Maybe, just maybe the Universe is infinite and eternal? and the big bang never happened?
The James Webb Space Telescope is finding too many early galaxies
361–370 of 547 posts
Re: The James Webb Space Telescope is finding too many early galaxies
#362The Universe AI is trolling us.
Re: The James Webb Space Telescope is finding too many early galaxies
#363Earlier quoted context omitted.
Without getting into lots of detail, this is basically correct. It's why we talk about the observable universe. There's lots of stuff we can't see because the light from it won't reach us.
> because the light from it won't reach us. This is one of the most interesting aspects to the universe. It's not, "because the light from it hasn't reached us yet but is on the way and will get here eventually." Rather it's that the rate of expansion of the universe is accelerating, so that we're moving away from parts of it faster than its light can cover the distance to us. It will never reach us. That's mindboggl…
Something that’s even more mind boggling than that, at least to me is that the universe is still within the first few seconds (or minutes) of its life in terms of relative time we can comprehend. As stars collapse and black holes consume everything, the universe will spend 99% of its life in complete desolate darkness. An endless sea of black holes for billions and billions of years. The fact that we exist, in the split second that life can exist is unimaginable.
Re: The James Webb Space Telescope is finding too many early galaxies
#364Earlier quoted context omitted.
At this point in the thread, I'm wondering if we do a disservice to physics students by making it appear we have it all figured out.
I don't think I've ever, out of all my physics classes up to grad seminars, been given the impression we have everything figured out. In fact, it was hammered into us that all we have are "effective" theories, at least when it comes to high energy physics, and that's not even talking about grand unification (electroweak + strong force unification), let alone Theory of Everything (electroweak + strong + gravity).
Maybe not where you studied, or at the level you studied, but in upper division undergrad physics at a top tier California school I definitely was given the impression that I should just crunch the numbers and not think too much about how it might be working.
Re: The James Webb Space Telescope is finding too many early galaxies
#365Earlier quoted context omitted.
My favourite example of the intractabilities of some theories is that magnetohydronamics apparently can't predict the formation of streamer jets when you put your finger on a kid's plasma ball – i.e. the main point of the toy is beyond the most advanced theory that lies behind NIF, JET, ITER, etc...
Magnetohydrodynamics is, specifically, the "easy part" carved out of plasma fluid dynamics. It is inadequate to almost all applications, with only rare, precious exceptions, mostly manufactured. Devices that rely on plasma fluid dynamics to work are carefully designed to keep the plasma in the domain where MHD can be used to model them. Astrophysicists, as a rule, hate to be obliged to consider phenomena that involve…
Is plasma fluid dynamics the most important hated obligation of astrophysicists?
Re: The James Webb Space Telescope is finding too many early galaxies
#366This was predicted by astronomer Stacy McGaugh on his super interesting blog as a natural consequence of modified Newtonian dynamics ( https://tritonstation.com/2022/01/03/what-jwst-will-see/ ). McGaugh came to support MOND over dark matter reluctantly for just such reasons—MOND routinely predicts things in advance that dark matter struggles to justify ex post facto, usually by adding additional moving parts to the m…
Any publications indicate whether Refracted Gravity (RG) predicts the same thing?
RG has always fascinated me, since it neatly explains flat rotation curves[1] without messing up the equations for gravity too much. If some refractory effect (TBD) causes gravity to bend toward mass concentrations, then this effectively "confines" gravity into a plane. Then the propagation law becomes 1/r rather than 1/r^2.
In effect it becomes a galactic analog of the SOFAR layer in the ocean.[2]
Intuitively the "self feeding" effect on disk formation should accelerate the process, but I'd be interested to see a full treatment.
[1] https://www.aanda.org/articles/aa/pdf/2020/05/aa35950-19.pdf
Re: The James Webb Space Telescope is finding too many early galaxies
#367Earlier quoted context omitted.
What I'm going to ask you is completely dumb, but keep in mind I don't know much of physics. If my understanding is correct, when mass gets dense enough inside, a star you have a black hole, that would be like a hole in the fabric of space time. Ok, we have black holes in the contemporary universe. So how was the primordial universe a ball of dense, extremely hot, opaque plasma without becoming a huge black hole?
Because the primordial universe was in a state of extremely fast expansion, while black holes today exist in space-time that is almost exactly flat. In fact, if the universe really started from a singularity, the expansion was infinitely fast for an instant.
To hedge the next question then: Why was the universe expanding so quickly?
It seems that the expansion must have been so fast that it was going faster than light speed, right? Otherwise the very dense universe must have gone black-hole.
Re: The James Webb Space Telescope is finding too many early galaxies
#368Earlier quoted context omitted.
Magnetohydrodynamics is, specifically, the "easy part" carved out of plasma fluid dynamics. It is inadequate to almost all applications, with only rare, precious exceptions, mostly manufactured. Devices that rely on plasma fluid dynamics to work are carefully designed to keep the plasma in the domain where MHD can be used to model them. Astrophysicists, as a rule, hate to be obliged to consider phenomena that involve…
Is plasma fluid dynamics the most important hated obligation of astrophysicists?
I think most consider it "somebody else's problem". I know some don't like to think there is anything to it beyond MHD, so they call anything involving plasma "MHD".
Are there other phenomena they see but don't like to talk about? Maybe?
Re: The James Webb Space Telescope is finding too many early galaxies
#369Earlier quoted context omitted.
I also vaguely recall something from The Simpsons… Edit: ha, found it: https://m.youtube.com/watch?v=ycvlJ9XMd94
Which itself is based off the intro the film Contact: https://youtu.be/EWwhQB3TKXA
Which is inspired by the Powers of Ten 1977 short: https://youtu.be/0fKBhvDjuy0
Re: The James Webb Space Telescope is finding too many early galaxies
#370Earlier quoted context omitted.
I don't think I've ever, out of all my physics classes up to grad seminars, been given the impression we have everything figured out. In fact, it was hammered into us that all we have are "effective" theories, at least when it comes to high energy physics, and that's not even talking about grand unification (electroweak + strong force unification), let alone Theory of Everything (electroweak + strong + gravity).
Maybe not where you studied, or at the level you studied, but in upper division undergrad physics at a top tier California school I definitely was given the impression that I should just crunch the numbers and not think too much about how it might be working.
Was this a quantum mechanics class? Thinking about how it might be working leads to strange things like the Many-Worlds Theory[1] and other very weird ideas. "Shut up and calculate" is the usual method of dealing with these deeper questions.
Beware; deep rabbit hole. [1]https://plato.stanford.edu/entries/qm-manyworlds/#:~:text=Th....