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Old 23rd January 2021, 04:06 PM   #1761
Reformed Offlian
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Originally Posted by Reformed Offlian View Post
OK, so how does one measure the "photon's odometer", if not by redshift? What is the measurement one takes?
Also, you're still stuck with the fact that observers in your model would not agree on the value of v, and thus could not agree on a value for D. In my scenario, the earthbound observer sees the light from GN-Z11 to be traveling towards him at a speed >0. The aliens on the spaceship do not.

Last edited by Reformed Offlian; 23rd January 2021 at 04:16 PM.
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Old 23rd January 2021, 04:17 PM   #1762
Mike Helland
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Originally Posted by Ziggurat View Post
Sometimes you can, sometimes you can't. So what? The fact that you can't always figure out something from limited information doesn't mean the information doesn't exist somewhere.
Ok.

But the issue is the observers will have came to their own conclusions about D, which will differ.

How is it that these observers know the distance a single photon has traveled, but I don't know that as an observer in the physical world?
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Old 23rd January 2021, 04:20 PM   #1763
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Originally Posted by Reformed Offlian View Post
Also, you're still stuck with the fact that observers in your model would not agree on the value of v, and thus could not agree on a value for D.
The photon already has a singular value for D.

v is calculated from it.
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Old 23rd January 2021, 04:21 PM   #1764
Reformed Offlian
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Originally Posted by Mike Helland View Post
The photon already has a singular value for D.

v is calculated from it.
And how does one determine D?
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Old 23rd January 2021, 04:31 PM   #1765
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Originally Posted by hecd2 View Post
Doesnít the fact that you are so wrong about so many fundamental aspects of physics (several this evening alone) ever make you stop and think that you havenít got the background to seriously challenge numerous well-established theories?
Of course.

But its not like dark energy or the inflationary multiverse are old, stalwarts of physics. These are ideas that people came up with in our life time, and it hasn't produced any technology or lab results, and the measurements of the expansion of space aren't agreeing, so I don't see the harm in finding out what an alternative might predict before the JWST goes up. Even if its all nonsense, it makes more sense to predict what it will show rather than simply wait and adapt the standard model after the fact that.
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Old 23rd January 2021, 04:32 PM   #1766
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Originally Posted by Reformed Offlian View Post
And how does one determine D?
It's a variable in the model, photon.d.
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Old 23rd January 2021, 04:32 PM   #1767
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Originally Posted by Mike Helland View Post
The photon already has a singular value for D.

v is calculated from it.
You're also still stuck with the fact that the earthbound observer can see that, for GN-Z11, v>0, while the aliens can see that it is not.
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Old 23rd January 2021, 04:33 PM   #1768
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Originally Posted by Mike Helland View Post
It's a variable in the model, photon.d.
I know it's a variable. I asked you how does one measure it.
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Old 23rd January 2021, 04:39 PM   #1769
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Originally Posted by Reformed Offlian View Post
I know it's a variable. I asked you how does one measure it.
The same way one measures the mass of one of these objects:

Code:
object1 = {
	xyz: [0,0,0],
	mass: 1
}

object2 = {
	xyz: [3,4,5],
	mass: 2
}
If the question is what does a purely physical observer know about the model in which it exists, it would observe redshifs, and calculate a z. The peculiar motion of the observer would be included in that, but that's true for either interpretation of redshifts.

But that's not what is meant when we ask what does an observer see, because no such model actually exists. What we mean when we ask what an observer sees comes from the model's variables. They can be transformed in various ways, but it's still the variables that are being transformed.
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Old 23rd January 2021, 04:48 PM   #1770
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Originally Posted by Mike Helland View Post
The same way one measures the mass of one of these objects:

Code:
object1 = {
	xyz: [0,0,0],
	mass: 1
}

object2 = {
	xyz: [3,4,5],
	mass: 2
}
If the question is what does a purely physical observer know about the model in which it exists, it would observe redshifs, and calculate a z. The peculiar motion of the observer would be included in that, but that's true for either interpretation of redshifts.
OK, so it sounds like we *are* deriving D from redshift measurements. What is the rest frame we are using? If the earthbound observers tell the aliens that they have a peculiar velocity of .1c, and the aliens shoot back with: "No, U!" who is right?
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Old 23rd January 2021, 04:52 PM   #1771
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Originally Posted by Reformed Offlian View Post
OK, so it sounds like we *are* deriving D from redshift measurements. What is the rest frame we are using? If the earthbound observers tell the aliens that they have a peculiar velocity of .1c, and the aliens shoot back with: "No, U!" who is right?
You missed a qualifier.

If we were using something like an Everett observer to obtain predictions from the model, that's how the observer would do it.

That's not how you measure distances in special relativity.

That's not how anything is actually is done, because no one has built such an observer yet.

I'm saying the photon has a D, and that's the value used.

You're trying to formulate D some other way, which is unnecessary since it's already there.
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Old 23rd January 2021, 05:02 PM   #1772
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Originally Posted by Mike Helland View Post
You missed a qualifier.

If we were using something like an Everett observer to obtain predictions from the model, that's how the observer would do it.

That's not how you measure distances in special relativity.

That's not how anything is actually is done, because no one has built such an observer yet.

I'm saying the photon has a D, and that's the value used.

You're trying to formulate D some other way, which is unnecessary since it's already there.
No, I'm asking you how you determine the value of D. Different observers in the same vicinity will see different values for v in your model, since some would observe light from distant galaxies coming to them at v>0 and others would not. Those indicate different values for D

Who has the right value for D?

Last edited by Reformed Offlian; 23rd January 2021 at 05:03 PM. Reason: added bold for emphasis
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Old 23rd January 2021, 05:07 PM   #1773
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Originally Posted by Reformed Offlian View Post
No, I'm asking you how you determine the value of D. Different observers in the same vicinity will see different values for v in your model, since some would observe light from distant galaxies coming to them at v>0 and others would not. Those indicate different values for D

Who has the right value for D?
Here is what I'm suggesting.

Take the value of photon.d, put it into the formula v=c-HD, and find v.

You're suggesting the observer knows v, and calculates D from it.

That's the mistake.
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Old 23rd January 2021, 05:20 PM   #1774
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Originally Posted by Mike Helland View Post
Here is what I'm suggesting.

Take the value of photon.d, put it into the formula v=c-HD, and find v.

You're suggesting the observer knows v, and calculates D from it.

You've proposed an equation: v=c-HD. I'm not limited to only solving for v, given values for D. Equations work both ways.

Quote:
That's the mistake.
It's not a mistake to say that an observer who sees light knows that that light is traveling towards him at v>0.

It's not a mistake to say that an observer whom that light never reaches knows that it isn't.

It's not a mistake to make inferences about D in your model, based on what we observe about v.

What it *is* is a problem that you need to deal with.

Which observers will have the right values for D?
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Old 23rd January 2021, 05:22 PM   #1775
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Originally Posted by Reformed Offlian View Post
It's not a mistake to say that an observer whom that light never reaches knows that it isn't.
How do you know what will never reach you?

You're causally connecting two causally disconnected objects.
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Old 23rd January 2021, 05:38 PM   #1776
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Originally Posted by Mike Helland View Post
Of course.

But its not like dark energy or the inflationary multiverse are old, stalwarts of physics.
I wasnít referring specifically to problems with your understanding of modern cosmology, such as the features of the CMB and what they mean, although in fact your understanding of those is deficient as well (see above), but fundamental misunderstandings that you have about foundational aspects of Relativity, thermodynamics, quantum mechanics, and in fact almost all of physics. Whatís more is that in order for your hypothesis to work, you are compelled to throw all these under a bus, and it doesnít matter to you because you donít understand them in the first place.
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Old 23rd January 2021, 05:44 PM   #1777
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Originally Posted by hecd2 View Post
I wasnít referring specifically to problems with your understanding of modern cosmology, such as the features of the CMB and what they mean, although in fact your understanding of those is deficient as well (see above), but fundamental misunderstandings that you have about foundational aspects of Relativity, thermodynamics, quantum mechanics, and in fact almost all of physics. Whatís more is that in order for your hypothesis to work, you are compelled to throw all these under a bus, and it doesnít matter to you because you donít understand them in the first place.
Understood.

Here's how I look at it.

Classical physics, relativity, and quantum mechanics all operate under the assumption that light can travel to infinity.

In 1929, after these things had been established the redshifts were discovered. No one had ever seen millions of light years away, and we found something new.

Light is supposed to go to infinity without losing energy. So the redshifts were taken as expansion.

That path has led us to some pretty incredible things, like the inflationary multiverse, and some head scratching results and anomalies.

Do you really believe that stuff?
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Old 23rd January 2021, 05:49 PM   #1778
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Originally Posted by Mike Helland View Post
How do you know what will never reach you?
Because the light never reaches me. In fact, no light from GN-Z11 ever reaches me, even the light that's presumably hundreds of millions of years older.

Quote:
You're causally connecting two causally disconnected objects.
Right, because the light will never reach me at v>0. Unlike Earth.

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Old 23rd January 2021, 05:58 PM   #1779
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Originally Posted by Reformed Offlian View Post
Because the light never reaches me.
So if I have this straight.

The model provides D, which can be used to calculate v of the photon.

And you're claiming, the space ships knows the v of photons it will never interact with, despite it not being provided directly by the model, in order to obtain D, which is already directly provided by the model.

Do I have that right?
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Old 23rd January 2021, 06:32 PM   #1780
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Originally Posted by Mike Helland View Post
So if I have this straight.

The model provides D, which can be used to calculate v of the photon.
It also provides redshift.

E_observed = E_emitted ◊ v/c
= E_emitted ◊ (c - H ◊ D)/c

That's your model for cosmological redshift, yes? If I know the redshift, I can estimate v.

Quote:
And you're claiming, the space ships knows the v of photons it will never interact with, despite it not being provided directly by the model, in order to obtain D, which is already directly provided by the model.

Do I have that right?
You forget that the space ship can communicate with earth via normal c-speed photons (which actually has some rather wonky implications for light cones that you might want to think some more about). So the aliens can learn all about GRBs from a nearby observer even though they can't see the GRB themselves.

And the aliens can have information about what the redshift of that galaxy is, as seen from earth. Which means they can estimate what v must be relative to Earth.

Since the aliens can exchange signals with Earth, they can also estimate their distance from Earth, and their speed relative to earth and thus estimate an ETA for light from the GRB, for various relative values of v. Which means they can subsequently realize that they're not getting any light from the GRB consistent with the estimated value for v, once aforementioned ETA comes and goes. In fact, they won't be getting any light from GN-Z11 at all, in spite of its presumably being hundreds of millions of years older than the GRB it hosts.

From all the above, yes, the aliens can work out that they will never see any light from the GRB.
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Old 23rd January 2021, 06:39 PM   #1781
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Originally Posted by Reformed Offlian View Post
It also provides redshift.

E_observed = E_emitted ◊ v/c
= E_emitted ◊ (c - H ◊ D)/c

That's your model for cosmological redshift, yes? If I know the redshift, I can estimate v.
You've assumed v in the first equation.

Quote:
You forget that the space ship can communicate with earth via normal c-speed photons (which actually has some rather wonky implications for light cones that you might want to think some more about). So the aliens can learn all about GRBs from a nearby observer even though they can't see the GRB themselves.
I recall.

Do you think that this means the ship sees the photons at a negative speed?


Quote:
From all the above, yes, the aliens can work out that they will never see any light from the GRB.
Ok.

Does that justify the conclusion that the ship sees the photons traveling at a negative speed?
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Old 23rd January 2021, 06:50 PM   #1782
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Originally Posted by Mike Helland View Post
You've assumed v in the first equation.
No, I didn't. I can solve for c-HD by calculating E_observed/E_emitted, IOW, by calculating redshift. No assumptions about v required.

Quote:

I recall.

Do you think that this means the ship sees the photons at a negative speed?
No, I don't think that's what happens. I leave it up to you whether that's what happens in your model.

Quote:
Ok.

Does that justify the conclusion that the ship sees the photons traveling at a negative speed?
Probably not. I'm not even entirely sure what "negative speed" means. Perhaps you mean a negative velocity? As in, moving in the opposite direction? If it did, that would still mean it's seeing a different v than earth observers are, and that the aliens would *know* that they are seeing a different v than earth.

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Old 23rd January 2021, 06:56 PM   #1783
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Originally Posted by Reformed Offlian View Post
No, I didn't. I can solve for c-HD by calculating E_observed/E_emitted, IOW, by calculating redshift. No assumptions about v required.
Ok.

Are you removing the peculiar velocity?


Quote:
Probably not. And if it did, that would still mean it's seeing a different v than earth observers are.
Only if it did, would it mean they see the photons different.

If the space ship doesn't see it all, it doesn't see the photon at a different speed as the other observer.

If my friend said they saw the Taj Mahal, I could say my friend told me about. It wouldn't be accurate to conclude that I saw it.

Somehow your aliens are able to measure the speeds of photons that are a distance from them. Is that within the realm of the laws of physics?
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Old 23rd January 2021, 07:27 PM   #1784
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Originally Posted by Mike Helland View Post
Ok.

Are you removing the peculiar velocity?
Your model just tells me that c-HD goes as E_observed/E_emitted. It doesn't have any additional terms for peculiar velocity. Provide those terms, and I'll put them in.

Quote:
Only if it did, would it mean they see the photons different.

If the space ship doesn't see it all, it doesn't see the photon at a different speed as the other observer.
If it doesn't see them at the same speed, then the actual speed must be different. One can eliminate a value with negative observations. You don't avoid the problem with word-play.

Quote:
If my friend said they saw the Taj Mahal, I could say my friend told me about. It wouldn't be accurate to conclude that I saw it.
No, but it would be accurate to say that you know what your friend saw, and that it's different from what you saw. One doesn't need to read minds to compare observations.

Quote:
Somehow your aliens are able to measure the speeds of photons that are a distance from them. Is that within the realm of the laws of physics?
The aliens are able to know what other observers see based on their reports. If you do a measurement and tell me what it is, then I know what your measurement was. And I can figure out whether it matches my measurement.

This is all made possible by your notion that photons can move at different speeds. The photons that somebody uses to report a gamma-ray burst to me can travel faster than the photons of the GRB itself. So I can find about them before the light from the GRB itself reaches me.

If you have a problem with that, than I suggest you rethink your own model.
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Old 23rd January 2021, 07:38 PM   #1785
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Originally Posted by Reformed Offlian View Post
Your model just tells me that c-HD goes as E_observed/E_emitted. It doesn't have any additional terms for peculiar velocity. Provide those terms, and I'll put them in.
The expanding universe doesn't provide them either.


Quote:
No, but it would be accurate to say that you know what your friend saw, and that it's different from what you saw.
But you didn't see anything.

You're treating a non-observation as an observation, and I don't think that's a good idea.

Quote:
The aliens are able to know what other observers see based on their reports. If you do a measurement and tell me what it is, then I know what your measurement was. And I can figure out whether it matches my measurement.
You didn't make measurement.
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Old 23rd January 2021, 07:41 PM   #1786
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I have a question about the null trajectory.

In an expanding universe, our light cone isn't exactly a cone, more like a champagne glass approaching Hubble's limit.

Here's a visual demonstration. Assuming that time=0 is now and this represents the future light cone of Earth.



On the image there is a red dot, where a future observer exists at the edge of our light cone.

They should have a Hubble volume around them I would think.

My question is does the area with the question mark (?) exist to the future observer?

Or does is their light cone limited?

Could we send signals to far away Hubble volumes this way?
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Old 23rd January 2021, 08:03 PM   #1787
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Originally Posted by Mike Helland View Post
The expanding universe doesn't provide them either.
As I mentioned earlier, it is possible to ascertain a peculiar velocity. The most obvious way would be noticing dipole anisotropies in the redshifts themselves. We don't see any that are significant (to >.01c)


Quote:
But you didn't see anything.You're treating a non-observation as an observation, and I don't think that's a good idea.
A negative observation isn't a non-observation. If I look in my room and don't see an elephant there, that is a negative result, but it is still an observation. And it is a different one from someone who reports seeing an elephant in my room.

If I don't look, that's a non-observation; however, in the thought experiment we are discussing, the aliens *are* looking. They just don't see anything. That isn't a non-observation; that is an observation with a negative result.

Quote:
You didn't make measurement.
Sure I did. I just got a negative result.
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Old 23rd January 2021, 08:08 PM   #1788
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Originally Posted by Reformed Offlian View Post
As I mentioned earlier, it is possible to ascertain a peculiar velocity. The most obvious way would be noticing dipole anisotropies in the redshifts themselves. We don't see any that are significant (to >.01c)
Wouldn't that apply to the redshifts either way then?


Quote:
If I don't look, that's a non-observation; however, in the thought experiment we are discussing, the aliens *are* looking. They just don't see anything. That isn't a non-observation; that is an observation with a negative result.
Um.

I'll take your word for it.
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Old 23rd January 2021, 08:16 PM   #1789
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Originally Posted by Mike Helland View Post
Wouldn't that apply to the redshifts either way then?
If by "either way" you mean "regardless of whether space is expanding", my answer would be: "it depends on whether redshifts are statistically isotropic in whatever alternative you have in mind." Since you're keeping the Hubble parameter, I suspect the answer would be yes.

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Old 23rd January 2021, 09:49 PM   #1790
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Ask Ethan: How Does The CMB Reveal The Hubble Constant?
A good explanation of how we measure the Hubble constant from the CMB.
The CMB is the same 2.7255 K in all directions except for fluctuations of about 0.003% (tens or hundreds of micro-degrees). The power spectrum of these fluctuations are fitted from the standard cosmological model. However, multiple sets of parameters fit. That is a "degeneracy" which other data reduces parameter sets to 67Ė68 km/s/Mpc for the Hubble constant and a universe with 5% normal matter, 27% dark matter and 68% dark energy.
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Old 23rd January 2021, 10:38 PM   #1791
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Originally Posted by Mike Helland View Post
Ok.

But the issue is the observers will have came to their own conclusions about D, which will differ.
No ****, Sherlock. And they will have contradictory answers. Which is why you need one reference frame to be special, and provide the right answer. I keep asking you for this frame, but you still don't even understand that your model needs it.

Quote:
How is it that these observers know the distance a single photon has traveled, but I don't know that as an observer in the physical world?
It's your model, why don't you figure that out?

And if your answer is to consult an odometer inside the photon, go sit in the corner and think about your terrible life choices.
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Old 23rd January 2021, 10:43 PM   #1792
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Originally Posted by Mike Helland View Post
In an expanding universe, our light cone isn't exactly a cone, more like a champagne glass approaching Hubble's limit.
It only looks that way if you use coordinates where comoving objects remain at fixed coordinates, even though the distance between them is getting larger. Light may look like it's slowing down (the curve is getting steeper), but it is not. Rather, each coordinate unit represents more and more space as time goes on.

Quote:
On the image there is a red dot, where a future observer exists at the edge of our light cone.

They should have a Hubble volume around them I would think.
Yes, they would, but you have drawn it incorrectly. The right side of their volume coincides with the right side of ours, it does not extend farther out. The left side will be mirrored, and will start at a steeper curve than ours. There is no region with a question mark.

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Could we send signals to far away Hubble volumes this way?
No.
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Old 23rd January 2021, 10:52 PM   #1793
Mike Helland
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Originally Posted by Ziggurat View Post
And if your answer is to consult an odometer inside the photon, go sit in the corner and think about your terrible life choices.
Ok.

I just did what you said.

There's a drumset in that corner.

I feel great.
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Old 23rd January 2021, 11:20 PM   #1794
Mike Helland
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Originally Posted by Ziggurat View Post
Yes, they would, but you have drawn it incorrectly. The right side of their volume coincides with the right side of ours, it does not extend farther out. The left side will be mirrored, and will start at a steeper curve than ours. There is no region with a question mark.
Something like this:



?

So this would illustrate the difference in geodesics in general relativity with Hubble's law as expanding space and Hubble's law as photon velocity.

As expanding space, the photon at the red dot still takes off in a light-light trajectory, because like you said space is represented as squished here.

A burst of light that we emit, and a burst of light that the red dot emits, will both travel alone the leftmost (*edit* I mean right) edge of the illustration. They're always following the same geodesic.

Do I have that right?

And as photon velocity (from previous post), the photon always is emitted a light-like, but then becomes time-like.

Last edited by Mike Helland; 23rd January 2021 at 11:25 PM. Reason: gr to hubbles law, also don't know left from right
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Old 24th January 2021, 07:17 AM   #1795
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Originally Posted by Mike Helland View Post
Something like this:

https://mikehelland.github.io/hubble...ghtcone_gr.png

?

So this would illustrate the difference in geodesics in general relativity with Hubble's law as expanding space and Hubble's law as photon velocity.

As expanding space, the photon at the red dot still takes off in a light-light trajectory, because like you said space is represented as squished here.

A burst of light that we emit, and a burst of light that the red dot emits, will both travel alone the leftmost (*edit* I mean right) edge of the illustration. They're always following the same geodesic.

Do I have that right?

And as photon velocity (from previous post), the photon always is emitted a light-like, but then becomes time-like.
I'm not an expert on drawing light cones, but I think what Zig means is that the left arms of each light cone will coincide (starting from the original diagram). So you'd need to rotate Red Dot's light cone clockwise. But I could be wrong. You haven't told us whether Red Dot is moving relative to the Earth.

Last edited by Reformed Offlian; 24th January 2021 at 07:19 AM.
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Old 24th January 2021, 09:15 AM   #1796
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Originally Posted by Mike Helland View Post
Understood.

Here's how I look at it.

Classical physics, relativity, and quantum mechanics all operate under the assumption that light can travel to infinity.

In 1929, after these things had been established the redshifts were discovered. No one had ever seen millions of light years away, and we found something new.

Light is supposed to go to infinity without losing energy. So the redshifts were taken as expansion.

That path has led us to some pretty incredible things, like the inflationary multiverse, and some head scratching results and anomalies.

Do you really believe that stuff?
Well, if anything physics in the 20th century taught is that intuition is a terrible guide to how the physical Universe works, particularly at large and small scales and in regions of strong gravity. Inflation seems incredible to you, but it makes testable predictions about what we observe today, tests which are compatible with what we see. Whereas, in order to get rid of inflation, you have proposed a hypothesis which is easily shown to be refuted by multiple observations and which, if it were to be correct, would require every major theory in physics to be rewritten. In effect, your personal incredulity has led you to propose something which cannot possibly be correct.

ETA: ...and your hypothesis doesn’t even solve the problems that inflation does, the flatness and horizon problems.

Last edited by hecd2; 24th January 2021 at 09:17 AM. Reason: ETA
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Old 24th January 2021, 09:26 AM   #1797
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Originally Posted by hecd2 View Post
Well, if anything physics in the 20th century taught is that intuition is a terrible guide to how the physical Universe works, particularly at large and small scales and in regions of strong gravity.
The difference is QM and GR are mind boggling precise and power the world around us.

No one can get anywhere anymore without GPS smartphones. That's QM and GR in everyone's hand everyday.


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Inflation seems incredible to you, but it makes testable predictions about what we observe today, tests which are compatible with what we see.
Excellent.

What prediction?

Quote:
ETA: ...and your hypothesis doesnít even solve the problems that inflation does, the flatness and horizon problems.
The horizon problem is why are different parts of the sky the same temp if there wasn't enough time.

The solution is that they add 990 billion years of expansion that occurs in less than a second.

That problem doesn't exist in my hypothesis.
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Old 24th January 2021, 09:39 AM   #1798
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Originally Posted by Mike Helland View Post
The horizon problem is why are different parts of the sky the same temp if there wasn't enough time.

The solution is that they add 990 billion years of expansion that occurs in less than a second.

That problem doesn't exist in my hypothesis.
Yes it does. Your hypothesis still has particle horizons.
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Old 24th January 2021, 09:42 AM   #1799
Mike Helland
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Originally Posted by Reformed Offlian View Post
Yes it does. Your hypothesis still has particle horizons.
For a single particle.

I could send light signals to the edge of the observable universe, were a receiver could re-transmit them with fresh photons.

Multiple hubble volumes can be causally connected this way.
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Old 24th January 2021, 10:09 AM   #1800
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Originally Posted by Mike Helland View Post
The difference is QM and GR are mind boggling precise and power the world around us.

No one can get anywhere anymore without GPS smartphones. That's QM and GR in everyone's hand everyday.
And yet you are proposing a hypothesis that requires you to throw these under a bus. Ironic?
Quote:
Excellent.

What prediction?
Well, I have mentioned a couple before. Inflation predicts a homogeneous, isotropic universe. It predicts that the geometry of the universe should be flat or nearly flat. It predicts structure on large scales. It predicts that the structure will be adiabatic and almost but not quite scale invariant. It predicts that anisotropies in the CMB should be Gaussian.

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The horizon problem is why are different parts of the sky the same temp if there wasn't enough time
.Not just the same temperature, but the same density of matter and geometry on the largest scales.
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That problem doesn't exist in my hypothesis.
Of course it does. As does the flatness problem, since a non-expanding universe with no dark energy is unstable and cannot exist.
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