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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

#481

Post by moloch-hai »

eru wrote: post #385
DiggyJohnson wrote: post #357

Earlier quoted context omitted.

> Citation needed How could you possible find a citation for that? It’s not even pretending to be a scientific or totally objective claim. Asking for a citation for this type of statement is no way to have a discussion. Do you not see why?

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.

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

#482

Post by schiffern »

whatshisface wrote: post #406
schiffern wrote: post #366

Earlier quoted context omitted.

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 i…

> 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. There are objects like globular clusters and dwarf galaxies that lie outside the galactic plane, but are not that far away. If our galaxy's gravity was confined to its p…

I was hoping someone would mention globular clusters! I couldn't find a way to integrate it naturally in my post.

I don't see any information about globular cluster movement in that image. Naturally the confinement wouldn't be 100%, and some amount of gravity would still "leak out,"[1] so the mere existence of globular clusters isn't proof one way or another.

Surveying globular clusters offers a good test. RG might (or might not) explain why globular clusters are mysteriously 1) preferentially orbiting perpendicular to the primary galaxy's rotation, perhaps due to stability, and 2) preferentially aligned with each-other in their own plane, perhaps due to mutual (lensed) gravitation. Both of these observations are otherwise unexplained (or require numerous free parameters) under dark matter.

We won't know until someone does a survey, and probably some simulation work. Sadly MOND soaks up most of the oxygen in the Modified Gravity field, leaving almost none for RG.

[1] see Figure 16 https://arxiv.org/pdf/1603.04943.pdf

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

#483

Post by HPsquared »

moloch-hai wrote: post #279
azalemeth wrote: post #228

Earlier 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 it called "hydrodynamics" because of an assumption of incompressibility (like regular hydrodynamics vs aerodynamics)?

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

#484

Post by Beldin »

ndsipa_pomu wrote: post #455
throwawaymaths wrote: post #400

Earlier quoted context omitted.

The explanatory power of dark matter is so weak though. With the right clumping of LCDM you could probably also explain various reports of poltergeists around the world. Then you could claim that reports of poltergeists are evidence of LCDM over MOND because it's another phenomenon that MOND can't explain.

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.

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

#485

Post by mnw21cam »

AstixAndBelix wrote: post #250
User23 wrote: post #155

Earlier quoted context omitted.

There's a joke that calling Computer Science Computer Science is like calling Astronomy Telescope Science, but part of what makes it funny is the ring of truth to it. Our instruments really do limit our observations. The advantage Computer Scientists have is that we can glimpse a world of Platonic Forms[1], where Functions, and Sets, and Information exist, or something close enough for government work, merely through…

Computer Science doesn’t get the pass, unfortunately. First of all because it’s a branch of maths, so in reality it doesn’t have any instruments to worry about. Secondly, applied CS relies on an incredibly simple instrument: binary logic gates. The computers we have today are just a mesh of stuff that flips on and off with no intermediate states. That’s pretty primitive as a means of expression and computation compar…

A lot of people think that computer science is just a branch of maths. But when I was doing my doctorate, I was a computer scientist, and my three supervisors were a mathematician, an engineer, and a meteorologist. The difference between us was much more than the stuff we knew - it was the way that we thought, and therefore approached a problem. Supervision meetings were interesting - it very much felt like four people speaking four different languages.

On a very broad level (and I'll get loads of people disagreeing with this, because both mathematics and computer science divide further into different specialities), mathematics is primarily about proving logical truths, whereas computer science is about managing complexity. That's a massive cognitive difference, even if many of the problems the two fields tackle are the same.

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

#486

Post by moloch-hai »

mr_mitm wrote: post #454
somenameforme wrote: post #372

Earlier quoted context omitted.

This is exactly what pushed me away from pursuing cosmology. One of the most important 'discoveries' in cosmology was that of cosmic inflation [1]. The issue is that if you model the big bang, what it creates is nothing like what we see. Regions of space that wouldn't have had time to have become causally connected (nothing could have gotten between them even traveling at the speed of light since the time of the big…

> It's an absolute retrofitting of numbers to make a model fit reality. That's just called science. What else do you propose? Give up because you didn't get it right the first time?

It is one thing to identify a mechanism and show how in operation it must produce the numbers seen. It is entirely different to invent a name for a presumed mechanism, with no hint of how it happened to come to the numbers seen.

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

#487

Post by mnw21cam »

positr0n wrote: post #340
Dopameaner wrote: post #324

Earlier quoted context omitted.

I always wondered if we could somehow get a James webb telescope revolving around all planets of our solar system in the next 1000 years. That should give us pretty awesome visuals.

What would be the benefit of the telescope orbiting other planets than earth?

There's definitely a benefit to placing a decent telescope outside the asteroid belt. From Earth, we get a lot of light reflected from the Sun from dust orbiting somewhere between Earth and 2 AU from the Sun, which pollutes our space images - it's called the Zodiacal Light [0]. A telescope outside this light pollution would be able to see faint objects much more clearly and easily than Webb.

[0] https://en.wikipedia.org/wiki/Zodiacal_light

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

#488

Post by eru »

moloch-hai wrote: post #479
eru wrote: post #444

Earlier quoted context omitted.

Yes, I know. That's why I wrote >> Up until last year nobody had thought to see whether anything eats viruses! Turns out some do. > Nah, lots of things eat viruses. It's nothing unusual at all. You eat viruses, I eat viruses. They are everywhere, after all. > The novel finding was a critter that lives / can live solely on viruses.

You wrote it, but it was what we all understood already, making writing it nothing but an exercise in snark.

Not sure.

Eg creatures that eat plastic are still news, even if plastic is not their sole diet.

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

#489

Post by zelphirkalt »

alisonatwork wrote: post #231
zelphirkalt wrote: post #205

Earlier quoted context omitted.

I know it is considered increasingly unlikely, but: What a parallel to flat Earth ideas people had (...) hundreds of years ago, until they realized we are on a sphere. Maybe in a few hundred years people will laugh about our limited ideas of the universe as well.

This is wrong by an order of magnitude. It was already known thousands of years ago that the Earth is more-or-less spherical. The idea that people in recent history believed in a flat Earth is a myth.[0] [0] https://en.wikipedia.org/wiki/Myth_of_the_flat_Earth

That does not really detract from my comment though. Thousands of years are also hundreds of years. Just more hundreds. So if we are getting technical about that, I don't think it is wrong what I wrote. Still, thanks for putting the time frame a bit clearer.

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

#490

Post by zelphirkalt »

midoridensha wrote: post #378
alisonatwork wrote: post #231

Earlier quoted context omitted.

This is wrong by an order of magnitude. It was already known thousands of years ago that the Earth is more-or-less spherical. The idea that people in recent history believed in a flat Earth is a myth.[0] [0] https://en.wikipedia.org/wiki/Myth_of_the_flat_Earth

>The idea that people in recent history believed in a flat Earth is a myth. The way you've worded this, you're incorrect. There are people today who believe in a flat Earth, crazily enough. Of course, the idea that most of society (namely educated people) believed in a flat Earth is a myth. From your link: "The myth of the flat Earth, or the flat earth error, is a modern historical misconception that European scholar…

If we had to guess (of course not good research to be guessing): The typical person working on a field probably believed what the church told them the world looks like. If they ever heard about being on a sphere, they would probably laugh and point to the horizon, saying: "How can Earth be a sphere? Don't you have eyes to see? Look into the distance, all is flat!" and any kind of argumentation, that it is simply so huge, that one cannot see it, would seem to them like a made up story, a lie to further some hidden agenda the explaining person has.
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