Time Dilation & big bang Question

[Neo]

With respect to time dilation...

During the Big Bang, when space was expanding explosively (probably at light speed?) -- what was time doing? Was time at a standstill (or very dilated) during the explosive growth of the three spatial dimensions? Or was time expanding explosively since it's in a continuum with space?

 

[Nenad]

With respect to time dilation...

During the Big Bang, when space was expanding explosively (probably at light speed?) --

about 3 seconds into the big bang, space expanged a lot faster than the speed of light, it had a growth spur. If you look a the age of the universe, (15 billion years), the size of it is more that 15 billion light years, making its expansion more than light speed at the beginning. And about your time question, I am not sure what you mean?

 

[Neo]

about 3 seconds into the big bang, space expanged a lot faster than the speed of light, it had a growth spur. If you look a the age of the universe, (15 billion years), the size of it is more that 15 billion light years, making its expansion more than light speed at the beginning. And about your time question, I am not sure what you mean?

Interesting but that is not a proof that space expanded faster than the speed of light. For instance, imagine that one part of space expanded diagnally downward toward the left and another part of space expanded diagnally upward toward the right -- both expansions at the speed of light. If you measure space from the bottom left to the top right, it is going to be more than 15 billion light years, but that is merely because space was traveling in different directions simultaneously. Right?

My question was about, what seems to me, a contradiction in the predictions of relativity theory. For instance, as a massive object expands at the speed of light, time comes to a stop. But what about the expansion of spatial dimensions? Did the expansion of the spatial dimensions during the Big Bang period slow down time or speed it up? That is, relativity implies that time slows (and eventually stops) for something that approaches the speed of light. It also teaches that space and time are in an inseparable continuum. So does time dilation not apply to the expansion of the spatial dimensions?

In other words, did time slow down during the Big Bang because space was expanding at light speed? Or does time dilation not apply to space itself?

 

[DrChinese]

Interesting but that is not a proof that space expanded faster than the speed of light. For instance, imagine that one part of space expanded diagnally downward toward the left and another part of space expanded diagnally upward toward the right -- both expansions at the speed of light. If you measure space from the bottom left to the top right, it is going to be more than 15 billion light years, but that is merely because space was traveling in different directions simultaneously. Right?

You are switching back to a more classical reference frame, and imagining that the diameter of a the universe is 30 billion LY. Actually, it is more like 150 billion light years in diameter for a 13.7 billion year old universe. That's a lot of expansion!

But you have a good point. Certainly there was a lot of time distortion in the early universe. As far as anyone knows, the rate of expansion of space itself is not affected by gravity. But experimental accuracy on this is poor at this time.

On the other hand, there may be interesting consequences on the development of the universe due to time dilation. DoctorDick has started a couple of threads to discuss this in Theory Development, and you might find the discussions there to be relevant.

 

[Neo]

You are switching back to a more classical reference frame, and imagining that the diameter of a the universe is 30 billion LY. Actually, it is more like 150 billion light years in diameter for a 13.7 billion year old universe. That's a lot of expansion!But you have a good point. Certainly there was a lot of time distortion in the early universe. As far as anyone knows, the rate of expansion of space itself is not affected by gravity. But experimental accuracy on this is poor at this time.On the other hand, there may be interesting consequences on the development of the universe due to time dilation. DoctorDick has started a couple of threads to discuss this in Theory Development, and you might find the discussions there to be relevant.

It doesn't have to be only 30 million LY based on my suggestion. I only described two dimensions with the diagnals. If you add depth to this, you might be able to account for the entire diameter. Besides, how was "150 billion years" derived?

But I think another way to account for it is because time itself was dilated by spatial expansion. That is, nothing ever moved faster than the speed of light, conforming to relativity. Instead, space expanded at the speed of light but because time itself was dilated, what seems to be 15 billion years was far longer in non-dilated time -- perhaps 150 billion years. The question arises if non-dilated time even exists if the expansion of all of space itself dilates time.

It seems to me that expansion of space is necessarily affected by the curvature of space ("gravity"). That's how the "Big Crunch" is derived.

Thanks but unfortunately I didn't find DrDick's threads remarkably insightful nor do I think he reached the same conclusions as I. They seem to be strewn with ad hominem and meaningless personality conflicts.

 

[DrChinese]

It doesn't have to be only 30 million LY based on my suggestion. I only described two dimensions with the diagnals. If you add depth to this, you might be able to account for the entire diameter. Besides, how was "150 billion years" derived?

But I think another way to account for it is because time itself was dilated by spatial expansion. That is, nothing ever moved faster than the speed of light, conforming to relativity. Instead, space expanded at the speed of light but because time itself was dilated, what seems to be 15 billion years was far longer in non-dilated time -- perhaps 150 billion years. The question arises if non-dilated time even exists if the expansion of all of space itself dilates time.

It seems to me that expansion of space is necessarily affected by the curvature of space ("gravity"). That's how the "Big Crunch" is derived.

For the calculation of the 150 billion LY value: Click here

There are still multiple issues to consider here.

Much if not most of the universe is receding from us at a speed that exceeds the speed of light. A substantial portion recedes from us faster than 2c. Objects have been observed as much as 3+c and there are certainly some objects moving considerably faster apart than that. The speed of light is a limit in a local reference frame per special relativity. It is not a limit when the expansion of space-time itself is considered as a component of velocity.

But I still think the point you are making is worth discussing. It would seem logical to me that time was dilated in the very early universe and that dilation would have been a significant component for a period of time. It would need to be considered in the early evolution of space and energy, but I wonder for how long? Seconds? A million years? Or maybe seconds that dilated into a million years? I haven't seen much on that subject.

 

[Neo]

For the calculation of the 150 billion LY value: Click here

There are still multiple issues to consider here.

Much if not most of the universe is receding from us at a speed that exceeds the speed of light. A substantial portion recedes from us faster than 2c. Objects have been observed as much as 3+c and there are certainly some objects moving considerably faster apart than that. The speed of light is a limit in a local reference frame per special relativity. It is not a limit when the expansion of space-time itself is considered as a component of velocity.

But I still think the point you are making is worth discussing. It would seem logical to me that time was dilated in the very early universe and that dilation would have been a significant component for a period of time. It would need to be considered in the early evolution of space and energy, but I wonder for how long? Seconds? A million years? Or maybe seconds that dilated into a million years? I haven't seen much on that subject.

Hmm...they don't demonstrate the derivation of "150 billion" though. I doubt its validity. Nonetheless, the idea of applying the Hubble law is interesting and (apparently) falsifies my idea -- that perhaps expansion of space causes time dilation. Or could it be possible that in regions where space itself is moving at greater than C there is a time loop. That is, where space is traveling greater than C, everything in that region travels backward in time?

 

[Neo]

Could this explain space's "infinite" nature? To clarify, if you move out enough, you'll be traveling faster than the speed of light. In these regions of space, time forms a loop upon itself. If you go to the edges of space, you will be traveling faster than the speed of light and will travel backward in time.

This would uphold the "infinite" nature of the universe. There is no limit -- it's just a time cycle.

 

[Neo]

Is it possible that the Heisenberg Uncertainty Principle be explained by relativity?

Electrons travel at close to the speed of light -- there must be a great degree of time dilation for electrons. Could this time dilation be one of the causes for the Uncertainty Principle?

 

[DrChinese]

Hmm...they don't demonstrate the derivation of "150 billion" though. I doubt its validity. Nonetheless, the idea of applying the Hubble law is interesting and (apparently) falsifies my idea -- that perhaps expansion of space causes time dilation. Or could it be possible that in regions where space itself is moving at greater than C there is a time loop. That is, where space is traveling greater than C, everything in that region travels backward in time?

The 156 billion LY diameter has some imprecision in it, no question. As we discover more and more high redshift (high z) objects it will be refined. But the basic idea is that an object traveling at N times the speed of light from us when it was emitted X billion years ago will be about (N * X) billion years away now. Plus add some for the subsequent expansion of the universe, and you get the answer. The point is there is a multiplier because as redshift (z) increases, so does N.

Dilation of time occurs even when there is no expansion of space, as has been shown in accelerators in many experiments. As far as anyone knows, there is no theoretical point at which time would move backward for anyone when objects move apart faster than c.

 

[Neo]

The 156 billion LY diameter has some imprecision in it, no question. As we discover more and more high redshift (high z) objects it will be refined. But the basic idea is that an object traveling at N times the speed of light from us when it was emitted X billion years ago will be about (N * X) billion years away now. Plus add some for the subsequent expansion of the universe, and you get the answer. The point is there is a multiplier because as redshift (z) increases, so does N.

Dilation of time occurs even when there is no expansion of space, as has been shown in accelerators in many experiments. As far as anyone knows, there is no theoretical point at which time would move backward for anyone when objects move apart faster than c.

I don't personally place much stock in the calculations -- they're indirect and not necessarily true, which is the point that I believe we both agree upon.

Are you implying that expansion of space at light speed cannot cause formation of matter and/or time dilation? If so, why?

In relativity, acceleration of a particle to luminal speed in vacuo as its limit causes formation of baryonic matter as a result of the energy-matter equivalence. What stops the speed of space expansion itself from causing formation of dark matter?

What if there are two subtypes of this close to light energy-to-matter conversion?

The first being what we normally expect:

1. Accelerate a mass particle to close to the speed of light and it will gain baryonic matter (due to energy-to-mass conversion).

2. Accelerate the universe to close to the speed of light and it will gain dark matter (due to the same).

Theoretical physicists don't seem to apply the implications of E=mc^2 to space itself -- why?

 

[mee]

For the calculation of the 150 billion LY value: Click here

There are still multiple issues to consider here.

Much if not most of the universe is receding from us at a speed that exceeds the speed of light. A substantial portion recedes from us faster than 2c. Objects have been observed as much as 3+c and there are certainly some objects moving considerably faster apart than that. The speed of light is a limit in a local reference frame per special relativity. It is not a limit when the expansion of space-time itself is considered as a component of velocity.

But I still think the point you are making is worth discussing. It would seem logical to me that time was dilated in the very early universe and that dilation would have been a significant component for a period of time. It would need to be considered in the early evolution of space and energy, but I wonder for how long? Seconds? A million years? Or maybe seconds that dilated into a million years? I haven't seen much on that subject.

If the universe has a width it has a center? Has anyone tried to find the center?

 

[Mike2]

For the calculation of the 150 billion LY value: There are still multiple issues to consider here.

Much if not most of the universe is receding from us at a speed that exceeds the speed of light. A substantial portion recedes from us faster than 2c. Objects have been observed as much as 3+c and there are certainly some objects moving considerably faster apart than that. The speed of light is a limit in a local reference frame per special relativity. It is not a limit when the expansion of space-time itself is considered as a component of velocity.

But I still think the point you are making is worth discussing. It would seem logical to me that time was dilated in the very early universe and that dilation would have been a significant component for a period of time. It would need to be considered in the early evolution of space and energy, but I wonder for how long? Seconds? A million years? Or maybe seconds that dilated into a million years? I haven't seen much on that subject.

If we can never actually observe anything that is receding faster than the speed of light, then how can you say ANY portion is receding faster than c?

 

[DrChinese]

If we can never actually observe anything that is receding faster than the speed of light, then how can you say ANY portion is receding faster than c?

1. Almost any photon observed from a distant object will be red-shifted. Such red shift occurs when the object that emitted it receding from us (ones that are approaching us are blue shifted, but these are much less common in an expanding universe). Such shift was noted originally almost 100 years ago by Hubble and others and was instrumental to our understanding that we live in an expanding universe.

2. Virtually any star or galaxy consists mostly of hydrogen and helium, and exhibits a known spectrum. The amount of red shift of the observed spectrum of a distant object can then be compared to the "standard" spectrum of similar elements at rest with respect to us. The difference is explained by General Relativity as representing velocity differential.

3. Interestingly, there is actually no theoretical upper limit to the amount of this differential. In fact, many objects have been spotted that are receding from us at more than twice the speed of light. This provides experimental confirmation of theory. It also means that the classical notion of a universe expanding at a maximum of c in one direction and c in another direction are wrong.

4. Thus your premise is wrong: we can and do observe light from objects that are receding from us at speeds far in excess of c. Such light has been moving towards us for over 13 billion years. The objects that emitted them are now about 46 billion LY away.

5. The full description of all of this is beyond the scope of a post. I might recommend this paper by Lineweaver and Davis, which pretty well explains everything:

http://arxiv.org/PS_cache/astro-ph/pdf/0305/0305179.pdf

 

[Neo]

Do you think it's possible for a singularity to exhibit wave-particle duality?

Is it impossible for a wave to affect the curvature of space?

 

[russ_watters]

Electrons travel at close to the speed of light -- there must be a great degree of time dilation for electrons. Could this time dilation be one of the causes for the Uncertainty Principle?

Electrons don't travel anywhere near the speed of light except when in a particle accelerator. And when talking about the speed of electrons around an atom, the term doesn't really have any meaning.

You may have the (common) misconception that when you flip a light switch, the light turns on when the electrons that were at the switch reach the light. In fact, its just like water in a pipe - when you open a valve, the wave-front moves at the speed of sound while the water itself may move relatively slowly. Thus, if a pipe is already full, opening a valve almost immediately results in water flowing out of the pipe - a wire is already full of electrons when you flip the light switch.

 

[Neo]

Do you think it's possible for a singularity to exhibit wave-particle duality?

Is it impossible for a wave to affect the curvature of space?

Singularities don't exhibit wave-particle duality because they are not in motion?

Wave motion from moving massive objects causes ripples in spatial curvature...

Are gravitational waves the only type of waves that affect spatial curvature?

Can non-gravitational waves affect curvature of space, such as, perhaps temporal waves? Is it possible to conceive of time as a wave that affects the curvature of space?


It is possible for a moving massive object's wave motion to temporarily weaken/reverse the supergravity of a singularity through gravitational wave "destructive resonance?"

 

[Chronos]

Singularities don't exhibit wave-particle duality because they are not in motion?

They are in motion.

Wave motion from moving massive objects causes ripples in spatial curvature...

Agreed.

Are gravitational waves the only type of waves that affect spatial curvature?

Gravitational waves do not affect spatial curvature, they follow the curvature.

Can non-gravitational waves affect curvature of space, such as, perhaps temporal waves? Is it possible to conceive of time as a wave that affects the curvature of space?

There is no observational evidence of that.

It is possible for a moving massive object's wave motion to temporarily weaken/reverse the supergravity of a singularity through gravitational wave "destructive resonance?"

Not according to current theory.

 

[Neo]

They are in motion..

Please clarify. If singularities are in motion and wave motion from moving massive objects causes ripples in spatial curvature, then why do singularities not exhibit wave-particle duality? Or is duality unnecessary for wave motion to result from a moving dense particle?

Gravitational waves do not affect spatial curvature, they follow the curvature.

"Gravity waves are ripples in the overall geometry of space and time." http://www.physics.gmu.edu/classinfo/astr103/CourseNotes/Text/Lec06/Lec06_pt2_txt_relativityGeneral.htm

But let us for the moment say that g waves don't affect space curvature. How is it then that you propose the effect of the massive body propagates? Apparently curvature does not instantaneously change -- a wave (that we call a gravity wave) curves space differentially at light speed.

There is no observational evidence of that.

My idea is that waves can affect curvature, just in different ways than particles. It seems that the influence of particles on curvature is highly localized whereas the influence of waves is (more) universal. It is as if the particle displaces an energy field and causes these gravity waves to propagate across time-space as a result.

Waves can cause pressure. Can a singularity be thought of as pressure on space? Perhaps it is possible for certain types of waves to affect curvature.

 

[Jim Beam]

you must forgive me when i say that i have trouble believing that the universe is, or ever has expanded at speeds faster than that of light. it would be believable if space time itself, by that term i mean tha amount of space possible for there to be objects present expanded at speeds far greater than c. as an analogy, i will use a cup of water. water flows from the faucet at a certain maximum speed and can't flow any faster. let's assume that this speed happens to be able to accupy a space, say, a figure pulled off the top of my head, 20 mL/second. it is flowing into a container that has a capacity of 1 liter. I can stand here watching it and if my sink was big enough, and i was strong enough, i could carry a bathtub and set it down in place of the liter sized container at a speed of a few seconds. in a few seconds, the water will only have filled up less than a cL. in a few seconds, i will have added (lets say 20 gal) of possible space for the water to accupy. that speed is far greater than the spead of the "expanding" water.

bottom line is that there is much more than meets the eye when it comes to our world, and saying that certain theories/laws are the way it has t be or the way it is quite foolish

 

[RingoKid]

wouldn't a singularity need a medium to propagate in as a wave and if that singularity then inflated outwards to become the universe then one would have to assume the medium was infinite and the universe finite but expanding infinitely into infinity ?

With regards to the wave affect,

If spacetime is water and an object beneath the surface repersents a body that causes the water to bend around it.

Then by virtue of the object moving, it creates ripples in the surrounding water that then interact with the ripples being created by every other object in motion. These would eventually even out to be discerned as no motion in spacetime or very hard to detect given that everything in the universe is in motion in relation to everything else.

Have i mentioned waves/ripples in a spherical pond before traveling outwards at the speed of light ?

 

[DrChinese]

you must forgive me when i say that i have trouble believing that the universe is, or ever has expanded at speeds faster than that of light. ... bottom line is that there is much more than meets the eye when it comes to our world, and saying that certain theories/laws are the way it has t be or the way it is quite foolish

You have only to believe the persuasive evidence. Many Type 1 supernovae have been seen which are receding from us far in excess of the speed of light. Theory is being adapted to be consistent with observation.

Personally, I think it is foolish to ignore evidence you don't like. The purpose of the scientific method is to remove personal prejudice from the equation.

 

[Garth]

You have only to believe the persuasive evidence. Many Type 1 supernovae have been seen which are receding from us far in excess of the speed of light. Theory is being adapted to be consistent with observation.

Sorry this just isn't correct. If the Type 1 supernovae were receding from us in excess of the speed of light they would be beyond our cosmic event horizon and their light would be "more than" infinitely red shifted so we couldn't see them.

I have no doubt that there are galaxies and supernovae beyond the event horizon which cannot be seen, however their superluminal velocity does not contravene SR because it is space-time itself which is expanding in GR, the galaxies etc. are just being carried along with it.

The Type 1 supernovae referred to are probably those distant S/N that are observed to be dimmer than expected by the standard theory previous predictions. It is therefore concluded (theory dependent - ancient S/N might just be intrinsically dimmer than more recent ones) that the universe has accelerated in its expansion rather than the usually predicted deceleration.

I hope this is helpful, Garth.

 

[jcsd]

Sorry this just isn't correct. If the Type 1 supernovae were receding from us in excess of the speed of light they would be beyond our cosmic event horizon and their light would be "more than" infinitely red shifted so we couldn't see them.

I have no doubt that there are galaxies and supernovae beyond the event horizon which cannot be seen, however their superluminal velocity does not contravene SR because it is space-time itself which is expanding in GR, the galaxies etc. are just being carried along with it.

The Type 1 supernovae referred to are probably those distant S/N that are observed to be dimmer than expected by the standard theory previous predictions. It is therefore concluded (theory dependent - ancient S/N might just be intrinsically dimmer than more recent ones) that the universe has accelerated in its expansion rather than the usually predicted deceleration.

I hope this is helpful, Garth.

No we can see objects in the universe that have recession velocites greater than c^*

* http://bat.phys.unsw.edu.au/~charley/papers/0310808.pdf

 

[Garth]

Now that was an interesting paper - thank you for bringing my attention to it.

However I believe confusion can still reign! We note that apart from their peculiar motion cosmological red shifts are not caused by the objects moving at all, cosmological red shift can be understood as a gravitational red shift caused by the photons being emitted deep in the universe's gravitational well, when it was smaller and more dense.

To measure velocity we have to measure distance and time. We therefore have to define both, and in an expanding universe specify whether we are talking about metric time, conformal time or some other transformation of time. Distance can be defined from time if the assumption is made that c is constant. (If we allow c to vary then other things vary with it such as the fine structure constant and we can become even more confused!)

Time can be defined so the universe isn't expanding at all, such as in Hoyle's mass-field theory and in the Jordan frame of Self Creation Cosmology.

Davis & Linewaver define the distance used to derive velocity to be the Proper distance D along a surface of constant time, dt=0, (Their paper quoted above eq 12 pg 18).

So such super-luminal objects referred to above are exceeding the velocity of light today, not when they emitted the photon that is received today.

I agree with that, under certain circumstances such velocities can exceed the speed of light.

My definition of velocity was their velocity at the time of emission, measured as the rate of change of distance along the surface of constant time then, not now.

 

[Mike2]

However I believe confusion can still reign! We note that apart from their peculiar motion cosmological red shifts are not caused by the objects moving at all, cosmological red shift can be understood as a gravitational red shift caused by the photons being emitted deep in the universe's gravitational well, when it was smaller and more dense.

Garth, do you feel this view has wide acceptance among cosmological scientists. I'm under the impression that they are ignoring changing gravitational effects of the universe as a whole. Thanks.

 

[Garth]

Mike2 - Cosmological Red shift of recession and cosmological gravitational red shift are the same thing interpreted from different perspectives. The former is as interpreted by a "3+1" observer, the latter as interpreted in "4" space-time. Remember we do not see galaxies/quasars/S/N receeding at all, we see red shift and interpret it as recession.
Garth

 

[Mike2]

Mike2 - Cosmological Red shift of recession and cosmological gravitational red shift are the same thing interpreted from different perspectives. The former is as interpreted by a "3+1" observer, the latter as interpreted in "4" space-time. Remember we do not see galaxies/quasars/S/N receeding at all, we see red shift and interpret it as recession.
Garth

Thank you, but my question is how prevalent is this alternative interpretation of redshift being due to universal gravity. Is this main stream, or are you only talking about your own understanding of the situation? Thanks.

 

[hellfire]

My definition of velocity was their velocity at the time of emission, measured as the rate of change of distance along the surface of constant time then, not now.

If I understood your definition correctly I think you are incorrect anyway. An object having a speed v = c wrt to us now, had a speed v > c wrt to us in the past. This is due to the fact that, although it was closer wrt to us, the Hubble parameter was greater (much greater) than now. Try some values of z in this calculator:

http://www.earth.uni.edu/~morgan/ajjar/Cosmology/cosmos.html

for Matter Density = 0.27, Cosmological Constant = 0.73 and Hubble parameter today = 71 and look at ?speed away from us now? and ?speed away from us then?. The calculator is based on a mumerical integration of the Friedmann equation.

 

[Garth]

Mike2 - It is sometimes acknowleged, and was stressed by maverics like Fred Hoyle. The mathematics is to be found in Synge - "Relativity the General Theory" 1955 and referred to by people like Dicke. Synge had an interesting twist to the interpretation. His view was that all gravitational red shifts, even between objects that are at rest wrt each other at different levels in a gravitational potential well are doppler shifts. The worldlines of such objects are just diverging in space-time due to curvature. This interpretation of Synge has been criticised in the publications although I don't have the reference now.
My view is that taking the '4' view of a block space-time there is no movement. World lines may diverge or converge because of curvature or inertial forces and one 'draws' the null-geodesics between them. Two wave fronts originating on one object's worldline cross another's worldline at a greater or lesser local time interval apart and hence the phenomena is interpreted as a red or blue shift. If there is no movement in such a view, as time is already in the diagram, then it may be misleading to call it doppler shift as Synge does, gravitational red/blue shift will do very nicely. It also confuses between gravitational or cosmological red/blue shifts and actual doppler shifts caused by real motion within space-time. So I call gravitational red shift just that and understand that cosmological red shift may be interpreted as the same phenomenum.

hellfire - Well spotted! You are correct for a decelerating universe , however Davis and Linewaver were also considering accelerating universes as is thought to be observed from the distant type Ia S/N data. In such a universe the reverse is true and it is in those universes that objects can be observed today as they were in the distant past, when their velocities were sub-luminal, which are receeding from us today at super-luminal velocities.

If cosmological red shift is interpreted as cosmological recession then the crucial distance may not be that along our present space-like 'now' membrane dt=0 when observed, but along the space-like 'then' membrane when emitted. It is a matter of interpretation and definition.

Converting red shift to velocity is theory dependent, which formula do you use? The classical one, the SR one or a GR one? Davis and Linewaver are perfectly entitled to use their definition but there are others who would see things differently and who therefore may come to different conclusions to them. The confusion they refer to may be just one of convention (of definitions) rather than substance.

In my view, if cosmological red shift is to be understood as velocity rather than gravity then I prefer to understand that the red shift approaches infinity as the velocity approaches c and hence the object cannot be seen if v = c or v > c.