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Can rotation solve the Hubble Puzzle?

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Re: Can rotation solve the Hubble Puzzle?

#41

Post by griffzhowl »

kstrauser wrote: post #27
lambdaone wrote: post #16

Earlier quoted context omitted.

Below the Planck distance, "closer" ceases to be a meaningful concept. Similarly, distances larger than the size of the observable universe may also be meaningless.

Why is that? I've heard this before but don't understand what it actually implies. Like, why can't 2 things meaningfully be half a Planck distance apart?

It's just that it's physically impossible to measure such small scales. To probe a smaller scale you have to put more energy into a volume (roughly, because you have to force particles closer together), and at some point you have to put so much energy into such a small volume that it becomes a black hole, then any more energy you put in will just make the black hole bigger. So there seems to be a fundamental limit to how short a scale we can probe, and therefore we can't give a physical meaning to smaller scales. Nima Arkani-Hamed talks about htis in a few lectures online.

This is just according to our current theories, and you don't need any speculative ideas about granularity of space. Mathematically, there's no problem in considering arbitrarily small length scales, because current theories are based on continuous space and time dimensions, but since we can't give physical meaning to small length scales, that's a clue that a more fundamental theory will somehow not be based on continuous space and time

Re: Can rotation solve the Hubble Puzzle?

#42

Post by roarkeful »

bostonwalker wrote: post #6

I seem to recall there was an article posted here recently which noted that galaxies have a preferred direction of rotation. Seems like the universe itself rotating could be a reason why?

The universe being a giant toilet in the process of flushing is delightfully Doug Adams inspired.

Re: Can rotation solve the Hubble Puzzle?

#43

Post by pmontra »

BigParm wrote: post #35
est31 wrote: post #4

> All objects within our universe rotate, including planets, stars, solar systems, galaxies, and galaxy clusters. Moreover, black holes, spherically symmetric objects with horizons, display near maximal rotation as presented by Daly (2019). The idea that everything revolves [...] naturally extends to the whole universe, as hinted by recent claims of anisotropic Hubble expansion in X-ray observations by Migkas et al.…

If spacetime rotates, does that imply there being a centre of the universe?

Wouldn't the center be the Big Bang and the 3D Universe at the current time (if Relativity lets me write about a current time) be the 3D surface of the 4D sphere (or spheroid) that the Big Bang is creating by keeping to expand?

Re: Can rotation solve the Hubble Puzzle?

#45

Post by WhitneyLand »

“We show that a Gödel inspired slowly rotating dark-fluid variant of the concordance model resolves this tension…”

Gödel wait what? I thought of him as “only” the logician who killed Hiblert’s dreams and caused people to question the very foundations of mathematics.

Dude then took up physics as a hobby and trolled Einstein by discovering closed time-like curves?

Re: Can rotation solve the Hubble Puzzle?

#47

Post by jinwoo68 »

Universe is called universe because it is the only one. Everything that exists should be part of the universe. When we say the universe rotates, what does it mean? Rotate relative to what? Does it mean that there's a larger "universe" that contains ours?

Re: Can rotation solve the Hubble Puzzle?

#48

Post by TheRealPomax »

lumost wrote: post #8
hoseja wrote: post #2

Wait did nobody seriously consider rotation yet? Everything is rotating. Angular momentum is conserved.

Rotation implies a great many observables and properties of the universe. There would be a cosmic axis, which implies a cosmic center and a cosmic north. Both concepts that are problematic in an infinite universe. If the universe is in fact inside of a black hole of a different universe - some of these problems go away as the Hubble volume would be the finite boundary of the universe.

Except why would there only be one axis?

Re: Can rotation solve the Hubble Puzzle?

#49

Post by AnimalMuppet »

voidUpdate wrote: post #34
ben_w wrote: post #33

Earlier quoted context omitted.

It's (mathematically) allowed for it to have always been infinite, and still grow. If you take the number like and apply f(x) = 2x, it was infinite before and after.

yes but if x is finite, any f(x) will still be finite. So the universe has either always been finite, or always been infinite, and given that it started out being very small in a big bang, it would imply the former

f(x) = tan(x)

f(x) = 1/(1-x)

So if x is finite, f(x) can still be infinite.

Re: Can rotation solve the Hubble Puzzle?

#50

Post by layer8 »

BigParm wrote: post #35
est31 wrote: post #4

> All objects within our universe rotate, including planets, stars, solar systems, galaxies, and galaxy clusters. Moreover, black holes, spherically symmetric objects with horizons, display near maximal rotation as presented by Daly (2019). The idea that everything revolves [...] naturally extends to the whole universe, as hinted by recent claims of anisotropic Hubble expansion in X-ray observations by Migkas et al.…

If spacetime rotates, does that imply there being a centre of the universe?

If the universe is the interior of a black hole, one would assume so.
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