produced by the merged beams then that would be a positive indicator.

I can not say for sure if this setup would satisfy the simultaneity problems of separate clocks but it sounds feasible.

AMDG
2006-Oct-13, 05:57 PM
Since the speed of light is the absolute fastest speed then doesn't that define an absolute reference frame since all velocities must fall between zero and the speed of light?

If we could determine our speed relative to the speed of light then would that prove that there is an absolute reference frame? (I personally do not believe in an "ether" or geocentrism - so don't think I am advocating either of these ideas.)

The "perfect" clocking device is the light-reflection clock of thought experiment fame but it seems that it is only accurate as long as time is measured by the round-trip path of light. By round-trip I mean the light must start at one mirror then travel a one-way segment to reflect off the other opposing mirror for a second one-way segment which returns the light to the first mirror again (a round-trip between the mirrors).

I have been pondering trying to use a setup of mirrors so that I can compare the two one-way times that compose the round-trip but have had no luck so far because every ingenious idea I have ends up being composed of just multiple round trips.

Thanks for any input in regard to the above - I am still working on some ideas but will not be able to post for a couple days.
You are looking for OWLS exps - One Way Light Signal

We can give you some links , but be warned they show luminal anisotropy, like the TWLS Sagnac effect ...
they may violate the MS rules.... :naughty:

Wisp Unification Theory - almost the theory of everything (http://uk.geocities.com/kevinharkess/oneway/oneway.html)

OWLS Comparison Experiment (\\www.users.bigpond.com\hewn\moonrelay.jpg)

Light clock experiment clarified (http://www.usenet.com/newsgroups/sci.physics/msg12146.html)

Jeff Root
2006-Oct-13, 06:13 PM
Why Jeff I would think you would be interested in my proposition
even if only to actually verify the non-existence of the ether.
As it is, the Michelson-Morley ill-designed experiment still
leaves open the possibility for an ether.
Sorry, Squashed, but you have no real understanding of the
Michelson-Morely experiment or of special relativity. Your
geometric analysis is wrong because it is based on your
confused notions of physics.

I asked you five or six times to explain what you meant by
"our speed relative to the speed of light", but although you
replied each time, you never answered the question. You
evidently do not know what you meant.



In several discussions I have had at this site it was proclaimed
that the M-M experiment abolished the notion of an ether but
since the M-M experiment does no such thing then such a claim is
reduced to mere opinion and/or bias.
You say that with a seriously flawed understanding of how the
MMX works and without trying to correct your errors. You can
imagine what I think.



The fact that mainstream science still runs the Michelson-Morley
apparatus indicates a need for an assurance of the non-existence
of the ether and this action renders this discussion a true
mainstream topic.
You've demonstrated that you don't understand the MMX, and that
you aren't interested in understanding it.

I understand why your geometric analysis is wrong. I can't
explain it to you because you aren't interested in learning.
You are only interested in showing that mainstream physics
is wrong.

-- Jeff, in Minneapolis

Squashed
2006-Oct-13, 06:52 PM
Sorry, Squashed, but you have no real understanding of the
Michelson-Morely experiment or of special relativity. Your
geometric analysis is wrong because it is based on your
confused notions of physics.

I asked you five or six times to explain what you meant by
"our speed relative to the speed of light", but although you
replied each time, you never answered the question. You
evidently do not know what you meant.


You say that with a seriously flawed understanding of how the
MMX works and without trying to correct your errors. You can
imagine what I think.


You've demonstrated that you don't understand the MMX, and that
you aren't interested in understanding it.

I understand why your geometric analysis is wrong. I can't
explain it to you because you aren't interested in learning.
You are only interested in showing that mainstream physics
is wrong.

-- Jeff, in Minneapolis

Thanks for the reply. I would greatly appreciate you're explaining the problems with my geometric analysis, especially for the MMX because it seems like a simple enough concept.

I read SeanF's explanation of angle variation in regard to relativistic situations but I do not recall you offering any explanations.

You seem to think I am only interested in disproving mainstream physics but that is not true because I want to advance our understanding of the universe. I look at Newton and Einstein and others' contributions to science and I see stepping stones towards greater understanding and knowledge but I do not see us at the pinacle yet and so this must mean we do not know everything and therefore I look for different avenues to explore. Quantum physics and relativity seem incompatible and so either one of the two must change or a third theory must unite them - without exploring questions I can see no progress ever happening.

I am sorry you feel that way about my efforts on this site, I will try to live with your disdain and hopefully you can learn to live with my skepticism.

SeanF
2006-Oct-13, 07:27 PM
The fact that a quantity is difficult to measure should not stop determined minds from endeavoring to do such.
Of course it should. If it can be determined that the quantity would be too small to be measured, the experiment would be worthless. Utterly.

That's why I asked you to determine the quantity - it's your experiment, after all, and you won't convince anyone to do it unless you can convince them it won't be worthless.


Thanks for the reply. I would greatly appreciate you're explaining the problems with my geometric analysis, especially for the MMX because it seems like a simple enough concept.
I suggest you start, as he asked, by defining "the speed of light" and "our speed relative to the speed of light."

Jeff Root
2006-Oct-13, 09:54 PM
Thanks for the reply. I would greatly appreciate you're
explaining the problems with my geometric analysis, especially
for the MMX because it seems like a simple enough concept.
As Sean said, the first steps in understanding what is wrong
with your analysis are to understand what is meant by "the
speed of light" and what you mean by "our speed relative to
the speed of light". I find that an excellent way to learn
about a thing is to explain it to someone else. So I've asked
you repeatedly to explain those two phrases to me. Until you
do that, I can't help you.

An explanation of "the speed of light" should include an
explanation of what "speed" is in general, and should then
go on to explain how that concept can be applied to light.

An explanation of "our speed relative to the speed of light"
needs to be even more explicit and detailed, since it is your
original idea and you are the only person who can explain
what it means. I think it would be a good idea to include
at least three numerical examples, like the example I gave
of my speed relative to the imaginary "point A". Your
examples should illustrate how "our speed" is related to
"the speed of light".

It would also be good for you to explain the MMX in some detail.
The Sagnac experiment, although more complex, might be helpful
for you to explain, too, because it produces a non-null result.



I read SeanF's explanation of angle variation in regard to
relativistic situations but I do not recall you offering any
explanations.
Since you were not absorbing Sean's comments, I tried to prompt
you to do the explaining.

-- Jeff, in Minneapolis

swansont
2006-Oct-15, 10:52 PM
Using two identical and synchonized atomic clocks each paired with a laser move them apart and at a predetermined time each would fire a laser, or light beam, in the direction of the other towards a pair of merging mirrors - if an interference pattern is produced by the merged beams then that would be a positive indicator.



How would you synchronize the clocks, and keep them synchronized?

Nereid
2006-Oct-16, 12:12 AM
After three pages and >60 posts, it seems this thread is rapidly becoming an ATM one (especially with the introduction of acknowledged ATM material, by AMDG).

Squashed, if you are really interested in understanding relativity, then please, at the very least, try to define the key aspects of the Gedankenexperiment you have (vaguely) sketched. Several folk have asked you about this, but, as far as I can see, you have been unable, or unwilling, to supply the necessary clarifications.

There are many counter-intuitive aspects to relativity, and being very precise about your definitions and concepts is one way to start to come to grips with these counter-intuitives.

Squashed
2006-Oct-16, 02:42 PM
After three pages and >60 posts, it seems this thread is rapidly becoming an ATM one (especially with the introduction of acknowledged ATM material, by AMDG).

Squashed, if you are really interested in understanding relativity, then please, at the very least, try to define the key aspects of the Gedankenexperiment you have (vaguely) sketched. Several folk have asked you about this, but, as far as I can see, you have been unable, or unwilling, to supply the necessary clarifications.

There are many counter-intuitive aspects to relativity, and being very precise about your definitions and concepts is one way to start to come to grips with these counter-intuitives.

I am sorry if I have not communicated my idea clearly. Not being a relativity expert I do not have a good handle on the lingo used and the precise meaning of words used in context to these types of discussions. I feel I am being clear but in ten years (I hope it does not take so long) I may look back at these posts and laugh at the ambiguity of my statements.

As far as AMDG's post I have no control over what other people post in my threads, I can only try to answer questions that pertain to the topic. One might think we strayed off topic in discussing the MMX but I feel it did have relavance to the idea I presented.

I will try to explain better and answer Jeff Root's question but it may take a while.

Thanks for your input.

Squashed
2006-Oct-18, 01:24 PM
As Sean said, the first steps in understanding what is wrong
with your analysis are to understand what is meant by "the
speed of light" and what you mean by "our speed relative to
the speed of light". I find that an excellent way to learn
about a thing is to explain it to someone else. So I've asked
you repeatedly to explain those two phrases to me. Until you
do that, I can't help you.

An explanation of "the speed of light" should include an
explanation of what "speed" is in general, and should then
go on to explain how that concept can be applied to light.

An explanation of "our speed relative to the speed of light"
needs to be even more explicit and detailed, since it is your
original idea and you are the only person who can explain
what it means. I think it would be a good idea to include
at least three numerical examples, like the example I gave
of my speed relative to the imaginary "point A". Your
examples should illustrate how "our speed" is related to
"the speed of light".

It would also be good for you to explain the MMX in some detail.
The Sagnac experiment, although more complex, might be helpful
for you to explain, too, because it produces a non-null result.


Since you were not absorbing Sean's comments, I tried to prompt
you to do the explaining.

-- Jeff, in Minneapolis

Okay, I have not had much free time lately but I have been reading about the MMX (http://galileoandeinstein.physics.virginia.edu/lectures/michelson.html) and I note in the description that I am reading that it states that:

"It is now possible to produce particles, called neutral pions, which decay each one in a little explosion, emitting a flash of light. It is also possible to have these pions moving forward at 185,000 miles per second when they self destruct, and to catch the light emitted in the forward direction, and clock its speed. It is found that, despite the expected boost from being emitted by a very fast source, the light from the little explosions is going forward at the usual speed of 186,300 miles per second."

Now according to the neutral pion the speed of light compared to the pion's speed would be 186,300 - 185,000 = 1,300 miles per second so it does not matter what is the speed of the emitter or receiver, the speed of light always ends up to being 186,300 miles per second ... this is all as measured from a single reference frame.

So, if I were to believe in an ether, then the ether would have to be stationary and all objects move or reside within this stationary ether. Let me state that I do not believe in an ether but somehow light always ends up traveling at this constant speed no matter how fast the emitter or receiver.

There are two simultaneous velocities in the above: that of light and that of the pion; which over any ellapsed time results in a distance traveled so the light will increase its distance between the pion and itself and this distancing is a relative velocity that is the result of the two velocities.

The above does not answer all your questions and I am sorry for that but like I said it will take some time which I do not have much of.

After re-reading what I just wrote I think the thrust of my proposition is in determining the 1,300 miles per second value within the frame of the pion ... if that helps any with your understanding.

Jeff Root
2006-Oct-18, 05:13 PM
Now according to the neutral pion the speed of light compared to
the pion's speed would be 186,300 - 185,000 = 1,300 miles per second
so it does not matter what is the speed of the emitter or receiver,
the speed of light always ends up to being 186,300 miles per second
... this is all as measured from a single reference frame.
Are you saying it is all from the pion's reference frame?



So, if I were to believe in an ether, then the ether would have
to be stationary and all objects move or reside within this
stationary ether. Let me state that I do not believe in an ether
but somehow light always ends up traveling at this constant speed
no matter how fast the emitter or receiver.

There are two simultaneous velocities in the above: that of light
and that of the pion; which over any ellapsed time results in a
distance traveled so the light will increase its distance between
the pion and itself and this distancing is a relative velocity
that is the result of the two velocities.
The pion moves through the air at 185,000 miles per second.
The pion sees the light moving away from it at 186,300 miles
per second. We see the light moving away from the pion at
1,300 miles per second relative to the pion.



The above does not answer all your questions and I am sorry for
that but like I said it will take some time which I do not have
much of.

After re-reading what I just wrote I think the thrust of my
proposition is in determining the 1,300 miles per second value
within the frame of the pion ... if that helps any with your
understanding.
The pion sees its speed through the air as 185,000 miles per
second, just as an observer at rest relative to the air does.
So the pion sees its speed through the air as 1,300 miles per
second less than the speed of light, just as an observer at
rest relative to the air does. But the pion sees light move
away from itself at 186,300 miles per second, as always. The
pion also sees the atmosphere and Earth as compressed in the
direction of its motion, and sees clocks which are at rest
relative to the atmosphere and Earth as slowed (with a major
adjustment for Doppler redshift/blueshift).

-- Jeff, in Minneapolis