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earthman2110
2004-Jan-23, 10:23 PM
All electromagnetic waves travel at the same speed through a vacuum, a value somthing around 300,000 km / s. Einstein says in his theory of relativity that the speed of light is always the same, no matter how fast its source is traveling. Speed of an electromag. wave is just freq. times wavelength. Given this, how is Red Shift possible? Even if the source of light is traveling away from us, the light is still traveling at a constant speed. Does the freq. change as well? Thank you

daver
2004-Jan-23, 10:44 PM
All electromagnetic waves travel at the same speed through a vacuum, a value somthing around 300,000 km / s. Einstein says in his theory of relativity that the speed of light is always the same, no matter how fast its source is traveling. Speed of an electromag. wave is just freq. times wavelength. Given this, how is Red Shift possible? Even if the source of light is traveling away from us, the light is still traveling at a constant speed. Does the freq. change as well? Thank you

Yes, the frequency changes as well.

earthman2110
2004-Jan-23, 10:54 PM
But what causes the freq. to change and why does it only happen over such a huge distance?

George
2004-Jan-23, 11:30 PM
But what causes the freq. to change and why does it only happen over such a huge distance?

Surprisingly, "space" is expanding (Big Bang Theory) and the light gets stretched. This increases the wavelength and, therefore, lowers the frequency (red-shifting) but travels at c regardless of the stretch.

If an object itself is traveling away from us at the time the light is emmited, then light is also red shifted by this "proper" motion in addition to the expansion of the universe.

rwald
2004-Jan-23, 11:36 PM
I thought the later effect was more prominant than the former? I could be wrong, though.

Sam5
2004-Jan-23, 11:54 PM
All electromagnetic waves travel at the same speed through a vacuum, a value somthing around 300,000 km / s. Einstein says in his theory of relativity that the speed of light is always the same, no matter how fast its source is traveling. Speed of an electromag. wave is just freq. times wavelength. Given this, how is Red Shift possible? Even if the source of light is traveling away from us, the light is still traveling at a constant speed. Does the freq. change as well? Thank you


Einstein said in 1911 that light speed slows down in a gravity field the rate of:

c= c0 (1 - Φ/c^2)

This means that gravity fields act something like a “local ether” or a local light speed regulator. Light slows down in a strong gravity field and speeds up in a weak one.

For a modern version of this theory, see:

LINK (http://www.google.com/search?hl=en&lr=&ie=ISO-8859-1&q=%22local+ether%22+Ching-Chuan+Su+&btnG=Google+Search)

rwald
2004-Jan-24, 12:01 AM
Hmm. I knew that by quantum mechanics, light could be slowed down when passing through a medium (water, glass, etc.), but I thought that gravitational fields only altered the spacetime around them, not the speed of light. Perhaps it's the alteration of time that leads to the appearance of c being slowed?

Sam5
2004-Jan-24, 12:26 AM
Hmm. I knew that by quantum mechanics, light could be slowed down when passing through a medium (water, glass, etc.), but I thought that gravitational fields only altered the spacetime around them, not the speed of light. Perhaps it's the alteration of time that leads to the appearance of c being slowed?


Well, it can be explained in a complicated modern way or in an easy classical way. I prefer the easy classical way. You can see it explained in calculus terms at the end of this 1916 General Relativity paper. Or you can read his vague mentions of it in his 1916 book and the 1952 Appendix V.

Essentially, in 1911 he changed his 1905 “constancy” postulate to be more like this (these are my words): “An atomic clock located inside a gravity field will always measure ‘c’ as the local speed of light when the light is passing the place where the atomic clock is located.”

Seems that atomic clocks slow down inside a gravity field at the same rate light speed slows down inside a gravity field.

But if we use just one atomic clock, located in one place, to measure the speed of light traveling through several different gravity fields of different strengths, then we will measure a variable speed of light.

The gravity field might not be a true “propagating medium” of light or a true “ether”, but it is a local speed regulator for light. I.E., a strong local gravity field slows down the local speed of light. A gravity field acts something like a “medium” for light, in that it slows down the speed of light, and the stronger the field is, the more it slows down the speed of light.

rwald
2004-Jan-24, 12:52 AM
OK. So gravity slows the speed of light because gravity slows time, and since speed is just distance / time, anything which makes time slow down (that is, get "bigger") will make the speed get "smaller." Gotcha.

Sam5
2004-Jan-24, 01:10 AM
OK. So gravity slows the speed of light because gravity slows time, and since speed is just distance / time, anything which makes time slow down (that is, get "bigger") will make the speed get "smaller." Gotcha.



I don’t like that way of explaining it. I prefer the classical way: Light speed slows down in a gravity field and atomic clocks slow down in the same gravity field at the same rate.

Remember, atoms are what emit light. Light comes from atoms. So that is most likely why their rates are tied together.

But an atomic clock does NOT represent all of “time”. It only represents the atomic time, the tick rate of the atom, the internal harmonic oscillation rates of the atoms in the gravity field. This is a function of quantum mechanics law. That law is an “electrodynamics” law, which is different from a large-mass mechanical law. For example, a pendulum clock speeds up in a gravity field where an atomic clock slows down. Why? Two different laws at work. One is a large-size mechanical law and the other one is a small-size electrodynamical law.

So, an atom’s vibration rate doesn’t represent our own human “biological time” any more than a pendulum vibration rate does. Our biological time is based mainly on molecular vibration rates, i.e. thermodynamic time.

Physicists like to go by atomic and light-speed time, while biologists like to go by thermodynamic time.

rwald
2004-Jan-24, 01:25 AM
Hmm. Clearly, a pendulum changes ticks differently near a black hole, but that's because a pendulum's motion depends on an external force. Neither an atomic clock, a light clock, or a biological clock directly rely on external forces to control them. I'm pretty sure that those three clocks correspond to one another almost perfectly.

As far as the view of whether gravity slows light or time, it probably is just a matter of point of view. If gravity slows light, then it slows the motion of light clocks, and any observer in a different frame looking at that light clock will think time is being slowed. If gravity slows time, then since speed is dependent on time, light-speed is also slowed. Must be another one of those things that can be interpreted two different ways, but which are both the same physical event.

George
2004-Jan-24, 01:48 AM
I thought the later effect was more prominant than the former? I could be wrong, though.

Yes. :)

I think I'm right here...

If the light is from a nearby star, it's redshift will be more from the star’s proper motion than from space expansion. Some stars are close enough to show slight blueshifts since they are traveling more towards us than away. However, over long distances/time, light is more stretched by the expansion of space.

Imagine being outside in the wind and throwing a Nerf ball to someone. If they are close to you, the speed of your throwing hand (proper motion) determines what the receiver catches. However, if they are far away and it is windy (space expansion)....yep, it’s the wind that dominates the event.

There is also rotational redshift. As stars rotate, one side is redshifted and the other side is blue shifted relative to its center. This will reveal the star’s rotational speed.

Hopefully, someone will confirm this or nit it. :)

George
2004-Jan-24, 01:50 AM
BTW, Earthman....Welcome to the board! =D> =D>

Sam5
2004-Jan-24, 01:55 AM
Hmm. Clearly, a pendulum changes ticks differently near a black hole, but that's because a pendulum's motion depends on an external force. Neither an atomic clock, a light clock, or a biological clock directly rely on external forces to control them. I'm pretty sure that those three clocks correspond to one another almost perfectly.

No, biological time is heat time, thermodynamic time. That's different from atomic time.

An atom can both speed up and slow down at the same time, i.e. it's molecular vibration rate can speed up while its internal harmonic oscillation rate can slow down. It happens in stars all the time. These are two different kinds of time, thermodynamic time and atomic time.

Sam5
2004-Jan-24, 01:58 AM
Imagine being outside in the wind.....

Ha, ether.

Apparently the gravitational fields act as light "ether", as light speed regulators. Einstein deduced this from his 1911 theory, but he hated calling a gravitational field an "ether". Why? Because he had already gone on record in 1905 saying there was "no ether". He hated to admit he was wrong about anything.

russ_watters
2004-Jan-24, 01:59 AM
Einstein said in 1911 that light speed slows down in a gravity field... Earthman (and apparently rwald as well), as you are new, I'll put this rather succinctly for you: Sam5 is pushing his own personal version of Relativity at odds with Einstein's and the scientific community's understanding. He's going to hijack your thread and turn it into a debate on Relativity. Its unclear if he doesn't understand it or if he's just purposely misrepresenting it, but either way: he's wrong.

Sam5
2004-Jan-24, 01:59 AM
No, Russ is wrong. I back up my new information with the latest physics papers on the subject.

Russ is a, “Einstein Was Never Wrong”, kind of guy, and he hates to admit that the 1905 SR paper had flaws, but, that’s just too bad, because non-American physicists are finally admitting that the 1905 paper contained flaws.

Sam5
2004-Jan-24, 02:05 AM
As far as the view of whether gravity slows light or time, it probably is just a matter of point of view. If gravity slows light, then it slows the motion of light clocks, and any observer in a different frame looking at that light clock will think time is being slowed. If gravity slows time, then since speed is dependent on time, light-speed is also slowed. Must be another one of those things that can be interpreted two different ways, but which are both the same physical event.

I agree. But I would say that gravity slows atomic clocks. That's a function of nature. It's a quantum mechanics and "electrodynamics" function. But atomic time doesn't represent all of time inside any "frame of reference". Ask any biologist.

When you go to a doctor, what is the first thing a nurse does? Measure your internal harmonic oscillation rates? Your body’s “atomic clock”? No. She measures your average thermodynamic time rate with a thermometer.

swansont
2004-Jan-24, 02:34 AM
When you go to a doctor, what is the first thing a nurse does? Measure your internal harmonic oscillation rates? Your body’s “atomic clock”? No. She measures your average thermodynamic time rate with a thermometer.

I'm quite sure she measures your temperature with a thermometer.

Sam5
2004-Jan-24, 02:38 AM
When you go to a doctor, what is the first thing a nurse does? Measure your internal harmonic oscillation rates? Your body’s “atomic clock”? No. She measures your average thermodynamic time rate with a thermometer.

I'm quite sure she measures your temperature with a thermometer.

Right.

Here, read this. A clock man should know about this:

"TIME IN BIOLOGY AND PHYSICS" (http://www.chronos.msu.ru/EREPORTS/smith_time.pdf)

rwald
2004-Jan-24, 03:43 AM
The rate that thermodynamic reactions happen at is dependent on atomic time. If I sat near a black hole, my light clock, atomic clock, and biological clock would all be dialated by the same factor. If I would have lived for 70 years on Earth as measured by an Earth clock, I would live for 70 years near the black hole as measured by my black hole clocks. If there were any difference, I could use that to determine whether I was truly at rest or not, and that would violate the principle of relativity.

Sam5
2004-Jan-24, 04:02 AM
The rate that thermodynamic reactions happen at is dependent on atomic time. If I sat near a black hole, my light clock, atomic clock, and biological clock would all be dialated by the same factor.

Are you saying you would freeze to absolute zero at a black hole? Can you provide some science papers that support your point of view?

What about the crushing factor? Wouldn't you be dead if you received more than 10 or 20 gs of pressure?

Musashi
2004-Jan-24, 04:05 AM
Well, listen to Russ. Sam may or may not understand relativity, but he thinks there is some American conspiracy to protect Einstein or something. Just be careful about taking Sams word on the way things work.

rwald
2004-Jan-24, 04:09 AM
(Sorry Russ, but I'm a sucker for trolls.)

As viewed from the outside, you would never reach the event horizon. As you got closer and closer to it, from the outside view your time would dialate infinitely. You would appear to be forever falling closer, never actually reaching the horizon. So yes, from an outside perspective, you would appear to be at absolute zero.

However, from your own perspective, this is not what would happen. Barring tidal effects temporarily (and looking around, etc.; I mean based on your clocks and meter sticks), you wouldn't know that you were approaching a black hole. You would think your clock was running normally, etc. The crushing would happen when tidal forces became strong enough to squish you infinitely thin along one direction while streaching you infinitely long along the other. Whether this happens before or after the event horizon depends on the mass of the black hole; counterintuitively, the more massive the black hole is, the closer you can get to the event horizon before tidal forces rip you apart (for the really massive ones, you would be ripped apart after you passed the event horizon, though that wouldn't do you much good in the long run.)

Sam5
2004-Jan-24, 04:23 AM
As viewed from the outside, you would never reach the event horizon. As you got closer and closer to it, from the outside view your time would dialate infinitely. You would appear to be forever falling closer, never actually reaching the horizon. So yes, from an outside perspective, you would appear to be at absolute zero.

However, from your own perspective, this is not what would happen. Barring tidal effects temporarily (and looking around, etc.; I mean based on your clocks and meter sticks), you wouldn't know that you were approaching a black hole. You would think your clock was running normally, etc. The crushing would happen when tidal forces became strong enough to squish you infinitely thin along one direction while streaching you infinitely long along the other. Whether this happens before or after the event horizon depends on the mass of the black hole; counterintuitively, the more massive the black hole is, the closer you can get to the event horizon before tidal forces rip you apart (for the really massive ones, you would be ripped apart after you passed the event horizon, though that wouldn't do you much good in the long run.)



Well, if you are at absolute zero, you are dead. Now how is someone going to see you “appear” to be at absolute zero, but you feel yourself still warm?

Some of these kinds of thought experiments become so ridiculous, they are totally useless, except to amaze a few junior-high kids.

I could just as easily sit here and say, “Imagine you have invented a time machine, and you go back to caveman days, then you get chased all over the place by angry cavemen, but all your friends see you frozen in time on their TV monitor down at the time machine lab. And Einstein predicted all this stuff.”

See, I can make up fantasy stuff too.

rwald
2004-Jan-24, 04:30 AM
The point of the example I gave is that not all observers need to observe the same events at the same times. Have you heard of the barn example? If not, I'll go into more detail in a later post, but the gist of it is that in one reference frame, a 5 foot long pole is completely enclosed within a 10 foot long barn for a period of time, while in another frame a 20 foot long pole is at no time enclosed in a 2.5 foot long barn. Both perspectives are right; synchronicity at a distance doesn't exist in a relativistic universe. No one said that everyone has to observer the same things happening at the same time in all places; if that were the case, then the whole time dialation thing wouldn't work.

Sam5
2004-Jan-24, 04:34 AM
No one said that everyone has to observer the same things happening at the same time in all places;

And you think we needed Einstein to tell us that??

Sam5
2004-Jan-24, 04:36 AM
the gist of it is that in one reference frame, a 5 foot long pole is completely enclosed within a 10 foot long barn for a period of time, while in another frame a 20 foot long pole is at no time enclosed in a 2.5 foot long barn. Both perspectives are right;

Yeah, so?

Normandy6644
2004-Jan-24, 05:10 AM
No, Russ is wrong. I back up my new information with the latest physics papers on the subject

Wow Sam. I ask you for this so many times in the relativity thread, and here you are claiming to have it. Like I've said before, if you have evidence that the speed of light can go faster than c, or even is affected by gravity, please share it. No opinions, nothing else, just a link to an experiment verifying this. If you post anything other than that, I will assume you don't have it.

Musashi
2004-Jan-24, 07:23 AM
Sam is busy, I will post in his stead:

Normandy, can you answer my question? If two people pass each other, and one person sees the other has a temperature of a few degrees Kelvin, how come the other person is still alive?

Do you have a solution for the Twins paradox? You should call NASA and share! LOL!

rwald
2004-Jan-24, 10:28 AM
Twin Paradox solution in 30 words:

The twin who turns around feels an acceleration; the twin at home doesn't. The two twins aren't equal. The twins do not expect their ages to be equal. QED.

Tempurature solution:

I never said that they're passing each other in a symmetric situation. I said one is falling into a black hole, and the other isn't. Now, the time at which the person falling in thinks he passes the event horizon is t' = 0. The time the observer outside the black hole thinks this happens is t = infinity. The person falling in does not believe his temperature to be 0 K at any point. But then again, he doesn't think his clock is slowing either. The person outside the black hole thinks the falling person's clock is dialating towards infinity, and their tempurature is dropping to zero. These two effects are not unrelated. Temperature is just an average quantity of heat, and heat is vibrations. If something is frozen in time, it can have no vibrations. The person outside the black hole effectively sees the person to be frozen in time and therefore frozen in tempurature as well.

Though the gravity-slowing-c thing may or may not be a completely accurate picture of things, I'm going to grant it temporarily to demonstrate how the above effect happens. Let's say that the falling observer is carrying a clock that sends out a light pulse every second, and that this is how the outside observer can tell the falling person's time. Now, initially the light pulses are spaced evenly, when the falling observer isn't yet close enough to the black hole for its effects to be felt (I'm neglecting special relativity here, because that's more calculation than I want to do). However, as he gets closer to the black hole, two things start to happen: the light pulses come less and less frequently, and they have less energy. The first is because when they're closer to the black hole, they move slower, and because every second (by the falling observer's time) the falling observer gets closer to the black hole, every succeding pulse passes through more and more of the c-slowing region, so every pulse gets held back more than the one before it. Also, each pulse has less energy than the ones before it. The reason is that in order for each light pulse to reach the observer outside the black hole, it must escape the hole's gravitational energy well. The deeper into the well the pulse starts, the more energy it must give up in order to escape the well. So, given that the light pulses come more slowly and with less energy as time goes on, the appearance of the falling person to eventually freeze in time and tempurature makes sense. Since at the event horizon, the light pulse would never escape, a pulse emitted just before passing the horizon would take nearly forever to escape. So after an arbitrarily long period of time, you would just be seeing the pulses that were emitted very shortly before passing the horizon. As for tempurature: If these pulses, instead of click from a clock, were the amount of radiation emitted from the person's body as a result of that person's heat, when the energy in that radiance goes to zero, so does their tempurature. So the outside observer sees the falling person to take an infinite amount of time to reach the horizon, and sees the person as approching absolute zero as this happens.

Note that all of the above discussion related to what the outside observer sees. The falling person still sees his time as running normally and his tempurature as staying normal. It's only when tidal forces tear him apart that he begins to get concerned.

If after this explanation, you still don't understand the black hole thing, I'm not sure there's much more I can do.

swansont
2004-Jan-24, 01:04 PM
When you go to a doctor, what is the first thing a nurse does? Measure your internal harmonic oscillation rates? Your body’s “atomic clock”? No. She measures your average thermodynamic time rate with a thermometer.

I'm quite sure she measures your temperature with a thermometer.

Right.

Here, read this. A clock man should know about this:

"TIME IN BIOLOGY AND PHYSICS" (http://www.chronos.msu.ru/EREPORTS/smith_time.pdf)

Noting that humans don't perceive time uniformly, and paramaterizing terms and calling them "time" is mathematical convenience. Extending that to saying that these systems "have their own spacetime" - well, saying it don't make it so.


No, biological time is heat time, thermodynamic time. That's different from atomic time.

Note that your linked paper differentiates between "thermodynamic time" and "biological time." Not even your source claims they are the same.

Tensor
2004-Jan-24, 02:43 PM
All electromagnetic waves travel at the same speed through a vacuum, a value somthing around 300,000 km / s. Einstein says in his theory of relativity that the speed of light is always the same, no matter how fast its source is traveling. Speed of an electromag. wave is just freq. times wavelength. Given this, how is Red Shift possible? Even if the source of light is traveling away from us, the light is still traveling at a constant speed. Does the freq. change as well? Thank you


Einstein said in 1911 that light speed slows down in a gravity field the rate of:

c= c0 (1 - Φ/c^2)

Actually, it has been explained to Sam5 that the equation above is not completely correct, as the full GR equation is different. The 1911 equation was just a step to the full GR theory.


This means that gravity fields act something like a “local ether” or a local light speed regulator. Light slows down in a strong gravity field and speeds up in a weak one.

Actually, it has been explained to Sam5 several times that aether and fields don't act the same.


For a modern version of this theory, see:

LINK (http://www.google.com/search?hl=en&lr=&ie=ISO-8859-1&q=%22local+ether%22+Ching-Chuan+Su+&btnG=Google+Search)

Actually, Sam5 is being intelectually dishonest here, as he has been show this quote from the author of "modern version of he theory":




"It is seen that the two Bragg reflections are asymmetric, as predicted by the local-ether model. However, the agreement is not good quantitatively. "

Which means his new "theory" doesn't match with current observations, and so, doesn't work.

Sam5
2004-Jan-24, 03:19 PM
Sam may or may not understand relativity, but he thinks there is some American conspiracy to protect Einstein or something. Just be careful about taking Sams word on the way things work.

Maybe you can clear everything up by explaining something to me. Here’s the situation. It’s very simple:

An atomic clock ticks slow in a valley and fast on a mountain.

An atomic clock in a valley will measure “c” as the speed of a horizontal beam of light in a valley.

An atomic clock on a mountain will measure “c” as the speed of a horizontal beam of light on a mountain.

This means the speed of the light beam in a valley is moving slower than the speed of the light beam on the mountain.

This means the speed of light is variable at different places in a gravity field, and Einstein said so in his 1911 paper and his 1916 book.

So why is this variable speed of light such a big secret in science today?

Sam5
2004-Jan-24, 03:24 PM
Twin Paradox solution in 30 words:

The twin who turns around feels an acceleration; the twin at home doesn't. The two twins aren't equal. The twins do not expect their ages to be equal. QED.


That means the 1905 SR theory is wrong, since it did not consider the effects of acceleration.

George
2004-Jan-24, 03:51 PM
That means the 1905 SR theory is wrong, since it did not consider the effects of acceleration.

I thought the 1905 [paper] restricted itself to uniform motion only. If so, why would it be wrong?

Sam5
2004-Jan-24, 03:59 PM
That means the 1905 SR theory is wrong, since it did not consider the effects of acceleration.

I thought the 1905 [paper] restricted itself to uniform motion only. If so, why would it be wrong?

The first half of the paper, the Kinematical part, is wrong because it has physical things taking place in one system as a result of just the “relative motion” of two systems. This is impossible. There must be some sort of physical interaction between the two systems before they can influence each other and cause things to happen in each other. The physical action can be direct physical contact, or by means of field interactions. But it can’t happen just because of “relative motion”.

Einstein corrected the main error in the 1905 paper when he added a gravity field to one of the systems in 1918, and then the "relative motion" became unimportant. After 1918, the two systems didn't have to move "relatively" at all. Very few people today know about his 1918 correction to the 1905 paper.

swansont
2004-Jan-24, 04:18 PM
Twin Paradox solution in 30 words:

The twin who turns around feels an acceleration; the twin at home doesn't. The two twins aren't equal. The twins do not expect their ages to be equal. QED.


That means the 1905 SR theory is wrong, since it did not consider the effects of acceleration.

No, it means that since the 1905 paper did not consider the effects of acceleration, it does not predict the effects of acceleration. Since the effects are separate, they can be considered separately.

Sam5
2004-Jan-24, 04:23 PM
No, it means that since the 1905 paper did not consider the effects of acceleration, it does not predict the effects of acceleration. Since the effects are separate, they can be considered separately.

Einstein added acceleration to the 1905 SR theory in 1918 to solve the twins paradox problem, just as rwald added acceleration to it to solve the twins paradox. That is the only way to solve it, by changing the 1905 paper to include acceleration, and that proves the 1905 paper was wrong.

Normandy6644
2004-Jan-24, 04:49 PM
No, it means that since the 1905 paper did not consider the effects of acceleration, it does not predict the effects of acceleration. Since the effects are separate, they can be considered separately.

Einstein added acceleration to the 1905 SR theory in 1918 to solve the twins paradox problem, just as rwald added acceleration to it to solve the twins paradox. That is the only way to solve it, by changing the 1905 paper to include acceleration, and that proves the 1905 paper was wrong.

Haven't we done this already? And Sam, I see you decided not to post your "lastest physics papers" to us, so I'm assuming you don't have any experimental evidence to validate your claim.

russ_watters
2004-Jan-24, 05:54 PM
(Sorry Russ, but I'm a sucker for trolls.) Fair enough. I'm still responding to Sam every now and then too (though not really arguing with him).

Sam5
2004-Jan-24, 06:09 PM
And Sam, I see you decided not to post your "lastest physics papers" to us, so I'm assuming you don't have any experimental evidence to validate your claim.


Why don’t you post your latest paper in which you explain to us how “space expands”.

Does “old space” stretch, or is “new space” added to the old space? Tell us how that works.

Tensor
2004-Jan-24, 08:05 PM
And Sam, I see you decided not to post your "lastest physics papers" to us, so I'm assuming you don't have any experimental evidence to validate your claim.


Why don’t you post your latest paper in which you explain to us how “space expands”.

Hey, Sam5, we've been asking you for your paper, for answers to questions and this:

Sam5 has been claiming SR is wrong. He has been challenged to show us his SR calculations, his calculations using Lorentz's 1895 theory, and his GR calculations(where gravity can be ignored). As soon as he shows us Lorent'z theory calculations match the GR calculations, and the GR calculations don't match the SR calculations, he can claim Lorentz is accurate and SR is not. Notice I'm asking for his calculations, not a cut and paste of an equation. Until he does, he is being intelectually dishonest by claiming SR is wrong.

you haven't provided them.


Does “old space” stretch, or is “new space” added to the old space? Tell us how that works.

It was explained several posts up.

Tensor
2004-Jan-24, 08:09 PM
That means the 1905 SR theory is wrong, since it did not consider the effects of acceleration.

I thought the 1905 [paper] restricted itself to uniform motion only. If so, why would it be wrong?

You are correct here George. However, Sam5 does not accept the 1905 paper. As a result, he claims it is wrong. Of course, he has produced no mathematical proof of this.

Tensor
2004-Jan-24, 08:51 PM
(Sorry Russ, but I'm a sucker for trolls.)

Heheheh, that can be a bad thing.

If you are feeling brave heck out this (http://www.badastronomy.com/phpBB/viewtopic.php?t=9731&start=1800&sid=578ac002e5cb8b d5dc32e86dce90902d)
thread (I started you out on the last page, 73), to see what Sam5 has been saying. rwald, just to save you some time, here are some of Sam5's points

SR is wrong, Lorentz's 1904 theory is correct, GR is correct.
This is interesting because Lorentz uses Aether as an absolute referece frame, and GR doesn't. Thus, the two are incompatible. So either one or the other is wrong, yet he claims they are both right.

He claims that the absolute reference frame of Lorentz is the same as whatever frame you pick in GR.
This indicates that he has yet to grasp the difference between an absolute reference frame and a relative reference frame.

He claims the first part of SR is incorrect, but the second is correct.
He's got several issues here. 1) One is that he refuses to accept the constancy of c where gravity or acceleration can be ignored. 2)He claims that GR fixed SR and won't accept that GR extends, not fixes, SR into regions where gravity or acceleration must be taken into account. 3)He claims that Lorentz was the one that discovered the contraction equation for frame transformations, not Einstein. It has been pointed out to him that George Fiztgerald came up with it first, Lorentz just used it to figure out the amount of contraction in his 1904 paper. There is nothing in the paper to show where that equation came from. On he other hand, Einstein derived the equation from first principles in the 1905 paper.

I have posted this several times:

Sam5 has been claiming SR is wrong. He has been challenged to show us his SR calculations, his calculations using Lorentz's 1895 theory, and his GR calculations(where gravity can be ignored). As soon as he shows us Lorent'z theory calculations match the GR calculations, and the GR calculations don't match the SR calculations, he can claim Lorentz is accurate and SR is not. Notice I'm asking for his calculations, not a cut and paste of an equation. Until he does, he is being intelectually dishonest by claiming SR is wrong.

and he has yet to show this. He continues to post that SR is wrong, Lorentz and GR is correnct.


He continues to post a link to what he calls a "Modern local-ether Theory" that he claims shows that an ether works. What he conviently doesn't share with us (because it has been pointed out to him), is that the author himself, in another paper, admits that his theory doesn't match the current observations, and so, of course , is wrong.

He has posted quotes from papers, either misunderstanding or purposely omitting (I'm not really sure which) other parts of the paper refuting the quote he posts.

I'm sure there are a few more here, but I don't remember them right now. I'll let others expand on this. Just a warning. :)

Cougar
2004-Jan-24, 10:27 PM
But back to the topic of this thread.... and a question about it....

Surprisingly, "space" is expanding (Big Bang Theory) and the light gets stretched. This increases the wavelength and, therefore, lowers the frequency (red-shifting) but travels at c regardless of the stretch.

If an object itself is traveling away from us at the time the light is emmited, then light is also red shifted by this "proper" motion in addition to the expansion of the universe.

I thought the later effect was more prominant than the former? I could be wrong, though.
Now that I read this again, I'm not sure which latter effect you're referring to, rwald! George talked about redshift due to universal expansion first, and he also mentions that last! So I'm totally confused. But to clarify, one cause of redshift is termed doppler redshift, which is caused by the actual motion of one body relative to another (also termed proper motion or peculiar motion). Cosmological redshift is caused by the expansion of space. As [I forget who] mentioned, if the object isn't very far away, the doppler redshift will likely swamp the cosmological redshift. But for very distant objects, the cosmological redshift is typically orders of magnitude larger than the doppler redshift.
http://www.xmission.com/~dcc/cougar.gif

Sam5
2004-Jan-25, 12:28 AM
Hey, Sam5,

Hey, why don’t you guys tell all of us how “space expands”??

Does “old space” stretch, or is “new space” added to the “old space”? If so, then where does the "new space" come from?

Tell us how that works.

I’m tired of hearing this baloney without a scientific explanation of it, so you tell us how it works.

rwald
2004-Jan-25, 12:53 AM
Couger, I had thought that Doppler redshift had a greater effect than cosmological redshift. But I guess that it makes sense for the later (in the order that I stated them in the last sentence) to become more important at greater distances. Though, wouldn't the speeds also increase, making Doppler redshift larger as well?

George
2004-Jan-25, 02:43 AM
It is held that the speed of light is unchanged regardless of time and distance.

Wavelength times frequency equals the speed of light.

λ x f = c

As the wavelength increases (lengthened by redshifting), then the frequency will decrease since it's speed is unchanged. Hmmm, it would be kinda tough to increase wavelength (redden it) and increase frequency (blueshift it). :) I'm glad c is unchanged. :)

Sorry Cougar if I cut in but I think my Nerf ball analogy (pg. 1) messed-up the logic in the speed of light here.

The red shifting due to the Doppler shift in wavelegth is greater than the cosmological shift when the light source is nearby. However, the opposite is true when the light comes from afar (not a Texas "fire" :) ). Over billions of light years distance, the cosmological redshift is extreme.

Tensor
2004-Jan-25, 04:59 AM
But back to the topic of this thread.... and a question about it....


Thank you Cougar. =D>

Normandy6644
2004-Jan-25, 09:26 PM
And Sam, I see you decided not to post your "lastest physics papers" to us, so I'm assuming you don't have any experimental evidence to validate your claim.


Why don’t you post your latest paper in which you explain to us how “space expands”.

Does “old space” stretch, or is “new space” added to the old space? Tell us how that works.

If you would bother to read my post, you would see I was asking for evidence about the speed of light changing on a gravitational field. I thought what you were saying about expanding space was rather interesting. Naturally, you ignored that and went straight into self defense mode, deciding that you are above all forms of questioning. Next time read the other person's post before you start attacking.

Sam5
2004-Jan-25, 11:27 PM
And Sam, I see you decided not to post your "lastest physics papers" to us, so I'm assuming you don't have any experimental evidence to validate your claim.


Why don’t you post your latest paper in which you explain to us how “space expands”.

Does “old space” stretch, or is “new space” added to the old space? Tell us how that works.

If you would bother to read my post, you would see I was asking for evidence about the speed of light changing on a gravitational field. I thought what you were saying about expanding space was rather interesting. Naturally, you ignored that and went straight into self defense mode, deciding that you are above all forms of questioning. Next time read the other person's post before you start attacking.


I think I’ve already explained the “evidence” that the speed of light changes, dozens of times. Einstein said in books and papers that it changed, I linked you to five physics websites/papers that say it changes. When the earth moves toward a star we record a blueshift, when we move away from a star we record a redshift. Our motion doesn’t change the frequency of the light through deep space, but our motion changes the relative velocity of the light from c to c + v back to c and then to c – v, every six months, relative to the earth. What more do you want in the way of evidence? If you don’t understand what I’ve said already, then you’re not going to understand anything else I say.

Normandy6644
2004-Jan-25, 11:32 PM
What more do you want in the way of evidence?

AN EXPERIMENT.

rwald
2004-Jan-25, 11:46 PM
Just a comment: If I'm standing far away from a black hole, and am watching a light clock located near the event horizon, I'll see the light in that light clock as moving more slowly than c. That's because I see time as moving more slowly in that region, and since a light clock measures time, it too must move slowing, and therefore the light in that clock must move more slowly. Of course, were I actually standing next to the clock, it would look normal. But then a light clock far away from the hole would appear to have superluminal light!

If I'm wrong in any of these assertions, I (unlike some people) am open to being corrected.

Sam5
2004-Jan-26, 12:11 AM
Just a comment: If I'm standing far away from a black hole, and am watching a light clock located near the event horizon, I'll see the light in that light clock as moving more slowly than c.

Right, because light speed slows down in a gravity field.

milli360
2004-Jan-26, 12:42 AM
Right, because light speed slows down in a gravity field.
Relative to what? :)

Sam5
2004-Jan-26, 01:12 AM
Right, because light speed slows down in a gravity field.
Relative to what? :)

Relative to the speed it was traveling before it got into the gravity field, as measured by a single clock resting on a planet both before and after it got into the gravity field.

Why are you trying to hide this fact? Einstein mentioned it several times.

milli360
2004-Jan-26, 02:31 AM
Right, because light speed slows down in a gravity field.
Relative to what? :)

Relative to the speed it was traveling before it got into the gravity field, as measured by a single clock resting on a planet both before and after it got into the gravity field.

Why are you trying to hide this fact? Einstein mentioned it several times.
No, no, I'm not trying to hide anything. I'm trying to understand what you're getting at.

When you say, "it got into the gravity field," where was it when it was "outside" the gravity field?

Sam5
2004-Jan-26, 02:50 AM
When you say, "it got into the gravity field," where was it when it was "outside" the gravity field?

Ask the guys who use the term “gravity well” on this thread. Ask them, “Where is ‘outside’ the gravity well?" Maybe they’ll explain it to you.”

milli360
2004-Jan-26, 03:16 AM
When you say, "it got into the gravity field," where was it when it was "outside" the gravity field?

Ask the guys who use the term “gravity well” on this thread. Ask them, “Where is ‘outside’ the gravity well?" Maybe they’ll explain it to you.”
The only post in this thread that uses the term is rwald's, from Saturday (http://www.badastronomy.com/phpBB/viewtopic.php?p=197563#197563):


The reason is that in order for each light pulse to reach the observer outside the black hole, it must escape the hole's gravitational energy well. The deeper into the well the pulse starts, the more energy it must give up in order to escape the well.

If you fall into a well (gravity or water), you can escape by climbing up, but you're still affected by the gravity field when you can stand up again. You won't be "outside" the gravity field.

Tensor
2004-Jan-26, 03:52 AM
When you say, "it got into the gravity field," where was it when it was "outside" the gravity field?

Ask the guys who use the term “gravity well” on this thread. Ask them, “Where is ‘outside’ the gravity well?" Maybe they’ll explain it to you.”


Why Sam5, can't you?

russ_watters
2004-Jan-26, 04:07 AM
I think I’ve already explained the “evidence” that the speed of light changes, dozens of times. Einstein said in books and papers that it changed... Setting aside our disagreement over what Einstein meant, what Einstein said is the theory. Evidence to support the theory comes from experiments.

You have not provided any evidence.
Why Sam5, can't you? Oops - that might reveal the frame of reference issue that Sam doesn't want to talk about.

Sam5, I'm sure this has been explained before, but the fact that if you could see the light, you'd measure it traveling at a speed other than C does not mean the light actually is traveling at a speed other than C. You can't see the light of course because it isn't in the same frame of reference as you are. And since its not in the same frame of reference, your calculation of its speed is invalid for the light in its frame. The second phrase of SR is ...in any inertial frame of reference.

Frame of reference.
Frame of reference.
Frame of reference.
Frame of reference.
Frame of reference.
Frame of reference.
Frame of reference.
Frame of reference.
Frame of reference.
Frame of reference.
Frame of reference.
Frame of reference.
Frame of reference.
Frame of reference.
Frame of reference.

Normandy6644
2004-Jan-26, 04:07 AM
What more do you want in the way of evidence?

AN EXPERIMENT.

No? Too much to ask?

rwald
2004-Jan-26, 04:32 AM
When you say, "it got into the gravity field," where was it when it was "outside" the gravity field?

Ask the guys who use the term “gravity well” on this thread. Ask them, “Where is ‘outside’ the gravity well?" Maybe they’ll explain it to you.”
The only post in this thread that uses the term is rwald's, from Saturday (http://www.badastronomy.com/phpBB/viewtopic.php?p=197563#197563):


The reason is that in order for each light pulse to reach the observer outside the black hole, it must escape the hole's gravitational energy well. The deeper into the well the pulse starts, the more energy it must give up in order to escape the well.

If you fall into a well (gravity or water), you can escape by climbing up, but you're still affected by the gravity field when you can stand up again. You won't be "outside" the gravity field.
Yea, perhaps it would have been more accurate to refer to "an observer far enough away from the black hole that the reletivistic effects on this observer are trivial," rather than "an observer outside of the black hole's gravity well." In any event, whatever frame you personally are in will appear to have light moving at c. If some other frame appears differently, that's a result of time dialation.

milli360
2004-Jan-26, 05:42 AM
Yea, perhaps it would have been more accurate to refer to "an observer far enough away from the black hole that the reletivistic effects on this observer are trivial," rather than "an observer outside of the black hole's gravity well."
I wasn't trying to criticize your post--I was just pointing out to Sam5 that gravity in a well doesn't stop at the edge of the well--but he was talking about being outside of the gravity field.

rwald
2004-Jan-26, 05:48 AM
One thought on that: Theoretically, gravity waves travel at the speed of light. So, if a large quantity of mass were to suddenly come into existance somewhere, you wouldn't know about it until the light from that event could reach you. So until that happened, you would truly be outside of its gravitation field.

Of course, distant quasars that we can see are by definition not outside of our gravitational fields.

Thomas
2004-Jan-26, 10:16 AM
All electromagnetic waves travel at the same speed through a vacuum, a value somthing around 300,000 km / s. Einstein says in his theory of relativity that the speed of light is always the same, no matter how fast its source is traveling. Speed of an electromag. wave is just freq. times wavelength. Given this, how is Red Shift possible? Even if the source of light is traveling away from us, the light is still traveling at a constant speed. Does the freq. change as well? Thank you
The frequency changes inversely to the wavelength, i.e. their product (the speed of light) is constant.

Sam5
2004-Jan-26, 04:20 PM
Yea, perhaps it would have been more accurate to refer to "an observer far enough away from the black hole that the reletivistic effects on this observer are trivial," rather than "an observer outside of the black hole's gravity well."
I wasn't trying to criticize your post--I was just pointing out to Sam5 that gravity in a well doesn't stop at the edge of the well--but he was talking about being outside of the gravity field.

You know very well that I was talking about the strongest part of the gravity field. That’s why light bends when it “passes near the sun”, although its “bending” actually starts quite a distance from the sun, but at the greater distances, we have trouble measuring the bending since it is slow slight. I’ve already said that gravitational fields are everywhere in space, and even the sun’s field is supposed to extend to infinity, but the big “strength change” comes at fairly close distances to the sun.

You are just searching my texts for little defects in wording. That’s all you are doing.

milli360
2004-Jan-26, 06:32 PM
You are just searching my texts for little defects in wording. That’s all you are doing.
Hello? Line two is for you. I'll tell Mr. Kettle that you'll call him back. :)

If you would reconsider the 1905 paper in that frame of mind--trying to understand it, rather than nitpick little defects, you might find you can learn a lot more from Einstein than I can learn from you, or you from me.

In your post, that I responded to (http://www.badastronomy.com/phpBB/viewtopic.php?p=198379#198379), you had a clock entering a gravity field. You've maintained all along it seems that clocks are affected by physical forces, in GR, rather than in a response to changes in spacetime, but I think we've shown that that is not true. Sometimes, our intuitions fail us, and we have to resort to the original formulation of the theory.

Normandy6644
2004-Jan-26, 10:05 PM
What more do you want in the way of evidence?

AN EXPERIMENT.

No? Too much to ask?

It appears so... :roll:

russ_watters
2004-Jan-26, 10:10 PM
What more do you want in the way of evidence?

AN EXPERIMENT.

No? Too much to ask?

It appears so... :roll: Hmm.... you seem to be responding to your own post.

Normandy6644
2004-Jan-26, 10:12 PM
I am, since Sam is deciding not to.

Sam5
2004-Jan-26, 11:16 PM
I am, since Sam is deciding not to.

I’ve already given you experiments, but you don’t understand my answers. It doesn’t do me any good to repeat them, if you don’t understand them the first 20 times. You probably still don’t know how the H-K Westbound flying clocks knew they were moving West. It certainly wasn’t because some mythical observer was “looking at them” from “high above the North Pole”. That’s just a Santa story.

Normandy6644
2004-Jan-27, 01:38 AM
I am, since Sam is deciding not to.

I’ve already given you experiments, but you don’t understand my answers. It doesn’t do me any good to repeat them, if you don’t understand them the first 20 times. You probably still don’t know how the H-K Westbound flying clocks knew they were moving West. It certainly wasn’t because some mythical observer was “looking at them” from “high above the North Pole”. That’s just a Santa story.

More Sam tactics, claiming to have answered a question already when no such answer was given. Post a link to an experiment showing that the velocity of light changes in a gravitational field. Stop telling me I don't understand, because obviously you can't even follow directions.

Sam5
2004-Jan-27, 01:45 AM
Post a link to an experiment showing that the velocity of light changes in a gravitational field.

Ok...

SCROLL DOWN TO HIGHLIGHTED WORDS (http://216.239.57.104/search?q=cache:LVn28bN_Y-AJ:cassfos02.ucsd.edu/physics/ph7/hw/hw6_ans.html+1919+eddington+%22light+slows+down%22 &hl=en&ie=UTF-8)

Sam5
2004-Jan-27, 01:48 AM
Post a link to an experiment showing that the velocity of light changes in a gravitational field.

Here’s some more:

SCROLL DOWN TO HIGHLIGHTED WORDS ON PAGE 9 OF TEXT (http://216.239.57.104/search?q=cache:ZD0GVC0nKd0J:arxiv.org/pdf/physics/0110069+1919+eddington+%22light+slows+down%22&hl=e n&ie=UTF-8)

Normandy6644
2004-Jan-27, 01:51 AM
Post a link to an experiment showing that the velocity of light changes in a gravitational field.

Ok...

SCROLL DOWN TO HIGHLIGHTED WORDS (http://216.239.57.104/search?q=cache:LVn28bN_Y-AJ:cassfos02.ucsd.edu/physics/ph7/hw/hw6_ans.html+1919+eddington+%22light+slows+down%22 &hl=en&ie=UTF-8)

Thank you, this was all I wanted to see. Now, you understand that this doesn't mean that light will travel any faster than c, right? Light has its maximum speed in a vacuum and minimum speed in a singularity.

EDIT: Sam, I apologize if I seemed rude at all, I just did not know of any true experiments that confirmed this prediction, and I wanted to see one. I appreciate your post.

majic
2004-Jan-27, 01:58 AM
The rate that thermodynamic reactions happen at is dependent on atomic time. If I sat near a black hole, my light clock, atomic clock, and biological clock would all be dialated by the same factor.

Are you saying you would freeze to absolute zero at a black hole? Can you provide some science papers that support your point of view?

What about the crushing factor? Wouldn't you be dead if you received more than 10 or 20 gs of pressure?

You could not survive near a black hole in practise since the gravitational/tidal forces would push harder at the end of you closer to the black hole then atmos on the side of your body that are further away. The differences in gravity are small but on a human scale so immense that you would be teared apart in seperate molecules sooner or later, before ever reaching the closer regions.

Now about "time" slowing down when exposed to gravity : this is correct, and has been tested.

One atomic clock on the ground, one atomic click was flewn in an airplane.
There was a measured difference of fractions of a second (I dont remember how small precisely).

Sam5
2004-Jan-27, 02:01 AM
Post a link to an experiment showing that the velocity of light changes in a gravitational field.

YOO HOO, MORE HERE (http://216.239.57.104/search?q=cache:9vkb9u4L3hUJ:arxiv.org/pdf/physics/0303082+%22light+slows+down%22+gravitational+field &hl=en&ie=UTF-8)

Before you shout and yell at me that “it’s really time that slows down”, it is BOTH. Atomic clocks slow down in a gravity field AND light speed slows down in a gravity field. If you want to pretend that light always travels at “c”, you just mention the clock slowdown but not the light speed slowdown.

If you want to claim that “light is always measured traveling at ‘c’” inside a gravity field, you merely measure its LOCAL speed with a LOCAL atomic clock, and that clock will measure “c” for the light photons moving at that clock.

But if you want to point out to someone that the light actually does slow down in a gravity field, you use a clock that is not located in the field the light travels through. For example, you use an earth based clock to measure the light speed slowdown as a light beam passes the sun. The NASA people know it slows down when it passes the sun, because they use earth-based atomic clocks as their main time standard.

Sam5
2004-Jan-27, 02:09 AM
Thank you, this was all I wanted to see. Now, you understand that this doesn't mean that light will travel any faster than c, right? Light has its maximum speed in a vacuum and minimum speed in a singularity.

EDIT: Sam, I apologize if I seemed rude at all, I just did not know of any true experiments that confirmed this prediction, and I wanted to see one. I appreciate your post.

That’s ok, don’t worry about it. I guess I’m not the best explainer in the world.

Tensor
2004-Jan-27, 03:03 AM
You are just searching my texts for little defects in wording. That’s all you are doing.

Finding the little defects in your wording isn't a big deal, due to the large defects in the meaning of what you are saying.

Sam5
2004-Jan-27, 04:11 AM
Finding the little defects in your wording isn't a big deal, due to the large defects in the meaning of what you are saying.

Why don’t you summarize what I’m saying, and we’ll see if you’ve been paying attention.

Tensor
2004-Jan-27, 04:42 AM
Finding the little defects in your wording isn't a big deal, due to the large defects in the meaning of what you are saying.

Why don’t you summarize what I’m saying, and we’ll see if you’ve been paying attention.

Lorentz's 1904 theory works. The first part of Einstein's 1905 paper doesn't work, the rest of the paper he ripped off from Lorentz. He fixed the 1905 paper in 1918, with a concept he used in a 1911 paper. GR works. Dr. Su's theory is good.

freddo
2004-Jan-27, 05:06 AM
Lorentz's 1904 theory works. The first part of Einstein's 1905 paper doesn't work, the rest of the paper he ripped off from Lorentz. He fixed the 1905 paper in 1918, with a concept he used in a 1911 paper. GR works. Dr. Su's theory is good.

And yet all of these statements are disagreed with.

russ_watters
2004-Jan-27, 07:05 AM
If you want to claim that “light is always measured traveling at ‘c’” inside a gravity field, you merely measure its LOCAL speed with a LOCAL atomic clock, and that clock will measure “c” for the light photons moving at that clock.

But if you want to point out to someone that the light actually does slow down in a gravity field, you use a clock that is not located in the field the light travels through. For example, you use an earth based clock to measure the light speed slowdown as a light beam passes the sun. The NASA people know it slows down when it passes the sun, because they use earth-based atomic clocks as their main time standard. I explained in more detail in the other thread, but no one here has any problem with this interpretation. Its you who doesn't understand the implication: that because of this, the only really meaningful C measurement is the one in the light's frame. If you're going to measure C with a distance in one frame and a time in another, you can pick them arbitrarily to get any speed you want - and that gives you pretty much nothing of value.

That's why SR is worded: 'the speed of light is constant in any inertial frame of reference'.

Tensor
2004-Jan-27, 01:46 PM
Lorentz's 1904 theory works. The first part of Einstein's 1905 paper doesn't work, the rest of the paper he ripped off from Lorentz. He fixed the 1905 paper in 1918, with a concept he used in a 1911 paper. GR works. Dr. Su's theory is good.

And yet all of these statements are disagreed with.

Not quite freddo, he did the the GR works part right. But, one out of seven isn't a good average.

Sam5
2004-Jan-27, 03:13 PM
That's why SR is worded: 'the speed of light is constant in any inertial frame of reference'.

No, the first way he stated the postulate in the second paragraph of his paper was:

“light is always propagated in empty space with a definite velocity c”

But in his 1911 paper and in his 1916 book he revealed that this is not correct, since light slows down inside a strong gravity field. And he finally realized that space is not “empty” because they contain “fields” and the “fields” regulate the speed of light as it travels through space.

The original postulate is suitable for the old 19th Century “universal ether” theory, such as in the Lorentz theory, and in the SR theory Einstein had observers “shrivel up” and their time “dilate” so when they moved through the universal ether, they would always measure the speed of light as “c”. But this didn’t work out because of light slow-down in a strong gravity field. People who claim the SR theory has no flaws have been trying to reword the postulate for the past 98 years in an attempt to get it to work out in a single simple sentence, but they generally forget to include the part about light-speed slow-down in a strong gravity field, which is what GR theory contains.

He didn't use the term "inertial frames" in the 1905 paper.

rwald
2004-Jan-27, 09:37 PM
Correct me if I'm wrong, but I've always been told that Special Relativity explicitely only applies when there are no accelerations or gravitational fields. If you're claiming that Einstein didn't realize this at the time, but only added it later, that would at worst mean that Einstein realized his error after thinking about it some more; Special Relativity (with the provision that it only works without acceleration or gravity) would be just as valid as we all claim it is.

At that point, it just becomes a matter of reading the original documents.

milli360
2004-Jan-27, 10:04 PM
Correct me if I'm wrong, but I've always been told that Special Relativity explicitely only applies when there are no accelerations or gravitational fields.
Actually, in his original 1905 paper, Einstein did apply it to a situation where there are accelerations--changes from one inertial reference frame to other non-equivalent ones--and that is the problem that Sam5 has been complaining about for years. He disputes the ability of Einstein to do that, and he has said it is a mistake, and the conclusions that Einstein drew from doing that are erroneous.

Except the math is straightforward, and correct, and the applicatoin is not in error--it even agrees with GR, which Sam5 accepts as a valid theory. The problem, as I see it, is that Sam5 refuses to accept that an understanding of the math involved will resolve the problem.

Those who do understand the math do not see it as a problem. Sam5 insists that the change of intertial reference frames must be ignored--since SR only applies to inertial reference frames. But Einstein only applied it to inertial reference frames--but applied it in sequence. And then speculated that it could be followed to the limit. That's not an unusual method in calculus, but Sam5 does not understand it.

Have I mischaracterized your position at any point, Sam5?

freddo
2004-Jan-27, 10:51 PM
Not quite freddo, he did the the GR works part right. But, one out of seven isn't a good average.


Ooh, I missed that one hiding in there!! #-o

Sam5
2004-Jan-28, 01:15 AM
Actually, in his original 1905 paper, Einstein did apply it to a situation where there are accelerations--

No, you are making that up.

Einstein said in his 1905 paper:

"let a constant velocity c be imparted"

"two systems of coordinates in uniform translatory motion"

"and that a uniform motion of parallel translation with velocity v along the axis of x"

"with velocity v relatively to system K"

"moves with velocity - v on the axis of X"

"must depend only on the velocity"

"moving relatively to the system K with velocity v"

"viewed from a system in uniform motion"

"the clock at A is moved with the velocity v"

So, it is obvious to most people that he did not consider any accelerative effects in the 1905 paper, which is also what he stated in several other papers and his 1916 book. No “acceleration” considered in SR theory.

You need it so you just add it.

Pauli said about this in his 1921 paper:


“If we take the special case where [clock] C2 is moving along the x-axis to point Q and then back again to P, with discontinuous velocity changes at P and Q, then the effect of the acceleration will certainly be independent of t and can easily be eliminated.”

So there is no acceleration or accelerative effects considered in the 1905 paper.

You need it so you just add it.

The 1905 paper seems to be a kind of “do it yourself” paper. Add what you like, remove what you want, glue something to it, chip something off of it, and use it as you wish. It’s sort of like duct tape. It serves a lot of purposes and can be cut and twisted any way you want to twist it.

freddo
2004-Jan-28, 01:19 AM
The 1905 paper seems to be a kind of “do it yourself” paper. Add what you like, remove what you want, glue something to it, chip something off of it, and use it as you wish. It’s sort of like duct tape. It serves a lot of purposes and can be cut and twisted any way you want to twist it.
And it only appears that way to you as you fail to understand the math.

Sam5
2004-Jan-28, 01:22 AM
But Einstein only applied it to inertial reference frames--but applied it in sequence. And then speculated that it could be followed to the limit. That's not an unusual method in calculus, but Sam5 does not understand it. :^o <<<<[emoticon added by Sam]

Have I mischaracterized your position at any point, Sam5?


Oh, come on man, we went over that nearly 4 years ago. He didn’t even consider the acceleration of the motion in the curve. He just left it out. He was talking about an infinite number of infinitely short lines and an infinite number of turns, but with the accelerative effects left out. That is another reason his paper was criticized and laughed at so much throughout Europe when it was first published. You can’t move a clock in a “closed curve” and then leave out the accelerative effects on the clock, but Einstein did.

Sam5
2004-Jan-28, 01:26 AM
The 1905 paper seems to be a kind of “do it yourself” paper. Add what you like, remove what you want, glue something to it, chip something off of it, and use it as you wish. It’s sort of like duct tape. It serves a lot of purposes and can be cut and twisted any way you want to twist it.
And it only appears that way to you as you fail to understand the math.

There are no accelerative or gravitation terms in any of his 1905 math equations. All relative speeds and velocities are “v”.

Tensor
2004-Jan-28, 02:52 AM
There are no accelerative or gravitation terms in any of his 1905 math equations. All relative speeds and velocities are “v”.

How many times have you've been told that SR does not include gravity?

Sam5
2004-Jan-28, 03:48 AM
There are no accelerative or gravitation terms in any of his 1905 math equations. All relative speeds and velocities are “v”.

How many times have you've been told that SR does not include gravity?

I was talking specifically to freddo, not to you. I was responding to his remark, not yours. Take a number and wait your turn.

freddo
2004-Jan-28, 03:53 AM
I was talking specifically to freddo, not to you. I was responding to his remark, not yours. Take a number and wait your turn.
I know you're not talking to me right now, but I don't care. This is a public forum - if you wanted no one but me to reply, use a PM. Otherwise, don't cry foul if someone decides to drop a comment on your words. Got it?

Sam5
2004-Jan-28, 03:55 AM
I was talking specifically to freddo, not to you. I was responding to his remark, not yours. Take a number and wait your turn.
I know you're not talking to me right now, but I don't care. This is a public forum - if you wanted no one but me to reply, use a PM. Otherwise, don't cry foul if someone decides to drop a comment on your words. Got it?

So you guys like to work in packs?

Tensor
2004-Jan-28, 03:58 AM
There are no accelerative or gravitation terms in any of his 1905 math equations. All relative speeds and velocities are “v”.

How many times have you've been told that SR does not include gravity?

I was talking specifically to freddo, not to you. I was responding to his remark, not yours. Take a number and wait your turn.

And I was responding to your post.

freddo
2004-Jan-28, 04:03 AM
So you guys like to work in packs?Don't be stupid. A discussion board would be a boring place if it were a conversation between two.
Secondly, just because you are confronted with universal dissent does not mean people are conspiring against you. Maybe entertain the possibility that everyone disagrees for their own reasons.

Sam5
2004-Jan-28, 04:17 AM
So you guys like to work in packs?Don't be stupid. A discussion board would be a boring place if it were a conversation between two.
Secondly, just because you are confronted with universal dissent does not mean people are conspiring against you. Maybe entertain the possibility that everyone disagrees for their own reasons.

I wouldn’t call the rude remarks of five grumpy and impolite guys, out of 6 1/2 billion earth inhabitants, “universal dissent”. And you 5 guys certainly aren’t “everyone”. But you do have enormous egos. Enough for a few hundred thousand people at least.

Sam5
2004-Jan-28, 04:20 AM
And I was responding to your post.

My post referred to Milli’s contention that “acceleration” is considered in SR theory. He is wrong. I'm glad you agree with me.

freddo
2004-Jan-28, 04:22 AM
I wouldn’t call the rude remarks of five grumpy and impolite guys, out of 6 1/2 billion earth inhabitants, “universal dissent”. And you 5 guys certainly aren’t “everyone”. But you do have enormous egos. Enough for a few hundred thousand people at least.

Universal dissent taken in the context of this board. I haven't seen anyone pipe up here and say "Bravo Sam5, thankyou for tearing down the myth covering Einstein's 1905 sham!" =D>

:roll:

And I don't think it's prudent to get into a discussion on ego size...


Pot this is kettle, come in pot...

Musashi
2004-Jan-28, 04:27 AM
Kettle this is pot, I read you loud and clear.

Sam5
2004-Jan-28, 04:28 AM
I wouldn’t call the rude remarks of five grumpy and impolite guys, out of 6 1/2 billion earth inhabitants, “universal dissent”. And you 5 guys certainly aren’t “everyone”. But you do have enormous egos. Enough for a few hundred thousand people at least.

Universal dissent taken in the context of this board. I haven't seen anyone pipe up here and say "Bravo Sam5, thankyou for tearing down the myth covering Einstein's 1905 sham!" =D>

A lot of people don't like to irritate or be attacked by packs. I don't care. It doesn't bother me. And lurkers are learning.

freddo
2004-Jan-28, 04:28 AM
Kettle this is pot, I read you loud and clear.


Pot, you are black! Kettle out.

freddo
2004-Jan-28, 04:30 AM
A lot of people don't like to irritate or be attacked by packs. I don't care. It doesn't bother me. And lurkers are learning.
I sure hope they are. As you demonstrate, there are some gross misunderstandings of relativity out there.

Tensor
2004-Jan-28, 04:42 AM
And I was responding to your post.

My post referred to Milli’s contention that “acceleration” is considered in SR theory. He is wrong. I'm glad you agree with me.

exactly where did I say that acceleration wasn't part of the 1905 paper?

russ_watters
2004-Jan-28, 04:54 AM
Kettle this is pot, I read you loud and clear.


Pot, you are black! Kettle out. Sink rate! Sink rate! Pull up. Pot, pull up!

Sam5
2004-Jan-28, 04:54 AM
And I was responding to your post.

My post referred to Milli’s contention that “acceleration” is considered in SR theory. He is wrong. I'm glad you agree with me.

exactly where did I say that acceleration wasn't part of the 1905 paper?

You said, “How many times have you've been told that SR does not include gravity?”

What about the “equivalence principle”? Is that out today? Is it in when you need it to be in and out when you need it to be out?

Anyway, gravity was put in the 1905 theory in 1918.

Tensor
2004-Jan-28, 05:07 AM
And I was responding to your post.

My post referred to Milli’s contention that “acceleration” is considered in SR theory. He is wrong. I'm glad you agree with me.

exactly where did I say that acceleration wasn't part of the 1905 paper?

You said, “How many times have you've been told that SR does not include gravity?”

What about the “equivalence principle”? Is that out today? Is it in when you need it to be in and out when you need it to be out?

Equivalence principle wasn't until 1915. We're talking about the 1905 paper.

Sam5
2004-Jan-28, 05:15 AM
And I was responding to your post.

My post referred to Milli’s contention that “acceleration” is considered in SR theory. He is wrong. I'm glad you agree with me.

exactly where did I say that acceleration wasn't part of the 1905 paper?

You said, “How many times have you've been told that SR does not include gravity?”

What about the “equivalence principle”? Is that out today? Is it in when you need it to be in and out when you need it to be out?

Equivalence principle wasn't until 1915. We're talking about the 1905 paper.

Yeah, but you said “gravity” after 1915, so the equivalence principle applies to what you said.

So you think the 1905 theory has "acceleration" but no "gravity", even though Einstein said in 1916 that it contained no gravity or acceleration?

freddo
2004-Jan-28, 05:18 AM
Yeah, but you said “gravity” after 1915, so the equivalence principle applies to what you said.

Don't lie:


How many times have you've been told that SR does not include gravity?
There is no mention of 1915.

milli360
2004-Jan-28, 06:12 AM
Actually, in his original 1905 paper, Einstein did apply it to a situation where there are accelerations--

No, you are making that up.

No, I'm not. We've talked about it before, but you disagree, because you cannot understand the math.


So there is no acceleration or accelerative effects considered in the 1905 paper.

You need it so you just add it.

Einstein has a closed path along which the reference frames are fixed in speed and direction--but at the points where they intersect, times can be synchronized, because of the proximity. It's one of his premises. He does exactly that--even though you cannot change inertial reference frames like that without accelerating. It's allowed because of his definitions--so it's not inconsistent. And in doing so he does treat the example which has accelerated movement.

I didn't add that to his paper. The paper was long lost but we found it again--and anybody can read it. Even in German.

Sam5
2004-Jan-28, 03:15 PM
Actually, in his original 1905 paper, Einstein did apply it to a situation where there are accelerations--

No, you are making that up.


No, I'm not. We've talked about it before, but you disagree, because you cannot understand the math.

Lol, that’s funny. The equation he used for the “closed curve” experiment was 1/2tv^2/c^2. Can you point out the term for acceleration?

He said in subsequent papers and his book that he didn’t consider “acceleration” in the 1905 paper, so that means he just didn’t consider the accelerative effects of the motion in the closed curve. There is no term for acceleration in his equation for the motion. In fact, he was using mechanical clocks in that thought experiment, and I don’t think he every produced any equations that were used to calculate the accelerative stress effects on mechanical clocks. He didn’t add the atomic clocks to the 1905 paper until 1918, so there are no accelerative effects considered in 1905. Of course if you are thinking of the revised paper, the non-SR version, the “new and improved” 1918 GR version of the paper, then you need to say the k frame clock is an atomic clock and is resting in a gravity field. But there are no accelerative effects considered in the original paper.

milli360
2004-Jan-28, 05:46 PM
Actually, in his original 1905 paper, Einstein did apply it to a situation where there are accelerations--

No, you are making that up.


No, I'm not. We've talked about it before, but you disagree, because you cannot understand the math.

Lol, that’s funny. The equation he used for the “closed curve” experiment was 1/2tv^2/c^2. Can you point out the term for acceleration?
There is none. Never said there was.


He said in subsequent papers and his book that he didn’t consider “acceleration” in the 1905 paper, so that means he just didn’t consider the accelerative effects of the motion in the closed curve.
True, but a closed curve is accelerated. I think we can agree on that.

There is no term for acceleration in his equation for the motion.
Agreed.

In fact, he was using mechanical clocks in that thought experiment, and I don’t think he every produced any equations that were used to calculate the accelerative stress effects on mechanical clocks. He didn’t add the atomic clocks to the 1905 paper until 1918, so there are no accelerative effects considered in 1905.
They weren't part of the equations, yes, but they are definitely there in that peculiar consquence.

Of course if you are thinking of the revised paper, the non-SR version, the “new and improved” 1918 GR version of the paper, then you need to say the k frame clock is an atomic clock and is resting in a gravity field.
I am only thinking of the 1905 paper, and only the first few sections. The ones that you say are in error.

But there are no accelerative effects considered in the original paper.
Of course there are. You just think that he handled them wrongly. You've said that, since every piece of that closed curve is in an inertial reference frame, he must, and should have, reached a conclusion different than the one he reached. I see it differently, because I can understand the math.

That is the basic misunderstanding on your part.

I am not "making up" the fact that he did apply his 1905 theory to a situation which had accelerated elements--motion around a closed curve is accelerated. I don't think anyone, including you, has denied that. You just think he violated his own terms. I do not.

Sam5
2004-Jan-28, 06:08 PM
True, but a closed curve is accelerated. I think we can agree on that.


Yes, you know that, I know that, and he knew that. But in 1905 he just didn’t consider the accelerative effects on the mechanical clocks. That is allowable in thought experiments, although such experiments sometimes lead to errors in conclusions. So there is no “acceleration” in 1905 SR theory until he added it in 1918.

In the 1905 paper, the German word he used was “Geschwindigkeit", which has been translated as “velocity”, but it also can mean “speed” in German, and I think it should be translated as “speed” in English.


They weren't part of the equations, yes, but they are definitely there in that peculiar consquence.

No, not in his thought experiments. They might be there in yours, but they weren't in his.

Sam5
2004-Jan-28, 06:18 PM
But there are no accelerative effects considered in the original paper.
Of course there are. You just think that he handled them wrongly. You've said that, since every piece of that closed curve is in an inertial reference frame, he must, and should have, reached a conclusion different than the one he reached. I see it differently, because I can understand the math.


I’m really glad you can, since 1/2tv^2/c^2 is not a very difficult equation. I know you’re very proud of being able to understand it.

I’m saying that “relative motion” alone can not influence the tick rate of a relatively moving clock. He later realized his error about that and he added the gravity field and atomic clocks to the k frame in 1918.

One of the problems with understanding this stuff is trying to figure out what the guy was thinking. He often said things that don’t seem to make sense, unless we understand the context and what he was thinking about it. And what he was thinking about in the “closed curve” sentence was just leaving out the out the accelerative effects. I’ve read stuff by professors who claim that “acceleration” is IN the 1905 paper because of his “closed curve” remark, but they don’t realize that he just didn’t count it or calculate the accelerative effects. You might and I might, but in 1905 he didn’t because he was talking about his ideas about “relative motion” only, not about “accelerative effects on mechanical clocks”.

milli360
2004-Jan-28, 07:06 PM
True, but a closed curve is accelerated. I think we can agree on that.


Yes, you know that, I know that, and he knew that. But in 1905 he just didn’t consider the accelerative effects on the mechanical clocks. That is allowable in thought experiments, although such experiments sometimes lead to errors in conclusions. So there is no “acceleration” in 1905 SR theory until he added it in 1918.
I didn't say in the theory. I said it was treated, in the paper--you said it wasn't, and I disagreed.


In the 1905 paper, the German word he used was “Geschwindigkeit", which has been translated as “velocity”, but it also can mean “speed” in German, and I think it should be translated as “speed” in English.
LOL. How many emails did we exchange, where I tried to convince you of just that very thing?



They weren't part of the equations, yes, but they are definitely there in that peculiar consquence.

No, not in his thought experiments. They might be there in yours, but they weren't in his.
Motion around a closed curve is accelerated. And it's in that thought experiment he called the "peculiar consequence."




But there are no accelerative effects considered in the original paper.
Of course there are. You just think that he handled them wrongly. You've said that, since every piece of that closed curve is in an inertial reference frame, he must, and should have, reached a conclusion different than the one he reached. I see it differently, because I can understand the math.

I’m really glad you can, since 1/2tv^2/c^2 is not a very difficult equation. I know you’re very proud of being able to understand it.
Not all the math is in the form of equations.


One of the problems with understanding this stuff is trying to figure out what the guy was thinking. He often said things that don’t seem to make sense, unless we understand the context and what he was thinking about it. And what he was thinking about in the “closed curve” sentence was just leaving out the out the accelerative effects. I’ve read stuff by professors who claim that “acceleration” is IN the 1905 paper because of his “closed curve” remark, but they don’t realize that he just didn’t count it or calculate the accelerative effects. You might and I might, but in 1905 he didn’t because he was talking about his ideas about “relative motion” only, not about “accelerative effects on mechanical clocks”.
Well, his calculations are in the same vein as mine, for the same reasons, so I'm pretty sure that you haven't yet figured out what he was thinking.

I thought you didn't like that sort of thing, when other people did it to you? Let's just take the paper at face value, let it speak for itself.

The conclusion I draw from it is that it is not inconsistent.

Sam5
2004-Jan-28, 11:37 PM
So there is no “acceleration” in 1905 SR theory until he added it in 1918.

I didn't say in the theory. I said it was treated, in the paper--you said it wasn't, and I disagreed.


What do you mean "treated"?





In the 1905 paper, the German word he used was “Geschwindigkeit", which has been translated as “velocity”, but it also can mean “speed” in German, and I think it should be translated as “speed” in English.


LOL. How many emails did we exchange, where I tried to convince you of just that very thing?


Maybe 100. Maybe 200. I'm glad you were right about something. Why do you suppose the two English versions mistranslate that word?

Sam5
2004-Jan-28, 11:40 PM
Motion around a closed curve is accelerated. And it's in that thought experiment he called the "peculiar consequence."

No, he means the whole set of thought experiments where the two clocks get together and one "lags behind" the other.

Sam5
2004-Jan-28, 11:43 PM
Well, his calculations are in the same vein as mine, for the same reasons, so I'm pretty sure that you haven't yet figured out what he was thinking.

I thought you didn't like that sort of thing, when other people did it to you? Let's just take the paper at face value, let it speak for itself.

The conclusion I draw from it is that it is not inconsistent.

If it was not inconsistent, he would not have had to add the gravity field in 1918.

Say, do you have an English copy of the 1918 paper?

freddo
2004-Jan-28, 11:52 PM
If it was not inconsistent, he would not have had to add the gravity field in 1918.

Newtonian Mechanics = incomplete, not internally inconsistent.
Special Relativity = incomplete, not internally inconsistent.
General Relativity = incomplete, not internally inconsistent.

Chip
2004-Jan-29, 01:38 AM
Newtonian Mechanics = incomplete, not internally inconsistent.
Special Relativity = incomplete, not internally inconsistent.
General Relativity = incomplete, not internally inconsistent.

Hi freddo,

That is also a condensed summary of the history of scientific theories. Something that is basically accepted, even by some of the people who developed those theories. :wink:

freddo
2004-Jan-29, 01:43 AM
That is also a condensed summary of the history of scientific theories. Something that is basically accepted, even by some of the people who developed those theories.

Well we know that the new theories are not developed because the original ones are actually wrong. If they didn't have some level of applicability they would not have been held in esteem in the first place. Things are essentially built on, not discarded. Theres plenty of chaff for that.

Chip
2004-Jan-29, 01:52 AM
...new theories are not developed because the original ones are actually wrong. If they didn't have some level of applicability they would not have been held in esteem in the first place. Things are essentially built on, not discarded. Theres plenty of chaff for that.

I agree. Along those lines I'd line to recommend a book (by one of your countrymen) for anyone following this thread:

"About Time" by physicist Paul Davies
http://www.amazon.com/exec/obidos/tg/detail/-/0684818221/

Sam5
2004-Jan-29, 01:57 AM
That is also a condensed summary of the history of scientific theories. Something that is basically accepted, even by some of the people who developed those theories.

Well we know that the new theories are not developed because the original ones are actually wrong. If they didn't have some level of applicability they would not have been held in esteem in the first place. Things are essentially built on, not discarded. Theres plenty of chaff for that.

Who told you that??

The histories of biology, geology, physics, and astronomy are filled with theories that were wrong. Ptolemy's geocentric theory held back astronomy for nearly 1,500 years. I’ve got an 1860s book in which Thomas Huxley claimed the galaxies were new solar systems being formed. Herschel thought people could live on the sun if they got below the hot atmosphere. I was taught in science classes and in astronomy books in the 1950s that there were green plants growing all over the surface of Mars. The astronomers told Einstein that all the stars and nebula were “fixed” in space. The old “universal ether” theory turned out to be wrong.

rwald
2004-Jan-29, 01:59 AM
Wait, you're saying that science is not about creating a series of models that come closer and closer to accurately predicting the results of future experiments? If you don't understand that basic fact, I think I see why we're having a communication problem.

Chip
2004-Jan-29, 02:02 AM
...I was taught in science classes and in astronomy books in the 1950s that there were green plants growing all over the surface of Mars.

I was told that their might be plants producing the seasonal color changes, but that it wasn't likely. I must have had a more thoughtful teacher. :wink:


...The old “universal ether” theory turned out to be wrong.

Well I'm glad you finally realized that. :wink:

Sam5
2004-Jan-29, 02:56 AM
...I was taught in science classes and in astronomy books in the 1950s that there were green plants growing all over the surface of Mars.

I was told that their might be plants producing the seasonal color changes, but that it wasn't likely. I must have had a more thoughtful teacher. :wink:


...The old “universal ether” theory turned out to be wrong.

Well I'm glad you finally realized that. :wink:

You know what caused that “green plant” illusion?? It was an optical color illusion. Dark green is basically the negative of red-orange, and that caused the darker areas of Mars to look “dark greenish” through earth-based telescopes. I saw it with a 6 inch telescope during the close approach of Mars back in ’56.

At different times of the year the dust storms would start up and cause more greenish or less greenish areas (more darker areas or less darker areas). So some science writers within the science and mass media, who got the information about the “possibility” of plants from astronomers, exaggerated it into “vast fields of green leafy plants that thrived in the warm Martian summer time”, and baloney like that.

By the time I came along. Lowell’s hallucinations about the “canals” had all died out. But back in the 1920s major newspapers were running articles about astronomers receiving “radio messages from Mars”.

Regarding the “ether”, it’s “local”, not “universal”. And in the future, Einstein will be credited with “discovering it”, since it is in his 1911 paper in the form of local gravity fields. Lorentz came so close to discovering it. Dr. Su will probably receive the initial credit, and then later the credit will be given to Einstein.

Diamond
2004-Jan-29, 10:13 AM
...I was taught in science classes and in astronomy books in the 1950s that there were green plants growing all over the surface of Mars.

I was told that their might be plants producing the seasonal color changes, but that it wasn't likely. I must have had a more thoughtful teacher. :wink:


...The old “universal ether” theory turned out to be wrong.

Well I'm glad you finally realized that. :wink:

Regarding the “ether”, it’s “local”, not “universal”. And in the future, Einstein will be credited with “discovering it”, since it is in his 1911 paper in the form of local gravity fields. Lorentz came so close to discovering it. Dr. Su will probably receive the initial credit, and then later the credit will be given to Einstein.

The ether does not exist. It is not the local gravity field. Clocks are not time. You are a crackpot.

milli360
2004-Jan-29, 11:40 AM
Wait, you're saying that science is not about creating a series of models that come closer and closer to accurately predicting the results of future experiments? If you don't understand that basic fact, I think I see why we're having a communication problem.
No, I don't think he is saying that. I agree with Sam5 here, and disagree with what freddo said: "Well we know that the new theories are not developed because the original ones are actually wrong." They were wrong. However, I'm sure that what freddo meant was that the original ones weren't totally wrong, in all aspects. Newton's mechanics are a good example--we still use them today. They're not inconsistent, if applied appropriately.

But Newton's mechanics is wrong--as it stands now, it's only an approximation to GR.

In the same way, I also disagree with Sam5: "If it was not inconsistent, he would not have had to add the gravity field in 1918." That doesn't necessarily follow.


Maybe 100. Maybe 200. I'm glad you were right about something. Why do you suppose the two English versions mistranslate that word?
I remember it as much fewer, but still too many. :) As I remember it, I also gave a bunch of quotations from textbooks that showed that the word "velocity" has historically been used sometimes to indicate "speed" rather than a vector, so it's not a mistranslation so much as our technical language has evolved over the past hundred years.

What do you mean "treated"?
That's what I was referring to when I said "Actually, in his original 1905 paper, Einstein did apply it to a situation where there are accelerations--" Your response to that was "No, you are making that up." I didn't make it up, that one example where he applies his theory to a closed curve is just such a situation.

Sam5
2004-Jan-29, 04:06 PM
What do you mean "treated"?
That's what I was referring to when I said "Actually, in his original 1905 paper, Einstein did apply it to a situation where there are accelerations--" Your response to that was "No, you are making that up." I didn't make it up, that one example where he applies his theory to a closed curve is just such a situation.

Well, he just disregarded the effects of any “accelerations”, just as Pauli said he disregarded the accelerations of the turn-arounds in the clock paradox thought experiments. So he didn’t really “apply” his 1905 theory to any “accelerations”. Accelerations turn up in his turn-around and in his closed curve, but he doesn’t “apply” their forces in any way in the paper.

It’s very common for people to leave out certain laws of physics in thought experiments. Such as if we say, “Ok, we travel to Mars instantly.” Well, that leaves out a lot of laws of physics, but if we are trying to prove a certain point that is not related to acceleration or speed, then that’s ok. But in real life, we certainly must consider acceleration and speed. So his theory contained interesting thought experiments, but they did not apply to real life situations.

He had to add the gravity field later because he finally realized that “relative motion” does nothing to clocks, unless the clocks feel some kind of “force” during their motion.

Do you have a copy of the English translation of the 1918 paper?

Sam5
2004-Jan-29, 04:21 PM
Wait, you're saying that science is not about creating a series of models that come closer and closer to accurately predicting the results of future experiments? If you don't understand that basic fact, I think I see why we're having a communication problem.
No, I don't think he is saying that. I agree with Sam5 here, and disagree with what freddo said: "Well we know that the new theories are not developed because the original ones are actually wrong." They were wrong.

:D


You know, you could be the first guy on the internet to present a true solution – Einstein’s own solution – to the “twins paradox”. All you have to do is say that the 1905 paper contained errors and one error was that it had no “force” applied to the “moving” clocks. Einstein realized that later and added a “gravitational field” and a gravity force to the k frame clocks.

With your website, you would save millions of teenagers countless nights of misery and confusion as they try to figure out what is actually wrong with the original “twins paradox” thought experiments.

But, of course, you would become hated all across America by hundreds of physics professors who have been wrong all their lives and who will continue to claim that their wrong solution is “right”.

Are you a brave man? Are you willing to tell the truth for the sake of Science, Truth, and Justice in the world? Are you willing to have your website turn up on “crackpot” lists all over the internet, even though you would be right and you will be telling the Truth?

If you do decide to make that change, I’ll defend you and I’ll try to get the other websites to take you off their “crackpot” lists. Remember, this is Honesty in the name of Science, Liberty, and the Freedom of Mankind, and a bold step forward in the Freedom of Thought and of Speech, and of Truth and of Honesty in Science.

milli360
2004-Jan-29, 05:08 PM
You know, you could be the first guy on the internet to present a true solution – Einstein’s own solution – to the “twins paradox”. All you have to do is say that the 1905 paper contained errors and one error was that it had no “force” applied to the “moving” clocks. Einstein realized that later and added a “gravitational field” and a gravity force to the k frame clocks.
We're not that far apart, you and I. I have come to a different conclusion about Einstein's motives, though. It is hard to discern another person's motives, with any certainty, even if the other person has left testimony behind. The testimony could be false.

The reason that I don't see Einstein's work in the "peculiar consequence" as a mistake, or a misstep, is because I would have done the same thing, even knowing what I know now. How do I know I would have done it the same way? Because I did. I wrote those webpages with my explanation of the twin paradox (http://mentock.home.mindspring.com/twins.htm) before I'd studied Einstein's 1905 paper. I was surprised, and pleased, to see that the method I used was the same method Einstein used when he first introduced the "twin paradox" (although he did not call it that then), almost a hundred years ago.

So, I'm going to persist in thinking that that was not a mistake on his part, not just because I did it too, but because I am still convinced that it is a reasonable thing to do.

Are you a brave man? Are you willing to tell the truth for the sake of Science, Truth, and Justice in the world?
Sure. Somehow it doesn't seem that hard. Ten years ago, I discovered that the entire geophysical community was ignoring a fundamental aspect of the Earth's interior. When I talked to the researchers whose papers I criticized, I did not receive any recriminations. One, a leading geophysicist at MIT, agreed to serve on my committee. Another, the discover of plate tectonics, agreed to read over some preprints, and offered me some very helpful advice. When I talked to Subrahmanyan Chandrasekhar, the Nobel prize winner after whom the x-ray telescope is named, he agreed with me, and explained that he'd boxed up all his work in 1960 and had ignored the field for almost forty years--he said he'd had no idea that the geophysicists had mischaracterized his work.

Are you willing to have your website turn up on “crackpot” lists all over the internet, even though you would be right and you will be telling the Truth?
The reason it doesn't seem that hard, is because when I've put up info like that, I don't seem to appear on crackpot lists. A few folk list me on their websites, as a reference, but that's about it. It's not that difficult. All you have to do is do your homework.


If you do decide to make that change, I’ll defend you and I’ll try to get the other websites to take you off their “crackpot” lists. Remember, this is Honesty in the name of Science, Liberty, and the Freedom of Mankind, and a bold step forward in the Freedom of Thought and of Speech, and of Truth and of Honesty in Science.
We'll see about that. How committed are you?

Sam5
2004-Jan-29, 05:28 PM
We're not that far apart, you and I. I have come to a different conclusion about Einstein's motives, though. It is hard to discern another person's motives, with any certainty, even if the other person has left testimony behind. The testimony could be false.

Look, I’ve become an expert at investigating “motives”. If I can’t figure out a guy’s motive, I usually just drop the investigation. Understanding the motive is one of the most important things when conducting an historical investigation.

My ability comes from many years of concentrating on single investigations for decades, and from reading all I can about what the subject of the investigation read and experienced during his lifetime.

I now know why Einstein was so vague about the changes and updates in his overall theory as time went by. It took me years to figure it out, but I’ve at last obtained enough information about it to be able to say why he was so vague. I noticed his vagueness long before I found out why he was being vague. At first, I thought he was just refusing to admit a mistake, but I later found out there was much more to it than that.



The reason that I don't see Einstein's work in the "peculiar consequence" as a mistake, or a misstep, is because I would have done the same thing, even knowing what I know now. How do I know I would have done it the same way? Because I did. I wrote those webpages with my explanation of the twin paradox (http://mentock.home.mindspring.com/twins.htm) before I'd studied Einstein's 1905 paper. I was surprised, and pleased, to see that the method I used was the same method Einstein used when he first introduced the "twin paradox" (although he did not call it that then), almost a hundred years ago.

Yes, but – please don’t take offence – but your webpages are filled with errors too. That’s because you based them on erroneous information, on other “solutions” of the twins paradox that were not correct. You’ve incorporated some of his own original errors into your “solutions”, plus you’ve added even more errors of your own.




So, I'm going to persist in thinking that that was not a mistake on his part, not just because I did it too, but because I am still convinced that it is a reasonable thing to do.

milli360
2004-Jan-29, 05:51 PM
Look, I’ve become an expert at investigating “motives”. If I can’t figure out a guy’s motive, I usually just drop the investigation. Understanding the motive is one of the most important things when conducting an historical investigation.

My ability comes from many years of concentrating on single investigations for decades, and from reading all I can about what the subject of the investigation read and experienced during his lifetime.
I respect that, but, respectfully, you have missed half of what is available, just because of the inability to understand the math. I'm sorry, but every objection that you've ever raised seems to have been based upon a misunderstanding of the math involved.

That's why everybody delights in jumping upon your latest math faux pas--and how many exchanged did it take before you understood what we were trying to say about "cdt". That wasn't our fault, that was just an inability to read math.


I now know why Einstein was so vague about the changes and updates in his overall theory as time went by. It took me years to figure it out, but I’ve at last obtained enough information about it to be able to say why he was so vague.
You've ignored half of the info available. Not purposely, I'm sure.


I noticed his vagueness long before I found out why he was being vague. At first, I thought he was just refusing to admit a mistake, but I later found out there was much more to it than that.
No matter what his motives were, I haven't yet been convinced that that is a mistake. It seems fine to me.


Yes, but – please don’t take offence – but your webpages are filled with errors too. That’s because you based them on erroneous information, on other “solutions” of the twins paradox that were not correct. You’ve incorporated some of his own original errors into your “solutions”, plus you’ve added even more errors of your own.

I'm satisfied with them as they are. I think you may have to hire a math translator. Maybe the government will furnish you one for free. :)

Sam5
2004-Jan-29, 05:56 PM
So, I'm going to persist in thinking that that was not a mistake on his part, not just because I did it too, but because I am still convinced that it is a reasonable thing to do.


But there is a simpler and more correct solution to the “twins paradox” than the incorrect "solutions" on your websites: He simply made mistakes in the 1905 paper, he realized the errors by 1911, and he corrected them by 1918.





Ten years ago, I discovered that the entire geophysical community was ignoring a fundamental aspect of the Earth's interior. When I talked to the researchers whose papers I criticized, I did not receive any recriminations. One, a leading geophysicist at MIT, agreed to serve on my committee. Another, the discover of plate tectonics, agreed to read over some preprints, and offered me some very helpful advice. When I talked to Subrahmanyan Chandrasekhar, the Nobel prize winner after whom the x-ray telescope is named, he agreed with me, and explained that he'd boxed up all his work in 1960 and had ignored the field for almost forty years--he said he'd had no idea that the geophysicists had mischaracterized his work.

Good for you. I’ve had a couple of Nobel Prize winners agree with me about a different issue. I was referenced 4 times in three different articles in the JAMA back in the early 1990s because of my discovery involving the forensics investigation of a certain case. I’ve received AP journalism awards for my investigations.



We'll see about that. How committed are you?

I’m committed enough to allow myself to be yelled at, called nasty names, and be ridiculed for the past 4 years on the internet.

It would have been one heck of a lot easier for me if I had just gone along with the popular opinion about this. I could have been an international “hero” and quoted around the world if I had, like everybody else, posted incorrect “solutions” to the “twins paradox” on the internet, but I refused to do it.

milli360
2004-Jan-29, 06:02 PM
But there is a simpler and more correct solution to the “twins paradox” than the incorrect "solutions" on your websites: He simply made mistakes in the 1905 paper, he realized the errors by 1911, and he corrected them by 1918.
You've said before that it has to do with the force "felt" by the clocks, but we've discussed that--the potential box thought experiment shows that your theory is incorrect somewhere. It's not as simple as you think.


I’m committed enough to allow myself to be yelled at, called nasty names, and be ridiculed for the past 4 years on the internet.

I'm sure you gave as good as you got. :)


It would have been one heck of a lot easier for me if I had just gone along with the popular opinion about this. I could have been an international “hero” and quoted around the world if I had, like everybody else, posted incorrect “solutions” to the “twins paradox” on the internet, but I refused to do it.
You mean, like me? :)

When does my international hero certificate arrive?

Sam5
2004-Jan-29, 06:21 PM
But there is a simpler and more correct solution to the “twins paradox” than the incorrect "solutions" on your websites: He simply made mistakes in the 1905 paper, he realized the errors by 1911, and he corrected them by 1918.
You've said before that it has to do with the force "felt" by the clocks, but we've discussed that--the potential box thought experiment shows that your theory is incorrect somewhere. It's not as simple as you think.


No. In the first place, I don’t think he ever talked about “potential” in terms of an accelerating moving box. The “potential” term is related to gravity, because the potential changes at greater distances from the center of a mass (at greater distances from the bottom of the box resting in a gravity field). But the forces felt inside the moving box are the same everywhere in the box. Whenever the acceleration rate of the moving box changes, the forces felt at all places inside the box change in exactly the same amount. But there is no difference in forces anywhere inside the moving box.

Also, remember that his “box” thought experiments were in his 1911 paper and he was dealing with electrodynamical effects inside an atom. Apparently, the slightest gravitational potential changes can alter the internal vibration rate of an atom.

In an accelerating box in deep space, all the atoms’ vibration rates slow down the same amount inside the box. But in a box at the earth, the vibration rates slow down more the closer the atoms are to the bottom of the box.

And his 1911 equations and effects don’t necessarily affect mechanical clocks the same way. In fact, gravity affects a pendulum clock in exactly the opposite way, speeding it up in stronger gravity.

milli360
2004-Jan-29, 06:37 PM
The “potential” term is related to gravity, because the potential changes at greater distances from the center of a mass (at greater distances from the bottom of the box resting in a gravity field).

For the most part, true. What that means is, if someone were to climb a ladder, the energy they expend would be transformed into potential energy. So, they gain potential energy as they climb. If they were to fall, they'd lose the potential energy, but gain kinetic energy as their velocity increased.


But the forces felt inside the moving box are the same everywhere in the box.
I'll grant that.

Whenever the acceleration rate of the moving box changes, the forces felt at all places inside the box change in exactly the same amount. But there is no difference in forces anywhere inside the moving box.
I'll grant that also. But that means that the top of the box is at a different potential than the bottom. Someone at the bottom would have to expend energy to climb up a ladder to the top of the box.


In an accelerating box in deep space, all the atoms’ vibration rates slow down the same amount inside the box. But in a box at the earth, the vibration rates slow down more the closer the atoms are to the bottom of the box.
Not according to GR. That's why your "solution" is wrong.

Your first clue should have been the equivalence of gravity and acceleration, in general relativity. That's key.

SeanF
2004-Jan-29, 07:13 PM
In an accelerating box in deep space, all the atoms’ vibration rates slow down the same amount inside the box. But in a box at the earth, the vibration rates slow down more the closer the atoms are to the bottom of the box.

In Einstein's 1911 paper, the equation E1=E2(1+yh/c^2) refers to two clocks at different "heights" (distance of h) in a system accelerating at rate y, and it leads directly (through the equivalence principle) to E1=E2(1+Φ/c^2), where Φ is the difference in gravitational potential.

You're wrong when you say that his 1911 paper suggests clocks at different heights in an accelerating box are affected equally.

Sam5
2004-Jan-29, 10:06 PM
You're wrong when you say that his 1911 paper suggests clocks at different heights in an accelerating box are affected equally.

No I’m not.

It all depends on whether you are “accelerating” the box by means of motion or by means of a gravity field.

You need to get the book with the full article. The website version of the article leaves out some stuff. It leaves out about a page.

Here’s the thing that he says in the 1911 paper that so many people seem to miss:

1) Atomic clock tick rates slow down in a gravity field.

2) The speed of light slows down in a gravity field.

Most people get the stuff about the atomic clock tick rates, since it is repeated so often, but they miss the stuff about the light speed slowing down.

Also, in a moving box, if we rest atomic clocks at different places inside the box, all the clocks will tick at the same rate, since the acceleration is evenly being transmitted up from the floor of the box, through the walls, to all resting positions inside the box.

But, if we rest the box inside a gravity field, each different elevation inside the box will cause atomic clocks to tick at faster rates, the farther they are from the floor of the box. This is why the “equivalence principle” breaks down under certain conditions.

Now, if you take each clock elevation-position inside the resting box, and you transfer that to the moving box by using multiple moving boxes, and by having each moving box experience a different acceleration rate, based on the different g forces felt inside the resting box at the different elevations, then the clocks inside the different moving boxes will tick at different rates. But every clock inside each individual moving box will tick at the same rate.

Sam5
2004-Jan-29, 10:12 PM
Your first clue should have been the equivalence of gravity and acceleration, in general relativity. That's key.


It is “equivalent” only if the g force is exactly the same in every place inside the box, such as at the floor of the box.

On earth, the g force is 1 g on the floor. But higher up in the box it is less than 1 g.

In a moving box, the g force on the floor would be 1 g, and so would the g force be 1 g at a resting place higher up in the box.

milli360
2004-Jan-29, 10:21 PM
Also, in a moving box, if we rest atomic clocks at different places inside the box, all the clocks will tick at the same rate, since the acceleration is evenly being transmitted up from the floor of the box, through the walls, to all resting positions inside the box.
You're missing the point of what SeanF and I are trying to say.

That is true only in your version of the theory. According to GR, that is not true.

That's why I've repeated that the potential box experiment shows why your version is wrong--if you believe that GR is right.

SeanF
2004-Jan-29, 10:27 PM
Also, in a moving box, if we rest atomic clocks at different places inside the box, all the clocks will tick at the same rate, since the acceleration is evenly being transmitted up from the floor of the box, through the walls, to all resting positions inside the box.

No. As I pointed out, the equation E1=E2(1+yh/c^2) comes from this exact situation. The situation you described is exactly how Einstein comes up with the equation at the beginning of the 1911 paper. Would you like me to step you through it?

Sam5
2004-Jan-30, 12:00 AM
No. As I pointed out, the equation E1=E2(1+yh/c^2) comes from this exact situation. The situation you described is exactly how Einstein comes up with the equation at the beginning of the 1911 paper.

At the beginning of the paper he was talking about a homogeneous gravitational field.

The moving box is like it has a “homogeneous gravitational field”.

Geez!

freddo
2004-Jan-30, 12:09 AM
disagree with what freddo said: "Well we know that the new theories are not developed because the original ones are actually wrong." They were wrong. However, I'm sure that what freddo meant was that the original ones weren't totally wrong, in all aspects. Newton's mechanics are a good example--we still use them today. They're not inconsistent, if applied appropriately.

I disagree with my wording too, but you've deconstructed the gist of my argument perfectly. Cheers.


At the beginning of the paper he was talking about a homogeneous gravitational field.

The moving box is like it has a “homogeneous gravitational field”.

The math 'says' more than the words.

Normandy6644
2004-Jan-30, 01:34 AM
The math 'says' more than the words.

We've been trying to say this for so long, though something tells me it's not sinking in...

Sam5
2004-Jan-30, 01:47 AM
disagree with what freddo said: "Well we know that the new theories are not developed because the original ones are actually wrong." They were wrong. However, I'm sure that what freddo meant was that the original ones weren't totally wrong, in all aspects. Newton's mechanics are a good example--we still use them today. They're not inconsistent, if applied appropriately.

I disagree with my wording too, but you've deconstructed the gist of my argument perfectly. Cheers.


At the beginning of the paper he was talking about a homogeneous gravitational field.

The moving box is like it has a “homogeneous gravitational field”.

The math 'says' more than the words.


I didn’t think you would know what a “homogeneous gravitational field” is.

Sam5
2004-Jan-30, 01:49 AM
The math 'says' more than the words.

We've been trying to say this for so long, though something tells me it's not sinking in...

No wonder you guys don't realize Einstein said light slows down in a gravity field.

Normandy6644
2004-Jan-30, 01:58 AM
The math 'says' more than the words.

We've been trying to say this for so long, though something tells me it's not sinking in...

No wonder you guys don't realize Einstein said light slows down in a gravity field.

Sam, what are you talking about? I already admitted that light slows down in a gravitational field. What I said was that it will not travel faster than c. It is fastest (c) in a vacuum and slowest (0) in a singularity. What's hard to understand? And what does this have to do with the math being more important than the words?

Sam5
2004-Jan-30, 02:10 AM
Sam, what are you talking about? I already admitted that light slows down in a gravitational field. What I said was that it will not travel faster than c. It is fastest (c) in a vacuum and slowest (0) in a singularity.


So, then, you would say that the speed of light is variable as it travels around space, with the max speed of c in deep space, and slower speeds when it passes near the earth and the sun?

SeanF
2004-Jan-30, 02:27 AM
No. As I pointed out, the equation E1=E2(1+yh/c^2) comes from this exact situation. The situation you described is exactly how Einstein comes up with the equation at the beginning of the 1911 paper.

At the beginning of the paper he was talking about a homogeneous gravitational field.

He was comparing a homogenous gravitational field to an accelerating frame, yes.


The moving box is like it has a “homogeneous gravitational field”.

Absolutely. That's why the equation E1=E2(1+yh/c^2) is valid for an accelerating frame or a homogenous gravitational field.


Geez!

Indeed. The two clocks at different heights in the accelerating box are affected differently, just like in a homogenous gravitational field. Which is what I said.

Normandy6644
2004-Jan-30, 02:29 AM
Sam, what are you talking about? I already admitted that light slows down in a gravitational field. What I said was that it will not travel faster than c. It is fastest (c) in a vacuum and slowest (0) in a singularity.


So, then, you would say that the speed of light is variable as it travels around space, with the max speed of c in deep space, and slower speeds when it passes near the earth and the sun?

I think (based on a relatively - ha - understanding of this particular GR phenomenon) that that is correct, though I think that the actual change in velocity is small except for very large masses.

lolife
2004-Feb-01, 07:02 AM
All electromagnetic waves travel at the same speed through a vacuum, a value somthing around 300,000 km / s. Einstein says in his theory of relativity that the speed of light is always the same, no matter how fast its source is traveling. Speed of an electromag. wave is just freq. times wavelength. Given this, how is Red Shift possible? Even if the source of light is traveling away from us, the light is still traveling at a constant speed. Does the freq. change as well? Thank you

Fascinating thread.

Getting back to the original question the redshift occurs due to relative motion between the source and the observer. It matters not whether this is from proper motion, spacetime expansion or because you have a nice new Starship Enterprise. If either the source or the reciever or both moves, the frequency and wavelength of the light changes. This is not a phenomena unique to light -- all waves do this.

You can think of the wavelength as the actual length between wavecrests and the frequency as how many of these wavecrests go past you in a given amount of time. When a star is receding, the wavelengh is longer because the source moved between wavecrests. Thus, the frequency is lower because at the fixed velocity of light, longer wavelengths mean less go by you in a given time. The reverse is true if you have Data fly the Enterprise towards the star -- the wavelength seems shorter (although it is not) because you are passing wavecrests faster. Thus when the source moves, the wavelength actually changes and when the reciever moves it just seems to change.

Are you hardcore GR freaks trying to tell us that there is such a thing as gravity-induced redshift? Just off the top of my head, I think if c is reduced f would be reduced but lambda would be unaffected. The length between wavecrests would be the same but they would go by you slower. Presuming light resumed its normal speed after passing by the ungodly massive gravitational body, there would not be such a thing as gravity-induced redshift.

Michael

Taibak
2004-Feb-01, 02:56 PM
Are you hardcore GR freaks trying to tell us that there is such a thing as gravity-induced redshift? Just off the top of my head, I think if c is reduced f would be reduced but lambda would be unaffected. The length between wavecrests would be the same but they would go by you slower. Presuming light resumed its normal speed after passing by the ungodly massive gravitational body, there would not be such a thing as gravity-induced redshift.

Michael

Yup - Gravitational redshift exists. As I understand the equations, the speed of light is invariant in a gravitational field. According to general relativity, light *always* travels along a null geodesic (the shortest possible path through curved spacetime) at a speed of c. However, the light is affected by gravity - the curvature of spacetime causes its frequency to decrease and its wavelength to increase.

Probably the easiest way to think of this is in terms of energy conservation. As light moves away from a gravitational source, it gains gravitational potential energy. Since its speed is constant, its kinetic energy can't change. Therefore, because E = hf, its *frequency* must decrease to lower its energy. Since its frequency is decreasing and its speed is constant, the light's wavelength (c = lamda*f) must increase. This phenomenon has been observed in both terrestrial experiments and in the spectra of white dwarfs.

Sam5
2004-Feb-01, 05:19 PM
Are you hardcore GR freaks trying to tell us that there is such a thing as gravity-induced redshift? Just off the top of my head, I think if c is reduced f would be reduced but lambda would be unaffected. The length between wavecrests would be the same but they would go by you slower. Presuming light resumed its normal speed after passing by the ungodly massive gravitational body, there would not be such a thing as gravity-induced redshift.

Michael

If light is emitted from a massive body, the first thing that happens is a redshift in the light as it is emitted. That is because the internal oscillation rates of the atoms is slowed down by the gravity field, and that reduces the frequency of the light that that they emit.

The second thing that happens is that the light first moves slowly away from the emitting body. As the light gets further away from the body, it gains speed. This stretches the wavelengths and causes a second redshift.

On the other hand, when normal-speed light passes through a gravity field, it acts like it is passing through water or glass. The speed slows down, the wavelengths bunch up, and a time lag develops. Slow light and bunched up waves do not produce a redshift or a blueshift. As the light leaves the gravity field, the speed increases and the waves un-bunch and return to their normal length. The overall effect is neither a blueshift or a redshift, but a time lag, a delay in the light. So the light is eventually seen as being the normal frequency and wavelength, but its arrival is slightly time-lagged. This is what happens when radar signals are sent past the sun and bounce back off of distant planets. The signals are time-lagged but not red or blue shifted.

Taibak
2004-Feb-01, 05:43 PM
Are you hardcore GR freaks trying to tell us that there is such a thing as gravity-induced redshift? Just off the top of my head, I think if c is reduced f would be reduced but lambda would be unaffected. The length between wavecrests would be the same but they would go by you slower. Presuming light resumed its normal speed after passing by the ungodly massive gravitational body, there would not be such a thing as gravity-induced redshift.

Michael

If light is emitted from a massive body, the first thing that happens is a redshift in the light as it is emitted. That is because the internal oscillation rates of the atoms is slowed down by the gravity field, and that reduces the frequency of the light that that they emit.

Not to be too pedantic, but keep in mind that this is *only* true when the light is observed by a distant observer. If you were to shine a flashlight in my face, and we're at rest relative to each other, after my swearing had died down I would see the same frequency light that the flashlight does, because time is passing at the same rate for us. If you were to shine the flashlight at Mars, any martians who see it would see a slight redshift.


The second thing that happens is that the light first moves slowly away from the emitting body. As the light gets further away from the body, it gains speed. This stretches the wavelengths and causes a second redshift.

I don't think so. For starters, I'm still unconvinced that the speed of light changes in the presence of gravity. Time and space change, but c is constant. The math seems funky as well. Since v = wf (where w = wavelength and f = frequency), if v increases and w increases proportionally, then f *must* remain unchanged. That doesn't seem to make physical sense. A change in wavelength means a change in color - but a constant frequency means no change in color. That simply doesn't make any sense. Similarly, what about the light's energy? A change in speed means a change in kinetic energy. However, the kinetic energy of light is given by E = hf. Since f is not changing, E *can't* change.

In other words, if the wavelength and speed of light are variables affected by gravity, then the frequency of light must be constant. However, if the frequency was constant, the light's energy won't change (which it must if c changes) and no redshift will be observed. Since we observe a redshift, f *must* change proportional to c. Therefore, the speed of light, c, *MUST* be invariable, regardless of gravity.


On the other hand, when normal-speed light passes through a gravity field, it acts like it is passing through water or glass. The speed slows down, the wavelengths bunch up, and a time lag develops. Slow light and bunched up waves do not produce a redshift or a blueshift. As the light leaves the gravity field, the speed increases and the waves un-bunch and return to their normal length. The overall effect is neither a blueshift or a redshift, but a time lag, a delay in the light. So the light is eventually seen as being the normal frequency and wavelength, but its arrival is slightly time-lagged. This is what happens when radar signals are sent past the sun and bounce back off of distant planets. The signals are time-lagged but not red or blue shifted.

Um, no it doesn't. Light is slowed down when it enters a medium because the photons are being constantly absorbed and re-emitted by the atoms in the glass, air, water, or what have you. Gravity has no such effect. You're right that those redshifts and blueshifts take place, but that, as I argued above, has nothing to do with the light changing speed. It's strictly a question of warped spacetime changing the light's energy.

Sam5
2004-Feb-01, 06:07 PM
Not to be too pedantic, but keep in mind that this is *only* true when the light is observed by a distant observer. If you were to shine a flashlight in my face, and we're at rest relative to each other, after my swearing had died down I would see the same frequency light that the flashlight does, because time is passing at the same rate for us. If you were to shine the flashlight at Mars, any martians who see it would see a slight redshift.


Ok, I'll go along with that.


For starters, I'm still unconvinced that the speed of light changes in the presence of gravity. Time and space change, but c is constant. The math seems funky as well. Since v = wf (where w = wavelength and f = frequency), if v increases and w increases proportionally, then f *must* remain unchanged. That doesn't seem to make physical sense. A change in wavelength means a change in color - but a constant frequency means no change in color. That simply doesn't make any sense. Similarly, what about the light's energy? A change in speed means a change in kinetic energy. However, the kinetic energy of light is given by E = hf. Since f is not changing, E *can't* change.

In other words, if the wavelength and speed of light are variables affected by gravity, then the frequency of light must be constant. However, if the frequency was constant, the light's energy won't change (which it must if c changes) and no redshift will be observed. Since we observe a redshift, f *must* change proportional to c. Therefore, the speed of light, c, *MUST* be invariable, regardless of gravity.

Hmm, I think what you say suggests that the light is not redshifted a second time. The wavelengths are stretched out, but that does not lead to a redshift, since it is caused by a speed change. It is emitted redshifted to start with, because the oscillation rates of the atoms are slower. The light starts out moving slow but it gradually speeds up. This would not change the frequency again, but would merely stretch out the waves.

What do you think about this? Let’s use a single earth clock to measure both the frequency and the speed in both places:




light emitted light received
in strong gravity: in weak gravity:
slow speed: fast speed:
emitted observed
frequency frequency
10 10

0.... . . . . . . . . . . . . . . . . . > o

lolife
2004-Feb-01, 06:10 PM
Thanks for the info. I read ahead in my quantum mechanics book a bit and there is a section called "The Gravitational Redshift". Doh.

From my reading of it, the principle of equivalence means that the light is affected as if the source and detector were accelerating, so for fixed c there is an apparant shift based on the motion of the detector. Thus light "falling" towards a body is blueshifted and light rising from a body is redshifted.

Sam5
2004-Feb-01, 06:26 PM
Thanks for the info. I read ahead in my quantum mechanics book a bit and there is a section called "The Gravitational Redshift". Doh.

From my reading of it, the principle of equivalence means that the light is affected as if the source and detector were accelerating, so for fixed c there is an apparant shift based on the motion of the detector. Thus light "falling" towards a body is blueshifted and light rising from a body is redshifted.


I think I was probably wrong about that “2nd redshift” as the light leaves a massive body. What I think it is, is a photon speed up which causes a wavelength shift but not a second redshift.

I think some physicists like to make “c” a constant and just change the frequency and the wavelength. But I prefer to change whatever needs to be changed.

If gravity slows down light speed in nature, then that’s ok.

If the observer is moving toward the emitter, such as the earth moving toward a star that is fixed with the sun, the earth will see a blueshift. I think this is because the star light waves in deep space will be about “c”, and the earth is moving toward them, so the combined rate is c + v. The blueshift is due to a relative light-speed change.

However, using Dr. Su’s “local ether” theory, as the waves encounter the earth’s gravity field, they slow down. They can’t pass through the earth’s gravity field at c + v. They will be regulated to a local “c” speed at the earth by the earth’s local gravity field. This slowdown is what physically causes the waves to “bunch up”. That’s where the blueshift actually takes place, at the earth, within its own local gravity field. So, we see blueshifted light from the star we are moving toward. Also, our local measurement of “c” depends on the local tick-rate of our local atomic clocks. And that rate slows down in a stronger gravity field. So does the light speed slow down in a stronger field.

So, someone with an atomic clock on a mountain top should measure blueshifted star light moving at “c” on the mountain, and someone at sea level should measure the same amount of blueshifted star light moving at “c” at sea level, with the same speed measurement based on the two different tick rates of the two atomic clocks.

I think I got that one right. Let me know if you see an error.

Sam5
2004-Feb-01, 06:42 PM
lolife,

Let me see if I can get this one right......

Think of light passing through a gravity field being something like light passing through glass. The light slows down in glass, and the light slows down in a gravity field.

If 10 waves enter the glass at c, they pass through the glass at less than c and they are bunched up. But, they are moving slower, so the bunch-up does not produce a blueshift. When the waves begin to exit the glass, they speed up again and their waves stretch out again to the normal wavelength. All that has happened to the light photons, as far as the observer is concerned, is that they experienced a slight time lag while they were traveling at the slow speed through the glass.

So, we’ve got several things going on with gravitational and motion-related red and blueshifts.

We’ve got the lower frequency of light being emitted by a slowly oscillating atom. We’ve got light speed changing as it leaves a gravity field.

With motion of the observer toward a source, we’ve got the c + v phenomenon, and with the observer moving away from the source, we’ve got the c – v phenomenon. However, at the observer, who is resting on a planet, the planet’s local gravity field controls the local speed of the light to "c".

As the c + v light slows down in that local gravity field, the waves bunch up, producing a blueshift. As the c – v light enters the local gravity field, it speeds up, producing a redshift. With the observer/earth moving, the shifts take place at the earth. With the source moving relative to the sun, the shifts take place at or closer to the source. With the gravity fields in deep space regulating the speed of light in deep space.

I think these speed changes are probably very slight within our galaxy, but they are much greater on the large astronomical scale.

Sam5
2004-Feb-01, 07:02 PM
Taibak, lolife,

Regarding Dr. Su’s “local ether” theory, Einstein hinted at this type of idea in one of his 1918 papers, when he said:

“There [in the GR theory], empty space in the previous sense has physical qualities, mathematically characterized by the components of the potential of gravitation that determine the metrical behavior of that portion of space as well as its gravitational field. This situation can very well be interpreted by speaking of an ether whose state varies from point to point.”

The flaw in Einstein’s ideas that prevented him from discovering the “local ether” theory himself was that he did not acknowledge this “gravitational ether” as moving “through” space with astronomical bodies.

Dr. Su does realize that the "gravitational ether" does move through space with astronomical bodies, and, thus, it regulates the local speed of light at the bodies.

milli360
2004-Feb-01, 07:07 PM
Um, no it doesn't. Light is slowed down when it enters a medium because the photons are being constantly absorbed and re-emitted by the atoms in the glass, air, water, or what have you.
Depends upon what you mean by obsorbed and reemitted. Is a photon that travels through a transparent medium like glass absorbed? How does it travel straight through then?

Sam5
2004-Feb-01, 07:13 PM
Um, no it doesn't. Light is slowed down when it enters a medium because the photons are being constantly absorbed and re-emitted by the atoms in the glass, air, water, or what have you.
Depends upon what you mean by obsorbed and reemitted. Is a photon that travels through a transparent medium like glass absorbed? How does it travel straight through then?


Good question. Looks to me like it is just slowed down during its trip through the glass. Seems to me like absorption and re-emission would scatter light beams all over the place, instead of sending them out in the same straight direct line in which they entered the glass.

Sam5
2004-Feb-01, 07:17 PM
How does it travel straight through then?

Suppose we say that the atoms of the glass act like “little planets”, and because of their strong fields at close range, those fields slow down the light beam as the beam passes through those fields at close range to the atoms, just as light beams are slowed down as they pass through a gravity field of a big planet.

So, what I see is a slowing of the light speed as it passes directly through glass. Some photons hit glass atoms and are absorbed, so the beam coming out of the glass is not quite as bright as the beam that entered the glass.

lolife
2004-Feb-02, 05:27 PM
Good question. Looks to me like it is just slowed down during its trip through the glass. Seems to me like absorption and re-emission would scatter light beams all over the place, instead of sending them out in the same straight direct line in which they entered the glass.

Except the momentum vectors are all pointed in the same direction. In terms of QED wouldn't this mean that there is a much higher probability that the photons continue in that same direction?

swansont
2004-Feb-02, 06:55 PM
Good question. Looks to me like it is just slowed down during its trip through the glass. Seems to me like absorption and re-emission would scatter light beams all over the place, instead of sending them out in the same straight direct line in which they entered the glass.

Except the momentum vectors are all pointed in the same direction. In terms of QED wouldn't this mean that there is a much higher probability that the photons continue in that same direction?

I think it has to do with the fact that the absorptions and emissions have to do with virtual states (otherwise only discrete frequencies would be slowed, for the real states of the medium). I vaguely recall that you can't transfer energy or momentum in the interaction because of that. Interactions with real states will cause light to be scattered or absorbed.

Recall that this is the particle view - the wave view is that you've changed the permittivity and permeability, and these have a direct effect on wave speed. So you can say the wave slowed down, or you can say that the photons spent some time being absorbed and re-emitted.

Sam5
2004-Feb-02, 07:10 PM
Good question. Looks to me like it is just slowed down during its trip through the glass. Seems to me like absorption and re-emission would scatter light beams all over the place, instead of sending them out in the same straight direct line in which they entered the glass.

Except the momentum vectors are all pointed in the same direction. In terms of QED wouldn't this mean that there is a much higher probability that the photons continue in that same direction?

I don’t know enough about the subject in detail to be able to know for sure. It seems to me that if the photons are absorbed and re-emitted so many times while going through glass, that would cause more of a diffusion or light scattering effect than if the original photons just moved through the glass.

milli360
2004-Feb-02, 07:25 PM
I think it has to do with the fact that the absorptions and emissions have to do with virtual states (otherwise only discrete frequencies would be slowed, for the real states of the medium).
Yes, and that only affects the calculation of where things end up. As you point out, there can be no real absorption. Cute, eh?

Although the mental image of photons shooting through at c, and bouncing around like billiards to slow down, is a tempting one, it doesn't seem to be realistic at all.

swansont
2004-Feb-02, 10:15 PM
I think it has to do with the fact that the absorptions and emissions have to do with virtual states (otherwise only discrete frequencies would be slowed, for the real states of the medium).
Yes, and that only affects the calculation of where things end up. As you point out, there can be no real absorption. Cute, eh?

Although the mental image of photons shooting through at c, and bouncing around like billiards to slow down, is a tempting one, it doesn't seem to be realistic at all.

It's not so much bouncing like billiard balls as it is getting caught at the occasional traffic light, but going "c" the rest of the time. But just when you think it's all a con job, you find that the "virtual states" description actually works for real phenomenon that have no classical explanation, like Raman scattering.

Taibak
2004-Feb-03, 01:03 AM
For starters, I'm still unconvinced that the speed of light changes in the presence of gravity. Time and space change, but c is constant. The math seems funky as well. Since v = wf (where w = wavelength and f = frequency), if v increases and w increases proportionally, then f *must* remain unchanged. That doesn't seem to make physical sense. A change in wavelength means a change in color - but a constant frequency means no change in color. That simply doesn't make any sense. Similarly, what about the light's energy? A change in speed means a change in kinetic energy. However, the kinetic energy of light is given by E = hf. Since f is not changing, E *can't* change.

In other words, if the wavelength and speed of light are variables affected by gravity, then the frequency of light must be constant. However, if the frequency was constant, the light's energy won't change (which it must if c changes) and no redshift will be observed. Since we observe a redshift, f *must* change proportional to c. Therefore, the speed of light, c, *MUST* be invariable, regardless of gravity.

Hmm, I think what you say suggests that the light is not redshifted a second time. The wavelengths are stretched out, but that does not lead to a redshift, since it is caused by a speed change. It is emitted redshifted to start with, because the oscillation rates of the atoms are slower. The light starts out moving slow but it gradually speeds up. This would not change the frequency again, but would merely stretch out the waves.

Sort of. What I'm saying is that the first scenario and the second scenario are essentially the same thing. You only observe the redshift or blueshift when the light changes its gravitational potential energy as it moves.

However, this does not require the light's *speed* to change. Again, it all comes down to a simple measure of energy conservation. You shoot light straight up from the surface of a planet with no atmosphere. Since it's moving away from the Earth's center of gravity, it is *gaining* gravitational potential energy. Since energy must be conserved, the photon, somehow, has to *lose* energy from somewhere. Since we're talking about particles that have no rest mass, K = (mv^2)/2 does not work. You have to use the equation:


E = hf = hc/w,

where w = wavelength, f = frequency, c is the light's speed, E = the light's total energy, and h = Planck's constant.

Think about this: you're arguing that the wave's *frequency* remains constant no matter what. That means that even if c and w change, the light's *energy* will remain constant. If that's the case, it violates the law of conservatin of energy, big time. There is no way the light could lose the energy it needs to compensate for gaining gravitational potential energy.

On the other hand, what happens if the speed of light remains constant? Now, the proportionality works so that E *can* change, but only if both frequency and wavelength change. That's the only way out of this without violating energy conservation.



What do you think about this? Let’s use a single earth clock to measure both the frequency and the speed in both places:




light emitted light received
in strong gravity: in weak gravity:
slow speed: fast speed:
emitted observed
frequency frequency
10 10

0.... . . . . . . . . . . . . . . . . . > o


To be honest, it doesn't work. The same clock can't be used to make both measurements. To do this experiment, the clock has to be at rest relative to the gravity source when the light is emitted. It will also need to be at rest relative to the gravity source when it receives the light. If you use only one clock, you would have to accelerate it past the speed of light and the decelerate it to bring it back to a stop at the point where the light is received. This is impossible because the clock can't be in two places at the same time. You also can't accelerate an object to faster than light speeds - you can't even get it to reach light speed. Even if you could, the amount of time that passes, as measured by the clock, will be directly affected by the clock's motion relative to the gravity source. Similarly, the amount of time that passes is also affected by the gravitational potential experienced by the clock at any given moment. That means even if you have two clocks, one at each point, they'll experience time passing at different rates. Either way, the that difference in the passage of time will lead to two different frequencies and wavelengths since, as you've pointed out, c is always measured to be c locally.



The flaw in Einstein’s ideas that prevented him from discovering the “local ether” theory himself was that he did not acknowledge this “gravitational ether” as moving “through” space with astronomical bodies.

Dr. Su does realize that the "gravitational ether" does move through space with astronomical bodies, and, thus, it regulates the local speed of light at the bodies.

This doesn't seem to make any sense. Are you saying that moving objects leave behind some sort of gravitational wake in spacetime? If so, that doesn't seem to be the case. If it were, we'd expect to see, say, Jupiter dragging a tail of moons, asteroids, old space probes, and assorted junk behind it in its orbit. No such phenomenon has ever been observed. Heck, there is a whole group of asteroids that Jupiter's gravity has locked into position *ahead* of it in its orbit. Or are you saying that general relativity, as it is currently understood, ignores moving objects? That can't be the case since GR accurately predicts Mercury's perihelion advance even though the Sun is moving relative to the center of the galaxy. Or are you saying that spacetime itself is an absolute rest frame? That's also impossible because that would mean that you could view the universe in such a way that no object in the universe is seen to move, at any temperature. I don't see how that's possible.

Anyway, it sounds to me like Dr. Su is trying to create a distinction where none exists. That objects produce gravity even though they're moving has been understood for centuries. To date, *nothing* has been observed that suggests that motion distorts gravitational fields. What Einstein is saying is that spacetime itself is altered by the presence of matter and that alteration is what we experience as gravity. He is saying that the nature of spacetime is variable and that those variations must be taken into account. To suggest that he didn't realise that moving objects change the curvature of spacetime as they move would be to imply that Einstein never once considered things like planetary motion when formulating the theory. Since he accurately predicted very specific motions for Mercury, this doesn't seem to have been the case.

Sam5
2004-Feb-03, 03:17 AM
To be honest, it doesn't work. The same clock can't be used to make both measurements. To do this experiment, the clock has to be at rest relative to the gravity source when the light is emitted. It will also need to be at rest relative to the gravity source when it receives the light. If you use only one clock, you would have to accelerate it past the speed of light and the decelerate it to bring it back to a stop at the point where the light is received. This is impossible because the clock can't be in two places at the same time.

You merely calculate the different tick rates.

Sam5
2004-Feb-03, 03:25 AM
Sort of. What I'm saying is that the first scenario and the second scenario are essentially the same thing. You only observe the redshift or blueshift when the light changes its gravitational potential energy as it moves.

However, this does not require the light's *speed* to change. Again, it all comes down to a simple measure of energy conservation. You shoot light straight up from the surface of a planet with no atmosphere. Since it's moving away from the Earth's center of gravity, it is *gaining* gravitational potential energy.

The 1911 theory says the light is emitted redshifted due to the slow-down in the harmonic oscillation rates of the atoms, and the light speed changes, it speeds up, as the light moves upward.

See this statement by Max Abraham, 1912, also translated in Vol. 4 of “Collected Papers”:

“Already before period of one year A. Einstein, by accepting an influence of the gravitation potential on the speed of light, gave up the postulate of the constant speed of light essential for its earlier theory 1); in a work appeared recently 2);”

1) A. Einstein, Ann. d. Phys. 35. p 898. 1911.
2) A. Einstein. Ann. d. Phys. 38. p. 355. u. 443. 1912.

This was well-known back in that era. It has apparently been forgotten.

Sam5
2004-Feb-03, 03:31 AM
This doesn't seem to make any sense. Are you saying that moving objects leave behind some sort of gravitational wake in spacetime?

Doesn’t the earth’s gravity field move with it through space? I don’t know what you mean about the “wake”.