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James Webb Space Telescope finds evidence for alternate theory of gravity

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355 points jchanimal | 4 comments | 16 Nov 24 18:33 UTC | HN request time: 0.001s | source
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samsartor ◴[16 Nov 24 20:21 UTC] No.42158987[source]▶
My hangup with MOND is still general relativity. We know for a fact that gravity is _not_ Newtonian, that the inverse square law does not hold. Any model of gravity based on an inverse law is simply wrong.

Another comment linked to https://tritonstation.com/new-blog-page/, which is an excellent read. It makes the case that GR has never been tested at low accelerations, that is might be wrong. But we know for a fact MOND is wrong at high accelerations. Unless your theory can cover both, I don't see how it can be pitched as an improvement to GR.

Edit: this sounds a bit hostile. to be clear, I think modified gravity is absolutely worth researching. but it isn't a silver bullet

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1. MattPalmer1086 ◴[16 Nov 24 20:28 UTC] No.42159034[source]▶
MOND isn't pitched as an improvement to GR. It was always a Newtonian theory - it's in its name!

There are relativistic versions of MOND, for example, TeVeS [1], but they all still have some problems.

[1] https://en.m.wikipedia.org/wiki/Tensor%E2%80%93vector%E2%80%...

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2. samsartor ◴[16 Nov 24 20:37 UTC] No.42159103[source]▶
TeVeS is definitely interesting, but it still has problems like you said. AFAICT gravitational wave observations are particularly bad for TeVeS theories. TeVeS isn't dead, but if dark matter theories are criticized for being patched up post-hoc, that standard should also apply to modified gravity.
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3. gliptic ◴[16 Nov 24 20:54 UTC] No.42159228[source]▶
The weirdest thing about TeVeS IMO is that it adds additional fields that warp spacetime, so how is it not a dark matter theory?
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4. MathMonkeyMan ◴[16 Nov 24 21:41 UTC] No.42159598{3}[source]▶
For the fields to be considered particles, they have to be freely propagating in space. TeVeS adds a vector field, a scalar field, and some lagrange fields that are part of their coupling. The degrees of freedom aren't consistent with one or more particles.