[oneshtein]

These numbers means that nothing can travel at FTL speed except this galaxy. It travelled 20Bly in 13By at the speed of 1.5 c. Extraordinary claim requires extraordinary evidence. Where is the source of energy for this FTL galaxy? Why this galaxy is not ripped apart into ball of gluon plasma?

Echo requires something to reflect of. Moreover, echo will be an order(s) of magnitude weaker and will have a stamp of the reflective surface on it properties.

[ben_w]

> These numbers means that nothing can travel at FTL speed except this galaxy

Nothing including this galaxy can beat light locally.

Look up the balloon (or raisin bread) analogy.

> echo will be an order(s) of magnitude weaker and will have a stamp of the reflective surface on it properties.

It does. That's in the CMB.

[oneshtein]

> Look up the balloon (or raisin bread) analogy.

In bread analogy, sugar is the source of energy and CO2. In balloon analogy, new air is added to balloon (with lot of turbulence). What is added to our Universe, which causes the inflation? Where we can see it?

In case of Steady Universe model, light just changes it's properties over time, for example, because gravitational waves are stretching photons and photon beams. Gravitational waves are produced by massive objects, which are orbiting each other.

[ben_w]

> What is added to our Universe, which causes the inflation?

It's a free parameter in the equations, just like the initial value for the energy in the space or the baryon number.

Or the number of space-like and time-like dimensions.

Or their inherent topology.

Not that it matters, as the point of what I suggested is that it's an analogy for all objects within the space observing the same relationship, and the implications thereof.

> Where we can see it?

In the relationship between distance and redshift. More distant objects move away faster, the further away the faster they move on average, and that relationship best matches "accelerated expansion" than any other model.

Or, more locally, it's (perhaps by coincidence) about the right level to explain the moon's orbit slowly getting bigger.

> In case of Steady Universe model, light just changes it's properties over time, for example, because gravitational waves are stretching photons and photon beams. Gravitational waves are produced by massive objects, which are orbiting each other.

Great!

Unfortunately for you, those gravitational waves can't act anything like the ones predicted by GR which we've actually observed, because those are far too weak (or spacetime too 'stiff', IIRC).

GR has known weaknesses, to be sure, but they're all annoying beyond any observations we've been able to make, and people really are looking as it's considered both important and prestigious to find a way to tie it and quantum physics together properly.

In the meanwhile, the same equations for GR describe the (just about) detectable gravitational influence your body has, and the various demonstrations of gravity influencing the flow of time and path of nearby light.

IIRC, the best atomic clocks are just about at the level where an extra 100kg sitting next to them can change the last digit relative to another otherwise identical clock, but I'm not sure how long you have to sit there.

They're definitely good enough for it to matter which floor of a building you put them on.

[oneshtein]

> Unfortunately for you, those gravitational waves can't act anything like the ones predicted by GR which we've actually observed, because those are far too weak (or spacetime too 'stiff', IIRC).

Let's play with numbers. Two kinds of gravitational waves are claimed to be observed: 1) HF waves by LIGO/Virgo and 2) LF ones by NANOgrav[1].

I assume, that the meter is defined as c1s/299792458 in steady vacuum*. Same for the second. I assume, that speed of light can go down only, in other words, speed of light cannot be higher than c.

Gravitational wave background strain amplitude calculated to be ~ 2.4E-15 y-1. For simplification, I assume average slowdown (stretching) of light to be 1E-15 per year.

LF gravitational waves are quite powerful, with strain amplitude 2.4E-15 y-1, but their low frequency does almost no impact to the wave length of light. In 1 billion of years, wave length will be enlarged by up to 1,0000024.

HF gravitational waves are much weaker, say 1E-21, but their high frequency, say 20kHz, may increase wave length up to 1.88, which is much closer to expected Red Shift of 7.

[1]: https://iopscience.iop.org/article/10.3847/2041-8213/acdac6

[ben_w]

24 kHz gravitational waves are made by…

a pair of objects orbiting 24 thousand times per second.

This happens when black holes or neutron stars merge and that's it; this means you don't have enough of them to do what you're claiming, not even if I trusted what looks suspiciously like you blindly asserting without evidence how much they should alter wavelengths.

The effect of gravitational waves is barely anything even on the LIGO detector, and they need to use a squeezed quantum state to even notice because it's much smaller than the wavelength of the light even over the length of the entire beam-line.

Also, gravitational waves don't redshift the photons, they change the length of the path the photons take.

-

And as LIGO, NANOGrav etc., are relying on a prediction of the exact same GR equations that also lead to the big bang etc., you trying to shoehorn that in is roughly analogous to a Young-Earth Creationist talking about carbon dating.

[oneshtein]

Or by 24 thousand pairs orbiting 1 time per second, or by 24000*365*24*60*60 pairs orbiting 1 time per year.

> Also, gravitational waves don't redshift the photons, they change the length of the path the photons take.

Yep, more length to travel - larger wave length. :-/

> And as LIGO, NANOGrav etc., are relying on a prediction of the exact same GR equations that also lead to the big bang etc

I had a discussion about that recently. I have no power to repeat the discussion. You can find it in my comment history.