No, the Big Bang theory is not 'broken.' Here's how we know.

[rod]

That would require infinite space and that is contrary to my understanding of BBT. I keep thinking about the claims that, just after Inflation, the universe was about the size of a grapefruit (or beach ball from one source). It's hard enough for the mind to grasp the 90+ billion lyrs. diameter today.

Yes, it is hard Helio My post #23 shows what happens extrapolating H0 with GR expansion beyond the comoving radial distance of the postulated 1100 redshift for the CMBR. You run into more space, expanding even faster Extrapolating backwards to the *beginning*, you land in a singularity

 

[rod]

"That would require infinite space and that is contrary to my understanding of BBT."

Interesting, I found this information about infinite space in the BB model.

Is space infinite? We asked 5 experts, https://www.swinburne.edu.au/news/2... the observable universe,time of the Big Bang.

It looks like the answer is up in the air

 

[billslugg]

From what I've read, space is infinite but bounded. Go figure that one out.

There is no preferred location, every locations sees itself at the center.

There is no preferred direction, no "up" or "down".

There is, however, a preferred velocity. That velocity that shows the CMBR to be the same in all directions. The dipole anisotropy we observe shows we are moving 700 km/sec in the direction of the constellation Leo. This would resolve the Twin Paradox. The travelling Twin's clock would slow down while the Twin at home would not experience time dilation. This would also imply that our clocks here on Earth are at .999997 of the absolute time standard.

 

[Helio]

"That would require infinite space and that is contrary to my understanding of BBT."

Interesting, I found this information about infinite space in the BB model.

Is space infinite? We asked 5 experts, https://www.swinburne.edu.au/news/2... the observable universe,time of the Big Bang.

It looks like the answer is up in the air

Those answers are typical. But notice how they seem to never mention the size suggested just after Inflation — ranging from a tennis ball to a beach ball. It’s hard to start small and jump to infinity, so maybe they have a reason in doing so, which would be interesting.

 

[Helio]

From what I've read, space is infinite but bounded. Go figure that one out.

There is no preferred location, every locations sees itself at the center.

There is no preferred direction, no "up" or "down".

I suspect the idea is that there is no edge to this finite universe, thus it goes on forever. “Infinity” may be an expression for this. GR allows even light to go straight thru bent space and, eventually hit us in the back of the head.

There is, however, a preferred velocity. That velocity that shows the CMBR to be the same in all directions. The dipole anisotropy we observe shows we are moving 700 km/sec in the direction of the constellation Leo. This would resolve the Twin Paradox. The travelling Twin's clock would slow down while the Twin at home would not experience time dilation. This would also imply that our clocks here on Earth are at .999997 of the absolute time standard.

But even the Hubble Flow is not an absolute frame. The same time dilation effects for the traveler is independent of which planet they leave or which direction they travel, AFAIK.

It’s still odd that the Hubble Flow is a unique frame, admittedly.

 

[billslugg]

"The same time dilation effects for the traveler is independent of which planet they leave or which direction they travel, AFAIK." - Helio

Yes, this is what we've been taught but I have been reading up on the Twin Paradox and Lorentz Contraction and it is getting me very confused. I used to think that Lorentz Contraction was the same looking forward, sideways or backwards but this is not true. Looking out the windshield of the spaceship, the oncoming scenery is indeed contracted. However looking out the side window, there is no contraction, the objects are actually rotated slightly so one can see their back side. (See Terrell Rotation) Looking out the rear window things are not contracted but are stretched.

The Twin Paradox resolution is usually explained as "Special Relativity" does not apply here and one must use the extremely complicated formulas in GR, which will explain it.

I am beginning to wonder if time dilation might follow a similar pattern but I have not read that anywhere. I am still delving into things.

 

[Helio]

Looking out the windshield of the spaceship, the oncoming scenery is indeed contracted. However looking out the side window, there is no contraction, the objects are actually rotated slightly so one can see their back side. (See Terrell Rotation) Looking out the rear window things are not contracted but are stretched.

Yes, though the side window is a little more complicated. The colors and the brightness are different as well.

The Twin Paradox resolution is usually explained as "Special Relativity" does not apply here and one must use the extremely complicated formulas in GR, which will explain it.

I think SR is all one needs, but it's not something a normal mind can get around, so I haven't.

Here is a paper that seems to have the approach of a similar paper I really liked, but can't find. The solution to the "paradox" is done graphically to illustrate what the math is saying. But geometry is still limited in grasping what's really happening. It's just the best I've seemed to have found, so far.

I had hoped that dilation could be explained by fast objects skipping over time "waves" just as a very fast boat skips over waves. Just as the boat displaces less and less water with speed, time would be "displaced" less and less with a fast space ship. Time does seem to come in increments - Planck time units, so this is another argument in its favor, I think.

Unfortunately, this will assume space to be absolute, and that is anathema to Relativity. Still, given the uniqueness of the Hubble Flow, I hope some greater mind can find a way to make it work. It would give us all some physicality to time dilation.

 

[billslugg]

If one accepts that time and space are manifestations of the same underlying "thing", then when you travel fast you experience more space thus time is taken away from you.

 

[Helio]

If one accepts that time and space are manifestations of the same underlying "thing", then when you travel fast you experience more space thus time is taken away from you.

That’s kinda clever. Making the product of ftine and space s constant might do this. But relativity still rejects this since the traveler sees Earth clocks as slower.

 

[billslugg]

This is at the root of the Twin Paradox. If they are moving relative to each other and each sees the other's clock as slower then each will see the other as younger when they finally meet. They can't both be younger. Either one is younger or they are of the same age.

Here is what I have gleaned:

In the classic Twin Paradox (Twin A stays on Earth, Twin B rockets into space) the two reference frames are not equivalent. Main objection: Twin B experienced acceleration and Twin A did not. (Langevin 1911) This was laid out by Einstein in 1905 when he stated that the clock that underwent acceleration would run slower. See Wiki article on Twin Paradox, "History".

Thus the "Three Twins" proposal: (von Laue 1913)
Twin A stays on Earth, Twin B rockets by and clocks are synchronized, later on way far out in space TwinB synchronizes clocks with Twin C who is heading towards Earth. When Twin C arrives at Earth he compares clocks with Twin A. Thus no acceleration is involved. Main objection: One frame of reference in the stationary twin, two frames of reference in the travelling twins. Not an equal comparison.

How about "Four Twins". (I am making this one up.) Twins A and B pass by Earth at the same time, one going west and one going east, and they synchronize clocks. After awhile they each encounter a twin coming in the opposite direction, synchronize clocks and then who pass each other when they reach Earth, then they compare clocks. This is a perfectly symmetrical exercise, there can be no difference between the two when they pass each other, yet Special Relativity would argue each sees the other one as younger. Since each side is a mirror image they must be the same age when they meet.

Lorentz contraction has a different sign based on whether you are approaching or receding. Perhaps time dilations acts similarly.

 

[Helio]

This is at the root of the Twin Paradox. If they are moving relative to each other and each sees the other's clock as slower then each will see the other as younger when they finally meet. They can't both be younger. Either one is younger or they are of the same age.

Yes, but the traveler will "see" the Earther as aging slower due to the time it takes the light from Earth to reach the Traveler. This is cosmetic, admittedly, because they will both agree that the Traveler arrived to, say, Proxima b, faster due to time (or distance) dilation. [Of course, Earthers will have to wait 4.3 years to see and verify the dilation.]

Here is what I have gleaned:

In the classic Twin Paradox (Twin A stays on Earth, Twin B rockets into space) the two reference frames are not equivalent. Main objection: Twin B experienced acceleration and Twin A did not. (Langevin 1911) This was laid out by Einstein in 1905 when he stated that the clock that underwent acceleration would run slower. See Wiki article on Twin Paradox, "History".

Yes, but it's worth noting that the acceleration itself won't encapsulate the time dilation since one can accelerate an object (atomic clock) in hardly any time at all and the time difference will also be about any time (change) at all.

Some have called this a symmetry brake, yet seem never able to explain where acceleration got the hammer to break it.

Thus the "Three Twins" proposal: (von Laue 1913)
Twin A stays on Earth, Twin B rockets by and clocks are synchronized, later on way far out in space TwinB synchronizes clocks with Twin C who is heading towards Earth. When Twin C arrives at Earth he compares clocks with Twin A. Thus no acceleration is involved. Main objection: One frame of reference in the stationary twin, two frames of reference in the travelling twins. Not an equal comparison.

You're probably beyond my knowledge of SR to help, but I think Twin C will easily demonstrate time dilation for Twin B, and for Twin C during the return period.

What "appears" unique about all this gets back to Mach, who argued that the mass of the universe gives us things like inertia. The Earth is essentially moving at the speed of the Hubble Flow, so it's as if anything that accelerates relative to it receives time dilation effects. Yet, this isn't correct with Relativity.

Notice that even Twin C must have accelerated relative to the Hubble Flow in order to do what you describe. This alters those graph lines I mentioned showing that the time dilated pathway is not Earth's path line.

 

[billslugg]

If time is dilated because the traveller is moving away from us then time must be sped up when the traveller is moving towards us. The two effects would counter each other and when the twin arrived back at Earth they would both be the same age.

 

[Unclear Engineer]

Looking at the link Helio posted earlier ( http://www.owl232.net/papers/twinparadox.pdf ), it seems to me that the "paradox" comes from incorrectly assuming that the inbound and outbound inertial frames of reference are identical in their effects for the differences in the experiences of the "Earth-bound" twin and the "space-traveling twin". That link makes it pretty obvious that there are basically 3 frames of reference that are inertial, and that you need to stay in one at a time to figure out what the result will look like in that frame. And, the link shows that the frames for the Earth twin and the space twin while traveling away will give the same quantitative result for the age difference that occurs after the Earth twin has experienced 20 years of time while staying there.

Since this thought experiment would crush any actual physical thing if tried in the real world, due to the assumed instantaneous accelerations to large fractions of light speed, it seems that we are going to be forever stuck trying to relate such things to the real world.

On the other hand, we do seem to have actual physical experiments in the form of GPS satellite clock corrections that do seem to validate the time dilation effects of both the Special Theory of Relativity and the General Theory of Relativity. So, unless somebody can show me how those measured effects are either wrong or being mis-interpretted, it seems that we have proven 2 things:
1. time really is dilated by relative motion and by proximity to mass, and
2, we are really poor at being able to comprehend how this works, except by doing the math correctly, in accordancwe with the actual theory.

 

[Helio]

If time is dilated because the traveller is moving away from us then time must be sped up when the traveller is moving towards us. The two effects would counter each other and when the twin arrived back at Earth they would both be the same age.

This would be somewhat what the two parties would see since light doesn’t have infinite speed, but the very motion of the traveler causes the dilation effects as determined by both parties, especially upon return. The ship time will dilate regardless of direction.

Or, the other twist that has the same result, is the view that length contracts. Perhaps length contraction (Lorentz, and others) is an easier mental picture. The idea, of course, is the ship arrives sooner (either direction) because it travels less distance due to speed alone.

But let’s not forget that you only get to pick one effect to calculate dilation. Either time dilates or space contracts, not both. [I suppose one could blend the two, but don’t ask me to do so. Is sanity an asset?]

 

[Helio]

Looking at the link Helio posted earlier ( http://www.owl232.net/papers/twinparadox.pdf ), it seems to me that the "paradox" comes from incorrectly assuming that the inbound and outbound inertial frames of reference are identical in their effects for the differences in the experiences of the "Earth-bound" twin and the "space-traveling twin". That link makes it pretty obvious that there are basically 3 frames of reference that are inertial, and that you need to stay in one at a time to figure out what the result will look like in that frame. And, the link shows that the frames for the Earth twin and the space twin while traveling away will give the same quantitative result for the age difference that occurs after the Earth twin has experienced 20 years of time while staying there.

Since this thought experiment would crush any actual physical thing if tried in the real world, due to the assumed instantaneous accelerations to large fractions of light speed, it seems that we are going to be forever stuck trying to relate such things to the real world.

On the other hand, we do seem to have actual physical experiments in the form of GPS satellite clock corrections that do seem to validate the time dilation effects of both the Special Theory of Relativity and the General Theory of Relativity. So, unless somebody can show me how those measured effects are either wrong or being mis-interpretted, it seems that we have proven 2 things:
1. time really is dilated by relative motion and by proximity to mass, and
2, we are really poor at being able to comprehend how this works, except by doing the math correctly, in accordancwe with the actual theory.

This is why I chose engineering. Which is crazier: quantum physics or relativity?

 

[billslugg]

Additional reading has shown me that time dilates no matter which direction you are moving and occurs as seen by both twins. In fact, when the two twins meet back at Earth during a "fly by" both sees the other one as younger. They are in separate reference frames which is how this happens. In order for them to be in the same reference frame one must decellerate which is not accounted for in SR but must be figured out in GR.
Brief pause to allow brain to cool down.

 

[Unclear Engineer]

Well, I'd answer "quantum physics" seems crazier. My reasoning is that relativity provides tests that can be done without "imagining" things that we can't actually measure or even define. At least we can see clocks disagree and the apparent positions of stars change as light goes by massive objects. And there are also orbital precession measurements.

On the other hand, quantum physics starts by embracing the idea that things like photons have a "dual nature" of waves and particles, and we have no physical analogy to use to understand that in our macro world. So, there seems to be a "relaxed" attitude among quantum physicists to the extent that, if it seems to work out in their theory, then it must be correct. So, there are concepts like "fileds" that exist in all space, whether or not there are particles in that space to generate a field. What an engineer calls a field is turned on its head, so that electons are "waves" in an independent "field" instead of the electron generating a measureable "field" of effects in its vicinity. And, that seems to have some incomprehensible incompatibilities with the Michelson-Morely results that show we can't measure velocity through an "ether" that is hypothesized to be the transmission medium for light, i.e., "photons".

So there seems to be a pretty hard-to-bridge disconnect between macro system General Relativity and quantum level sized physical interpretation.

I think we are seeing the damage of that disconnect in cosmology, as we try to make one theory consistent from the macro astronomy measurements we make today through an extrapolation back in time into the quanum world to get to a "Big Bang" condition. I tried in another thread to get people to think about how we understand photons, starting with a visible light energy one not long after the "Bang" and using the theorized "inflation of space" to increase the size of the photon to macro measurement size. That discussion went off-the-rails and was stopped. So, there still seems to be no aggreement on how to conceive of that inflation of a high energy photon with "dual wave/particle characteristics" into a microwave radio wave that we are all familiar with. But, that is what the current LambdaCDM model of the universe hypothesizes did happen, not just to photons, but to everything.

So, at least until we can get a single theory that can unify both relativity and quantum mechanics, I have serious doubts about whether the current cosmology models are properly conceptualized.

 

[Helio]

Additional reading has shown me that time dilates no matter which direction you are moving and occurs as seen by both twins. In fact, when the two twins meet back at Earth during a "fly by" both sees the other one as younger. They are in separate reference frames which is how this happens.

That seems odd to me. The Proxima b twin arrival would prove time had dilated regardless if the ship stopped or zipped by. The opposite direction would present the same dilation circumstance, right?

In order for them to be in the same reference frame one must decellerate which is not accounted for in SR but must be figured out in GR.

SR actually can solve for accelerations using iterations. I think I read where this is easier math.

 

[Unclear Engineer]

SR actually can solve for accelerations using iterations. I think I read where this is easier math.

That is an assumption that I am not ready to accept.

We are already in a "pickle" trying to conceptualize the relationships between inertial frames of highly different relative speeds and directions. Assuming that non-inertial effects can be properly quantified by integrating over an infinite number of infinitesimal changes in relative velocity may seem rational. But a good theoretical mathematician might tell us that what we are really doing is accumulating an infinite amount of error at an infiinte number of disjointed junctions in the various "realities" of the assumed infinite number of inertial frames of reference.

 

[Unclear Engineer]

One of the things that struck me about the time dilation corrections for GPS satellites is that the integrated net velocity (i.e., the vector including direction) of the satellite with respect to the Earth is nearly zero after a substantial period of time, since the satellite is moving in a circle arount the Earth, but the time dilation error apparently continues to accumulate over time as a simple function of the orbital velocity.

 

[billslugg]

The "zipping by" concept avoids any acceleration consideration which keeps GR out of it.
Yes, apparently the "net velocity" is irrelevant. Doesn't matter whether the craft is going away, sideways or towards the observer as far a time dilation is considered.

 

[Helio]

That is an assumption that I am not ready to accept.

We are already in a "pickle" trying to conceptualize the relationships between inertial frames of highly different relative speeds and directions. Assuming that non-inertial effects can be properly quantified by integrating over an infinite number of infinitesimal changes in relative velocity may seem rational. But a good theoretical mathematician might tell us that what we are really doing is accumulating an infinite amount of error at an infiinte number of disjointed junctions in the various "realities" of the assumed infinite number of inertial frames of reference.

I suspect they are solving for uniform acceleration, which should allow for considerable accuracy in calculating those many, but not infinite, number of inertial frames.

 

[Helio]

The "zipping by" concept avoids any acceleration consideration which keeps GR out of it.
Yes, apparently the "net velocity" is irrelevant. Doesn't matter whether the craft is going away, sideways or towards the observer as far a time dilation is considered.

Yes. GPS has to account for both SR and GR. Interestingly, they produce counter dilation effects, but not equal to one another.

 

[Unclear Engineer]

I suspect they are solving for uniform acceleration, which should allow for considerable accuracy in calculating those many, but not infinite, number of inertial frames.

I am not sure that accounts for the potential misfit errors. Remember, we are talking about a situation that does not seem to make sense to us, and leaning heavily on the math to figure it out. If we do the math wrong, we get the wrong answer - and probably would not know it.

I am remembering back to my first semester in college, where I had been signed up for an "advanced" math class, mainly because I had good grades in math in high school. After the professor in that course had spent the whole semester "proving" that mathematical integration was "proper", while I had been actually doing a lot of it for the physics class I was taking at the same time, I realized that, as an engineer, what I really needed was not an extremely rigourous proof that it was OK to do it, but rather some training on how to do it for the various expressions I needed to integrate for my physics classes. So, I changed math course trajectories.

But, I still remember there were a lot of the theoretical nits that math professor went through to prove that integration was "OK". And some of them related to the continuity of the function across the range of the integral. That is where I am getting a mental red flag on subsituting a series of inertail frames of reference for an accelerating frame of reference.

 

[billslugg]

I agree, no amount of manipulating a series of inertial frames of reference can substitue for GR.