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The James Webb Space Telescope is finding too many early galaxies

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Re: The James Webb Space Telescope is finding too many early galaxies

#501

Post by narag »

mr_mitm wrote: post #475
narag wrote: post #302

Earlier quoted context omitted.

The funny thing is that since we've been observing the universe for so little time, and we're so small, most of the evidence for the big bang and expansion is not direct , but a chain of deductions. I mean that we can't observe the expansion because we can't really triangulate at galactic scale. If there is another reason the light from distant galaxies turn to red, kind of a long-distance light fatigue, we couldn't…

> The reason I always heard that would be a confirmation, because it comes from a different causal path, was precisely the different composition of old galaxies And you never heard of the CMB? That's generally considered the "smoking gun" evidence for the big bang.

That's attributed to Big Bang because most people believe there was a Big Bang. Maybe it comes from another phenomenon. Or maybe they're right.

Re: The James Webb Space Telescope is finding too many early galaxies

#502

Post by dTal »

saberdancer wrote: post #437
nickelpro wrote: post #383

Earlier quoted context omitted.

If MOND completely described observable phenomenon it would supplant dark matter, but it doesn't. MOND still requires dark matter, just less of it. Or, to quote Milgrom, "some standard matter in some form that has not been detected"[1]. Which, IMHO, is nearly isomorphic to DM as far as statements go. So until we figure out what the missing mass is, MOND is widely viewed as an unnecessary complication. There is missin…

Problem that I see with dark matter is that it is unfalsifiable. If you can have arbitrary amounts of dark matter in arbitrary positions - how can you falsify that?

It's not as if dark matter doesn't follow any rules at all - hypothetically, it obeys gravity like any other matter. So you can't have arbitrary amounts in arbitrary positions - you have to explain what attracted the dark matter to that position.

Re: The James Webb Space Telescope is finding too many early galaxies

#503

Post by cevn »

Tuna-Fish wrote: post #22
cevn wrote: post #4

Can someone explain to me what would be behind the galaxies if we could see it, to the point of 0 seconds after the big bang? Black, white, is it even possible?

We can't see down to 0 seconds, because very soon after the big bang, the universe was filled with dense, extremely hot, opaque plasma. The closest we can get is the "recombination epoch" [0], which is roughly 370 000 years after the big bang, when, because of universal expansion, the plasma got cold enough for neutral hydrogen to start forming, at which point the universe became transparent. As protons gain electron…

Fascinating... so we see the CMB, got it. I wonder if someone could take what seems like the random pattern of the CMB and reverse it into some vision of the BB..

Re: The James Webb Space Telescope is finding too many early galaxies

#504

Post by bmitc »

moffkalast wrote: post #495
jquery wrote: post #377

Earlier quoted context omitted.

It seems to me, as a layperson, if MOND was hypothesized first, it would be the dominant theory. It’s so elegant and simple with so much explanatory power. However, because it was hypothesized much later, the fact it matches past predictions is given no weight, despite its simplicity. I think this is a bit of a mistake. I believe that simplicity itself is evidence. Dark matter theory is starting to feel like the epic…

I was pretty convinced that dark matter is made up nonsense and that RelMOND is probably correct, but then I learned of the Bullet cluster. https://en.wikipedia.org/wiki/Bullet_Cluster#Significance_to... Two clusters collided, with most of the observable objects being just past the middle point right now, however most of the mass seems have already shot way out to the edges, as if it passed right through everything.…

> however most of the mass seems have already shot way out to the edges, as if it passed right through everything. It's pretty hard to explain with anything else other than that there's something there that has mass yet can't interact with anything else that passed through everything when the collision happened.

It is my understanding that dark matter does interact gravitationally, so I am confused by this.

Re: The James Webb Space Telescope is finding too many early galaxies

#505

Post by bmitc »

Beldin wrote: post #484
ndsipa_pomu wrote: post #455

Earlier quoted context omitted.

However, there is plenty of evidence to suggest that it does exist. The distribution of dark matter being uneven is evidence that something functioning like dark matter has to exist as MOND doesn't easily replicate that. Colliding galaxy clusters show a distribution of matter that differs from the distribution of visible matter, so the simplest explanation is that there is invisible matter that reacts gravitationally…

The simplest explanation is that there is regular matter which we fail to detect. Not weird, given the huge distances involved - there almost assuredly is mass that we didn't detect (e.g. planets). The point where fairy matter comes in, is that we can guess how bad we could be at not detecting matter. Basically, regular matter that we didn't observe can't explain everything - we would've observed it otherwise.

> The simplest explanation is that there is regular matter which we fail to detect. Not weird, given the huge distances involved - there almost assuredly is mass that we didn't detect (e.g. planets).

What is the difference between that and dark matter?

> there almost assuredly is mass that we didn't detect (e.g. planets).

Don’t planets give off light and thus contribute to the distribution of light observed?

Re: The James Webb Space Telescope is finding too many early galaxies

#506

Post by __alexs »

medstrom wrote: post #498
__alexs wrote: post #470

Earlier quoted context omitted.

Ice isn't slippery, water is. If anything I'd say ice is actually pretty sticky. A very cold ice cube will easily stick to your skin.

That's just because your skin has water molecules that freeze on contact with the ice cube. If you use tongs to put an ice cube on your desk, it doesn't stick at all, right? And the friction is very low so it's easy to kick away -- things like a leather wallet stick much better to your desk.

I've not tried it but intuitively I'd expect it to slide about as well as other very hard things of the same shape.

Re: The James Webb Space Telescope is finding too many early galaxies

#507

Post by lukas099 »

JumpCrisscross wrote: post #337
emptybits wrote: post #272

Earlier quoted context omitted.

I had to look that up. Here's research[1][2] from 2019 about "why ice is so slippery", including some of the apparent surprises. I dunno. I'm not a physicist so some of the surprises seem like very minor things to me. Spoiler: According to this research, ice is slippery because of a thin layer of water. (As we expected, no?) But the water layer is 1) thinner than expected, 2) more viscous than expected, and 3) contai…

> contains bits of ice which help make it extra slippery Wait, why would bits of ice make it extra slippery if it's the water that makes ice slippery?

Maybe the ice molecules move through the water with less resistance, since the ice molecules are already 'tied up' in a lattice structure and therefore do not form as strong of hydrogen bonds with the neighboring water molecules.

Re: The James Webb Space Telescope is finding too many early galaxies

#508

Post by lukas099 »

__alexs wrote: post #506
medstrom wrote: post #498

Earlier quoted context omitted.

That's just because your skin has water molecules that freeze on contact with the ice cube. If you use tongs to put an ice cube on your desk, it doesn't stick at all, right? And the friction is very low so it's easy to kick away -- things like a leather wallet stick much better to your desk.

I've not tried it but intuitively I'd expect it to slide about as well as other very hard things of the same shape.

I've dropped ice cubes on the floor before and they definitely slide a lot more than most objects of the same shape.

Re: The James Webb Space Telescope is finding too many early galaxies

#509

Post by [deleted] »

moloch-hai wrote: post #481
eru wrote: post #385

Earlier quoted context omitted.

Eh, 'Citation needed.' was my admittedly somewhat snarky way of calling bullshit. Most any scientist will happily babble all about the stuff they don't know yet in their discipline, because that's exactly where the excitement lies for them.

Some do. Many don't. Much of Wikipedia is "curated" by retired professors carefully scrubbing mention of anything new that makes their graduate thesis look ill-conceived.

[deleted]

Re: The James Webb Space Telescope is finding too many early galaxies

#510

Post by gala8y »

astroH wrote: post #460

I have to say, this article is exceptionally disappointing. As someone who works in this space, there are numerous misleading depictions about the state of the field. Almost any respectable simulation shows that disk galaxies are widely present at very early times. This is simply an argument of angular momentum conservation and these rotational states are simply more transient at early times compared to the local Uni…

Honestly, thank you very much for this comment. As a lay person, I very often fall into taking such news as solid, as am kind of hoping for some great breakthroughs in cosmology (broadly speaking). Thanks for providing details. "One particular problem is correlated hot pixels" has a nice, cooling effect on me and I get the idea that it is an unsolved issue (kind of get it). Same with "experts only believe those with spectroscopic confirmation" - fair enough. An antidote for getting fooled in this way by such articles (or YT video beating some popular notions over and over) is to read core material (like books) and seek some actual lectures, I think. That's a pity you can't skim some topic and have it right. You just can't and it only fills you with fake knowledge.
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