[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.

[ben_w]

> Or by 24 thousand pairs orbiting 1 time per second,

no, and for the same reason you can't use the output of a quarter million 2.45 Ghz microwave oven magnetrons to produce monochromic teal light (612500 Ghz).

The maths is basically equivalent for EM and gravity waves, except for the constants.

Well, that and the fact it's changing the space-time through which the waves themselves propagate, but the effect is usually small enough to be barely detectable even when you want to.

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

no, same wavelength, going further on one half of the cycle, then not as far on the other half of the cycle. Same wavelength within the space, it's the space itself which changes.

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

TBH, that would be a colossal waste of my time. I'm only even bothering to reply to this this now because discussion is supposed to be helpful while I learn things.

[oneshtein]

> no, and for the same reason you can't use the output of a quarter million 2.45 Ghz microwave oven magnetrons to produce monochromic teal light (612500 Ghz).

Why we need monochromatic light? Gravitational wave background is just noise. A lot of orbiting objects in a galaxy will produce steady noise, due to interference. It's easy to check just by putting a bunch of wave generators with different frequencies in a same pond, and then move. Interference between waves will create noise with higher frequencies than original.

Even small effects are producing significant results over large periods of time. 1 billion years is 31.5E15 seconds.

If we integrate over all frequencies of gravitation noise floor, then we may have a number, which will explain a part of red shift.

More over, gravitational noise is important for Pilot Wave theory, because it may explain the source of energy for the pilot wave.

> no, same wavelength, going further on one half of the cycle, then not as far on the other half of the cycle. Same wavelength within the space, it's the space itself which changes.

It implies FTL speed at the second half of the cycle, which is impossible. If wavelength of light will be enlarged, then it will stay enlarged, because light traveling at c, so c-delta is possible, but c+delta is not.

> TBH, that would be a colossal waste of my time. I'm only even bothering to reply to this this now because discussion is supposed to be helpful while I learn things.

I have the same filling. I only reply because my pleasure to talk with you overcomes the inconvenience of Hacker News.

Maybe we should switch to email, or to a wiki with a proper set of tools for scientific discussion.