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James Webb Space Telescope reveals that most galaxies rotate clockwise

smithsonianmag.com

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Re: James Webb Space Telescope reveals that most galaxies rotate clockwise

#281

Post by andrewaylett »

xeornet wrote: post #194
andrewaylett wrote: post #22

Earlier quoted context omitted.

Clockwise relative to our viewpoint, while we would expect that we'd see an equal number rotating in either direction no matter which way we looked or where we were looking from.

Sorry if it's a dumb question, by why would we expect an equal number? Doesn't that assume that we consider ourselves at the centre of our observable universe?

If the orientation of galaxies is totally random, we would expect no bias in orientation. If you look at an arbitrary galaxy that's face on to us, it could be rotating either way. And we had no reason to set our prior at anything other than 0.5: why would one direction be more common than the other?

But we observe a bias. Now, that could just be chance — but it's more likely that we've missed something somewhere so our assumption was wrong. One specific possibility is that the universe has an intrinsic spin, which might be because (per the article) we're inside the event horizon of a black hole which is spinning.

Also, yes: we are at the centre of our observable universe.

Re: James Webb Space Telescope reveals that most galaxies rotate clockwise

#282

Post by nottorp »

raattgift wrote: post #279
nottorp wrote: post #268

So do the galaxies rotate clockwise, or did we make clocks that rotate in the direction the galaxies choose? :)

Sundials are really really cool, and the shadow sweeps in the clockwise direction at mid-latitudes in the northern hemisphere, but https://en.wikipedia.org/wiki/Sundial#In_the_Southern_Hemisp... So "clockwise" is because the Earth's axis of rotation about itself is not too far from perpendicular to its orbital plane of rotation around the sun, and because the Earth rotates counter-clockwise from the perspective of so…

Heh I was joking but you can trust HN to have someone come up with a comprehensive explanation for anything :)

Re: James Webb Space Telescope reveals that most galaxies rotate clockwise

#283

Post by soulofmischief »

thaumasiotes wrote: post #275
soulofmischief wrote: post #238

Earlier quoted context omitted.

My point is that it's not much helpful to say, "galaxies spin a certain way because the universe spins", because it shifts the problem without actually answering the "why". "Turtles all the way down" is a saying about such infinite regress. https://en.wikipedia.org/wiki/Turtles_all_the_way_down And yes, I'm familiar with Dawkins' famous retort when someone asked how magnets repel things.

> And yes, I'm familiar with Dawkins' famous retort when someone asked how magnets repel things. I'm not. I was unable to substantiate that anyone named Dawkins, Richard or otherwise, made or is popularly associated with a comment about magnets. What was the retort?

I deeply apologize, it was late and I mixed up my Richards. :)

https://youtube.com/watch?v=36GT2zI8lVA

Re: James Webb Space Telescope reveals that most galaxies rotate clockwise

#284

Post by pal9000i »

antonvs wrote: post #240
nabla9 wrote: post #229

> The same solo author (a computer scientist) has made many similar claims based on a variety of datasets. Often coming to completely contradictory conclusions. Some of these claims have been followed up by astronomers, who found errors in his analysis and poor statistical tests. His claims have been discussed in this sub before. Independent studied have found no significant evidence of anisotropy. https://academic.o…

The author is also a proponent of tired light theory, which has been thoroughly refuted.

I was prepared to be mindblown. He lost all credibility to me

Re: James Webb Space Telescope reveals that most galaxies rotate clockwise

#286

Post by jfengel »

drusenko wrote: post #269
jfengel wrote: post #259

Earlier quoted context omitted.

The trick is that bigger black holes are less dense. Supermassive black holes can have the density of water. If the universe is gravitationally closed, it would have the density of... well, just look up at night. (Actually much less than that; you see more stars because you're inside a galaxy.) The density makes the scale recursion less mysterious.

That’s interesting! When you are referring to density, are you referring to average density within the event horizon? Isn’t most (effectively all) matter concentrated in the singularity? Would love to hear you elaborate on this thought further.

We can't really talk about what's inside a black hole. From outside, it has a volume and a mass, and that's all there is to know.

We can say that any particle inside the horizon is inevitably headed to the center. (That's why we can't say any more: no other information can escape.) That does lead to a problem in that all of the mass would be concentrated at a single point at the center, whose density is division-by-zero.

But I wouldn't put too much weight on that. We already know from quantum mechanics that there isn't really any such thing as a "point". The math is still a problem, but the solution almost certainly lies in that direction.

Re: James Webb Space Telescope reveals that most galaxies rotate clockwise

#287

Post by MichaelZuo »

namaria wrote: post #272
MichaelZuo wrote: post #227

Earlier quoted context omitted.

That doesn’t make sense, they can’t be assumed to have behaved like ideal gasses, thus turbulence alone can cause significant uncertainties. Let alone all other possibilities combined.

I don't get it, why did you ask for clarifications about why this was not expected if you're just going to be adamant it should have been expected? Is it really your honest position that everyone has been doing cosmology wrong and you would have known better?

I didn’t ask for clarifications… I asked how it followed…

Are you sure you understood the comments completely?

It’s my honest opinion that anyone assuming away phenomena like turbulence, without credible proof, cannot be relied upon to have accurate insights.

So yes whenever I do have better insights, than by definition that’s more than 100% of the population who do not.

Re: James Webb Space Telescope reveals that most galaxies rotate clockwise

#288

Post by SkyBelow »

vlovich123 wrote: post #265
SkyBelow wrote: post #204

Earlier quoted context omitted.

Is it an illusory artifact or is it all that exists? If it can't be observed, it can't be tested, it can't be verified in any way or ever interacted with, then isn't it just an instances of Russell's Teapot and thus does not exist? What does it mean for science if existence isn't a binary property or one that we set as a truth yet is entirely untestable?

We definitely have reason to believe that there’s universe outside the observable universe. The CMB uniformity suggests that that’s the case as do our theoretical models. The mere fact that two observers have different observable universes indicates it is indeed an illusory artifact. Just because something is untestable today doesn’t mean it will be for all time. However, the untestability problem has started to cree…

>Just because something is untestable today doesn’t mean it will be for all time.

This is generally true, but such ideas are kept outside the realm of science until they are. In this case specifically, all our knowledge points to this remaining untestable as it would require FTL travel which is on par with violating conservation of energy or time travel. It even allows solving the halting problem (Turing machine in timeloop until it halts, you outside of the timeloop can then check if the Turing machine in the timeloop ever left it).

It is entirely possible that there are things which are true which science cannot verify because of the underlying philosophy by which science operates. Things that exist outside of the observable universe, if FTL travel is truly impossible, would fall outside the realm of science.

>The mere fact that two observers have different observable universes indicates it is indeed an illusory artifact.

Do they? The nature of the observable universe is that, if you can communicate with someone else, any information they can receive and pass on to you is part of your observable universe as all information travels at the speed of light or slower. If they can receive information and cannot pass it on to you, they are not part of your observable universe any longer and no longer exist (exception if FTL interactions are discovered). Thus the only observers that exist in a way you can interact with, can make any testable hypothesis concerning, and thus can be considered by science, are observers in your observable universe.

Re: James Webb Space Telescope reveals that most galaxies rotate clockwise

#289

Post by lolc »

eightysixfour wrote: post #175
nashashmi wrote: post #158

Earlier quoted context omitted.

It can be directly sucked into the center. A spiral implies a lateral movement plus a centripetal force

Right, I guess what I am saying is if it didn't spiral, it wouldn't be a galaxy for "long." It would just be a super massive black hole.

The trick to having a galaxy is for mass to fall towards the black hole and miss it all the time.

Re: James Webb Space Telescope reveals that most galaxies rotate clockwise

#290

Post by antonvs »

EGreg wrote: post #263
ajross wrote: post #225

Earlier quoted context omitted.

Yes, that's it exactly. There's a net asymmetry in the distribution of galaxy axes. "Clockwise" by itself is a relative term. This seems to be the paper in question: https://academic.oup.com/mnras/article/538/1/76/8019798 That said: I'd wait a bit here. This is a single-author paper by a non-astronomer (he's a CS professor). The sample size seems small (N=263), and the measurement coarse (he's just bucketing galaxies…

Look, if the visible universe is expanding, as we think it is, that is already a direction. Viewing galaxies “from the other side” is not the same in an expanding bubble. It’s like being surprised that many things are redshifted no matter where you look. As for rotations — you could perhaps have some local coriolis force. The visible universe is redshifted and galaxies are getting further and further away. So jumping…

> Look, if the visible universe is expanding, as we think it is, that is already a direction.

Could you point in that direction?

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