The James Webb Space Telescope is finding too many early galaxies

https://skyandtelescope.org/astronomy-news/the-james-webb-space-telescope-is-finding-too-many-early-galaxies/

by cainxinth • 4 years ago

764 514 4 years ago

mabbo• 4 years ago

Ethan Siegel isn't so certain: https://bigthink.com/starts-with-a-bang/most-distant-galaxie...

The tl;dr is that we're finding quite a few red galaxies and red can mean distant (and therefore old) but you need to follow-up and do further direct measurements of each galaxy to be really certain that it's old and not red looking for some other reason.

Some of these unexpectedly red galaxies have been followed up on, and some are indeed old, but it's not enough data points yet to be certain of anything.

The fun part of science is that either way it's pretty exciting!

namaria• 4 years ago

Yes! Beautiful pictures and scientists scratching their heads? This telescope is awesome!

rossdavidh2• 4 years ago

They do talk about that a bit in the article:

"These candidates await spectroscopic confirmation: Their redshifts are only estimates for now. But so far, spectroscopic confirmations of other galaxies have confirmed the vast majority of preliminary distances. Even if only half of Yan’s selection turn out to be nearby galaxies masquerading as distant ones, the latter number would still be unexpectedly large."

cevn2• 4 years ago

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?

ajross• 4 years ago

The very early universe can't be observed with visible light. It was filled with ionized hydrogen and thus opaque over long distances. The oldest light is from the era of "recombination", when things had cooled enough (c. 370k years after the big bang by consensus models) to permit light to travel. This is just the thermal glow of the universe, redshifted (way, way) down into the radio spectrum. And we can see it just fine; it's the cosmic background radiation and has been very well studied.

It's the region between recombination and the currently-visible-to-telescopes galaxies that Webb is particularly well-suited to study.

rjrodger• 4 years ago

Visible light was scattering off densely packed electrons up to about 300k years after the Big Bang - so I guess - white.

ben_w3• 4 years ago

White, redshifted so hard it's the blackest black we ever experience.

(I want to add a H2G2 joke here, but I can't figure the right way to reference making God disappear in a puff of logic related to the Babelfish…)

shadedtriangle• 4 years ago

We can see it and it’s called the Cosmic Microwave Background https://en.m.wikipedia.org/wiki/Cosmic_microwave_background. It’s not t=0.0000001 though as the time before the cosmic microwave background the universe was opaque to photons, you wouldn’t be able to see anything.

klodolph• 4 years ago

Correct me if I'm wrong.

Cosmic microwave background is behind the galaxies, and we can see it. The universe is mostly transparent these days, so light can travel across the universe from a distant galaxy to our eyes or telescopes. Long ago, the universe was full of ions-free electrons and protons-and these are very effective at scattering light, so the universe was effectively opaque at that point. The universe became more transparent as the universe shifted towards hydrogen atoms instead of free electrons and protons.

Whatever the universe happened to look like during that transition period, from opaque to transparent, is still what we see. It's the cosmic microwave background. Anything from before that time got absorbed.

jfengel4• 4 years ago

Yep. That is all correct.

It's conceivable that we could observe gravitational waves during that period before the CMB, because they're not blocked by the un-recombined electrons and protons. If we ever get there, it could help explain the small variations in CMB from place to place. But that's a long way off.

feoren• 4 years ago

Not an expert here but it sounds like you might be describing the Cosmic Microwave Background. This is basically the remnant of the early opaque plasma cloud that filled the entire universe. As we look far away/back in time, the photons reaching us have redshifted due to the expansion of the universe. That's why these originally extremely high-energy photons are now just low-energy microwaves. The "background", 0 seconds after the Big Bang, is in all directions, and presents as the Cosmic Microwave Background. Or so I understand.

https://en.wikipedia.org/wiki/Cosmic_microwave_background

Pxtl• 4 years ago

There's always a relevant xkcd for every science question, and in this case it's one of the first ones:

https://xkcd.com/54/

soiler3• 4 years ago

We can actually already see that time period, in its present form. It's called the Cosmic Microwave Background. It is the (now extremely cold) energy which permeated the entire universe in that very early time period. The entire universe was opaque and extremely hot... then as it expanded, it began to cool enough for particles and then atoms to form. Only then were stars possible, and later galaxies.

How/why can we see the CMB? Well, it was everywhere. Literally every point in the universe was a nearly uniform sea of blazing energy. So if you look far enough in any direction, you will see the cold echoes of that time period.

edit: Beat to the punch! I hope among our many answers you've found something enlightening

edit 2: Important to note that the CMB is not synonymous with the beginning of spacetime. It is more like a wall, beyond which we can't see anything, and it came down very early in time.

drexlspivey• 4 years ago

Kinda relevant xkcd that was published today https://xkcd.com/2723/

bpye2• 4 years ago

and it came down very early in time.

Is this just because we’ve used it to define the start?

Tuna-Fish• 4 years ago

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 electrons in high temperatures, they don't form in the ground state. Instead, the newly minted hydrogen atoms are in a highly exited state. As they fall back to their ground states, they emit infrared photons at ~3000K color temperature. These photons, redshifted by the expansion of the universe to ~2.7K, are the Cosmic Microwave Background, the uniform ultimate backdrop we have when looking in any direction.

[0]: Which has it's slightly incorrect name (should not have re-) because it was named before the big bang became a widely accepted or known theory.

seanw4443• 4 years ago

So if we can see CMB in all directions, why do we really even say "the observable universe" as though there could be more matter and more galaxies beyond what we can see? If the maximum of what we can see is implied to be before all galaxies, then shouldn't it be implied that all galaxies that exist can be seen?

lp4vn• 4 years ago

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?

pseudobry• 4 years ago

the uniform ultimate backdrop we have when looking in any direction

Is the CMB exactly uniform in every direction? Or is this early light slightly more redshifted when we look up versus when we look down or left or right? Does the oldest light we see in any given direction vary slightly in color?

I'm imagining the universe expanding as a sphere from a central point, but we're located off-center. Wouldn't the early infrared photons emitted from the other side of the central point of expansion from us be observed by us now as a slightly different color than the early infrared photons emitted closer to the edge of the early expanding universe?

A rabbit hole of questions: - When did space start expanding? - Did it have to rapidly expand for 400k years as extreme forces propelled matter apart? - Was that expansion faster or slower than the current expansion of space between galaxy groups? - Is expansion uniform across the universe? - Or is expansion slower closest to the original center of the universe? - Maybe there's a central point in the universe that's not moving relative to a reference frame outside our universe? - Is space discrete or continuous? - As space expands do new "units" of space appear between units of space that have grown farther apart? - If not, wouldn't physics work differently for areas of space where the units of space have grown farther apart than areas of space where the units of space aren't as far apart?

cevn2• 4 years ago

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..

mandevil• 4 years ago

As everyone has already pointed out, the Cosmic Microwave Background Radiation is as close as you can get to the Big Bang.

But to the larger point, these galaxies were suspected before, based on Hubble work. You see, the COBE satellite from 1989 to 1993 mapped the microwave background radiation very precisely (two of the Principal Investigators on COBE won the 2006 Nobel Prize in Physics for this work). And they found that while there are minute fluctuations in the radiation, those fluctuations are measured at the parts-per-million level of difference. But the Hubble has found that the farthest back galaxies it could see were some of the largest and most massive things ever witnessed. So we had this gap between 'everything everywhere is the same to parts per million' and 'there are some supermassive galaxies' and so the Webb telescope was specifically designed to find the things that were redshifted so far they were out of the visible spectrum (so Hubble couldn't see them) but not so far that COBE could see them in microwave: in the infrared spectrum that lies between those two, that's where Webb is supposed to focus and help us understand how these galaxies form.

Because this question of what happened between the CMBR and the visible light range is the biggest question left over from Hubble, so it is what drove the design of the Webb. This is how astronomy has worked for centuries: you build a new telescope to answer some questions, but that leaves you with more questions, so you need to build new telescopes to answer those questions, GOTO 1. That's what's been happening ever since Galileo looked through that telescope at Jupiter all the way back in 1610.

b800h2• 4 years ago

There is a wonderful sequence in the (2nd?) Book of Enoch (~150AD?), where the viewer is transported up through the heavens, past the planets, and finally beyond the stars, and eventually sees the incomprehensible face of God lying behind it all, visible all across the far end of space.

So perhaps that? :-)

moloch-hai14• 4 years ago

Great flaming letters spelling out "We apologize for the inconvenience".

throwawaymaths9• 4 years ago

Worth noting: For a very long time MOND has been predicting earlier galaxies than LCDM.

JetSetWilly• 4 years ago

This is not unusual. There's many predictions made by MOND ahead of the fact that are borne out by reality. But don't worry - dark matter will be "retrofitted" so that it fits the facts and everybody will suffer collective memory loss again.

Edit: see for example table 1 on page 12 here: https://arxiv.org/pdf/2110.06936.pdf from a review of prior expectations by both MOND and dark matter vs how they turned out against reality for a large variety of astrophysical scenarios.

varjag2• 4 years ago

But MOND itself is a "retrofit" to make it agree with the data, isn't it? It's in the name.

thereddaikon• 4 years ago

Dark matter is the umbrella term for the observed discrepancies. MOND is one possible possible explanation for DM. The paper you linked doesn't compare MOND to DM, because that doesn't make any sense. It compares MOND to ΛCDM which is a competing explanation.

sebzim45007• 4 years ago

Am I understanding that paper correctly that their suggested solution to explain the Bullet Cluster using MOND is too introduce an additional kind of matter which can not be detected on earth and doesn't interact with light (namely sterile neutrinos)?

Is this satire?

puffoflogic• 4 years ago

Yeah, but is it even worth saying that when the response will inevitably be "so what?" by the entrenched anti-MOND orthodoxy?

rqtwteye2• 4 years ago

As far as I know , MOND is not compatible with some observations. So dark matter and MOND have to be tweaked to agree with what we see.

6nf2• 4 years ago

MOND is not compatible with all observations but neither is dark matter. A lot of scientists think MOND is a better explanation than a new particle that we've not yet observed. Have a look at Sabine Hossenfelder's work for some of those arguments.

cwkoss• 4 years ago

Is it possible that the 'edge' of universe reflects light? Have scientists been able to conclusively rule that out somehow?

Does the universe even have an edge? What is our current understanding of what the boundaries of the universe might be like?

eganist• 4 years ago

Is it possible that the 'edge' of universe reflects light? Have scientists been able to conclusively rule that out somehow?

It's not an edge the way you think. It's the edge of what we can see based on the known age of the universe and how much light has reached us. I.e no real boundaries as best as we can tell.

The best way you can look at this is that early galaxies are being found earlier than expected based on our model of how the universe formed. The further you look, functionally the further back in time you look (not just further away)

This is an oversimplification and an astrophysics expert can give you something better.

pwatsonwailes2• 4 years ago

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.

8note• 4 years ago

I wouldn't be surprised if there's a hawking radiation equivalent for that edge, but the wavelength is on the order of the size of the universe, so basically impossible to measure

afro882• 4 years ago

I guess it's reasonable to assume that there are parts of the universe that are far older and much further away (ie, their light hasn't reached us yet). Which would mean we can never really guess the age of the universe. We can only guess the age of our local area?

Which kind of sounds a bit like the whole "everything revoles around earth" transitioning to "everything revolves around the sun". The universe is what light has reached us transitioning to the area of light that has reached us is just a small spec of the actual universe?

soulofmischief2• 4 years ago

We have a concept of the Particle Horizon, the max distance light could have traveled in the universe, and that is our boundary, our effective edge of the universe.

There's the concept of the light cone, which is the total volume of observable light which can ever reach an observer, or inversely, the total volume ever traveled by a given point source. The expansion of the universe means that there is a certain boundary, a horizon where the universe expands too much for light to ever travel the required distance.

https://en.m.wikipedia.org/wiki/Particle_horizon

https://en.wikipedia.org/wiki/Light_cone

jacobr1• 4 years ago

An analogy might be the horizon. There is no fixed horizon, it is just the boundary of how far your can view, given both the curvature of the earth and the quality of your eyes. It is relative to where you are on the earth, and by your altitude. So while it is calculable, it isn't a fixed boundary like a river, or a wall.

colordrops• 4 years ago

How does this work with the big bang happening at a specific point in the past?

soiler3• 4 years ago

What is the edge of the universe? How would you define that? In most models, the universe doesn't have anything that could be called an edge. Unless you are referring to the boundary of the local universe, which is defined as the sphere around us at which objects are too far away for their light to ever reach us. It's not a physical structure that could reflect light, it's more like the opposite of that.

teraflop• 4 years ago

No, we have no evidence that the universe has any kind of "edge" that is topologically different from its interior.

There is a boundary to what we can see. As the early universe cooled, it changed from an opaque plasma to transparent gas. So as we look farther away, and also backward in time, we see the last point at which it was opaque; this is the cosmic microwave background. But this isn't a "real" boundary that something could hit. And it long predates the formation of galaxies, so it couldn't have reflected images of galaxies.

chrisweekly3• 4 years ago

also (citation needed, this is from memory from university cosmology classes over 20y ago, maybe misremembering or info out of date) the shape of the universe may be less like a sphere and more like a toroid, or a multidimensional moebius strip.

so (hand-wavy, impossible IRL but maybe illustrative / fun to think about) if you could freeze time and look far enough in one direction, you'd see the back of your own head.

ben_w3• 4 years ago

The far limit of the visible universe is the cosmic microwave background, which is the heavily red-shifted view of when all of space was filled with an opaque plasma of similar temperature to the surface of a star[0].

The galaxies we're seeing are in front of that.

[0] 3000 K, https://en.wikipedia.org/wiki/Recombination_(cosmology)

lostmsu• 4 years ago

This is hard to internalize. Why do we continue seeing CMB? My understanding is that the early galaxies still produced light after recombination.

twawaaay2• 4 years ago

The edge of visible universe is Big Bang. Or more concretely, the time couple hundred thousand years after Big Bang when the universe became translucent to light.

Things cannot "reflect off of the edge of visible universe" because that would require that the light travel back in time which is nonsense.

As of this moment we cannot exclude possibility of discontinuities in the universe which would be cause for example by inflation. But we also have not observed any.

0xbadcafebee• 4 years ago

if time is a dimension, and we can only see the past and the present, could it not be that, if one's gaze were shifted, one could see the future? effectively looking at the "other side" of the dimension of time? looking straight at one "side" of time, you can only see the past and present. but if you had a galactic set of mirrors set up around "time", couldn't you "see" the other side where the future lies? effectively you'd be looking at a reflection of the future.

or, time being malleable (relative to things like mass and movement), wouldn't it be possible to refract or bend time the way light is, such that you could see things (that already happened in the past) sooner, even if they are really far away? maybe like how bending a race track can allow a vehicle to exert more force or go faster, but with light?

xcskier56• 4 years ago

I have a memory from when I was a kid and learning about the universe. In my head it definitely had an edge, and it resembled a really really big hockey rink with boards. But it was also only 2d at that time, which I think I remember knowing that wasn't right but not being able to conceptualize a 3d universe. So yes, in the universe of my 8yo mind the "edge" might reflect light

jhoechtl2• 4 years ago

My theory: It's not an edge but we look onto ourselves back in time. As space and time evolves, it's hard to identify as such.

One day we will recognize that we essentially were looking onto space to see ourselves while starring. The last thing is meant metaphorical.

CuriouslyC• 4 years ago

Talking about the edge of the universe implies space is a thing. Physics works just fine if you imagine the x, y and z of particles describes an arbitrary set of coupled attributes on the particle itself. It is more likely that space is an emergent property of the entanglement between information, and in that case the idea of a boundary is nonsensical. Under that model, "spacetime" would behave like a foam - if one bit of it pulled far enough away from the rest it'd shoot off as a bubble.

badrabbit• 4 years ago

Space and time are intertwined interstingly that way. If time somehow loops back or reverses (circular time) the it is not unreasonable to suggest space also loops back. Is it possible that at a certain boundary of space and point in time you loop back and start over at 0:0:0/0:0:0 space/time coordinates. At least in this current realm of reality, is it like one big space-time movie on a loop?

cwoolfe• 4 years ago

Obligatory xkcd: https://xkcd.com/2622/

rubymancer• 4 years ago

That comic just made my mind bend.

ash2• 4 years ago

This discovery of the early galaxies seems to make “huge-looking iPhones far away” xkcd obsolete.

starik36• 4 years ago

Does this mean that big bang either didn't happen or happened in a different way that we think of it? Or happened far earlier than we think it did? Complete layman here.

rossdavidh2• 4 years ago

I think it's safe to say that it is still uncertain, but few (not zero) astronomers believe that it means the Big Bang didn't happen.

downrightmike• 4 years ago

We have lots of theories, but we'll never be certain as we will never see back to the BB. Everything was hot plasma for 370k years after the BB. We can get maybe that close, but no further. We are still exploding anyways.

pndy• 4 years ago

I'm not an expert but from what I understand, scientists observed the very distant galaxies which shouldn't be visible according to most popular model of the universe evolution. And if these observations will be confirmed then we might get more accurate model which totally differs of the most popular one the scientists agrees upon.

Far distant young galaxies should be seen as "red", but these aren't and that's the issue here - JWST captured these very bright. It's possible that the universe evolves in a different way and Hubble's law doesn't applies

https://en.wikipedia.org/wiki/Hubble%27s_law

russdill2• 4 years ago

Incomplete/unconfirmed data is showing some discrepancies for what our tentative models of the early universe predict. The data could be wrong or misinterpreted, the models could be wrong, incomplete or misinterpreted, or the could be fundamental problems with the very foundations of cosmology. The models we have of early galaxy formation are very incomplete and based on very little data. It's exciting to get data that will discover new things about the early universe and help refine those models.

jayzalowitz• 4 years ago

I may be stupid, but considering that the models of galaxy stability are based on a universe where we are made from star stuff and not energy stuff, is it not possible that they formed way quicker with less complication because it was basically only hydrogen and empty space?

jchanimal• 4 years ago

Thanks that blew my mind, had to go tell the folks in the next room. Cool perspective. Where can I learn more?

college_physics2• 4 years ago

I don't know if this instance qualifies as one, but I think its fair to say that cosmology is the one domain of "fundamental" physics where "discrepancies" or question marks keep piling up and not really resolving.

It the pattern of previous science revolutions repeats, there could come a point where reinterpreting the large existing body of knowledge using a different paradigm would explain an number of "oddities" in a more economical way.

I don't know if this generation of telescopes will get us there but it feels that this is a plausible outcome over the next 1-2 decades. Which would be very exciting :-)

barbazoo• 4 years ago

It the pattern of previous science revolutions repeats, there could come a point where reinterpreting the large existing body of knowledge using a different paradigm would explain an number of "oddities" in a more economical way.

Could we train a GPT3 like model with the entire corpus of astronomical research and try to answer some questions that way?

Enginerrrd• 4 years ago

I'd say not a chance.

GPT3 can regurgitate, and, in my opinion, even use knowledge, but I don't think it can synthesize knowledge.

largbae• 4 years ago

Already done. They came back with the answer: "42"

purpleblue• 4 years ago

If you give GPT3 code with a bug in it, and ask it to find the bug, it can't really do that. I'm pretty sure giving it all the data and asking it why things aren't working the way it should, it wouldn't have actual knowledge.

There's a depth to explaining things that GPT still can't do. It's still astonishing, and has completely changed my idea on what AI can do, like write plays with very incredible context (better than most humans!) but there are still major limits.

soulofmischief2• 4 years ago

The article mentions that they're training neural networks to classify these objects. Give it a decade and this kind of high level number crunching will be as common as calculators are today. Transformers will find their place in all of this, and I am confident we will have a breakthrough in a few years regarding novel synthesis.

anon291• 4 years ago

FWIW, I've tried asking ChatGPT to walk through some thought experiments.

Things like, what happens if I shoot two bullet at c/2 in opposite directions on a train going at c/2? Now suppose, I'm an outside observer. And then trying to introduce quantum gravity.

My thought was that perhaps it could 'reason through'. Unfortunately, it was unable to. Eventually, it said that this is an unsolved problem. In other words, it 'recognized' the thought experiments. Perhaps if you use a phrasing that's not in the literature.

EDIT: Actually, just checked again, and chatgpt can't reason through relativity anymore:

Me: Imagine I'm on a train traveling at half the speed of light. I'm in the middle of a car and I fire bullets going at half the speed of light towards the front and back of the car. Do the bullets arrive at the front and back of the car at the same time?

ChatGPT: No, the bullet fired towards the front of the car will arrive at the front of the car first, while the bullet fired towards the back of the car will arrive at the back of the car later. This is because the front bullet is moving in the same direction as the train and the back bullet is moving in the opposite direction of the train. The relative velocity of the bullet and train will determine the time it takes for the bullet to reach the front or back of the car.

college_physics2• 4 years ago

well, you could. And it might not be a complete waste of time. I would not expect any directly useful answers(...). But producing a semi-random collation of sentences that spans the corpus of cosmological facts and models and asking scientists to review / draw "inspiration" from it might remove some of the biases of the average cosmologist (like having to follow the latest publish-or-perish fad). This would only be useful if the answer is sort of hidding in plain sight (within the published stuff) and you tweak the algorithm not to ignore weird observations or theories that are not cited a lot.

But the beauty of science (and the human mind driving it) that important progress happens with creative jumps that invent completely new things (e.g., new mathematics) and frequently bear little resemblance to the past

_Algernon_• 4 years ago

GPT3 cant even play tic tac toe properly (at least in my attempts). What makes you believe it can build and manipulate a model of the universe, and then answer questions about that model in a way that goes beyond what humans can do?

Cthulhu_8• 4 years ago

I think chatbots can probably answer known things, but we'll still need smart humans for original ideas.

That said, I can imagine a chatbot can help as a rubber duck, bring up things that weren't considered yet, or be so wrong as to kickstart the human into a breakthrough.

sebzim45007• 4 years ago

I think this says less about cosmology and more about the incredibly effectiveness of the standard model in the regime we can test directly on earth.

If we compare ΛCDM to most other scientific theories it doesn't look so bad in terms of discrepancies. Certainly there are many unexplained effects in solid state physics, there isn't even an accepted explanation for why rubbing a balloon on your head makes it stick to a wall and that's an experiment you probably did as a child.

Eduard2• 4 years ago

there isn't even an accepted explanation for why rubbing a balloon on your head makes it stick to a wall

But the accepted explanation is "static electricity", no?

Or do you mean we don't "really" know when asking a couple of follow-up "why?" questions further?

foxyv5• 4 years ago

there isn't even an accepted explanation for why rubbing a balloon on your head makes it stick to a wall

You mean dielectric moments and static electricity? Electromagnetism is the one thing we know the most about. It's that spooky gravity junk that makes us scratch our heads. It never seems to behave quite right and doesn't mesh with all the other forces.

tim-fan• 4 years ago

Relevant xkcd: https://m.xkcd.com/2682/

And from the alt-text:

"Friction-driven static electrification is familiar and fundamental in daily life, industry, and technology, but its basics have long been unknown and have continually perplexed scientists from ancient Greece to the high-tech era. [...] To date, no single theory can satisfactorily explain this mysterious but fundamental phenomenon." --Eui-Cheol Shin et. al. (2022)

AnIdiotOnTheNet• 4 years ago

Also there's that whole "worst prediction in the history of physics" thing with the Vacuum Catastrophe.

vl2• 4 years ago

Certainly there are many unexplained effects in solid state physics

Wait for it… Why ice is slippery?

Usual explanation is completely incorrect. Actual semi-conclusive research just recently happened.

azalemeth2• 4 years ago

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...

comicjk• 4 years ago

My understanding is that the standard model likely does predict static electricity, but since it's a phenomenon bigger than a few molecules, we have no way to actually run the simulation. The physics is willing but the computers are weak.

TillE2• 4 years ago

My favorite poorly understood phenomenon in basic physics is the Mpemba effect, where hot water can freeze faster than cold water under certain circumstances. It's just phase changes of water in a simple experiment you can do at home, and I think there's still no widely accepted explanation.

WalterBright• 4 years ago

there are many unexplained effects in solid state physics

Looks like there is plenty of opportunity for newly minted physicists to make their names and careers!

simonebrunozzi• 4 years ago

ΛCDM

Lambda-CDM Model [0], for the ones like me who haven't heard it before.

[0] https://en.wikipedia.org/wiki/Lambda-CDM_model

gmadsen• 4 years ago

which part. how is that not electostatics and van der walls forces?

WithinReason• 4 years ago

The relevant XKCDs:

https://xkcd.com/1867/

https://xkcd.com/2682/

jackmott42• 4 years ago

I don't think it is fair to characterize cosmology as not making progress no. Stuff is far away and occluded and hard to measure and see. Each improvement in observation causes a need to refine previous ideas, as expected. There are of course the two big mysteries that have lingered for a long time: Dark Matter and Dark Energy, but other areas of physics have lingering mysteries as well.

teawrecks• 4 years ago

I almost had the same reaction, but technically they didn't say anything about cosmology not making progress. It's entirely reasonable to assume a scientifically minded person describing a field as "piling up question marks" means they think it's making a LOT of progress. Imagine a field that answers questions more often than it finds new ones; that'd be a pretty stagnant field to be in.

moloch-hai14• 4 years ago

Nobody says cosmology is not making progress.

People dunk on cosmology because cosmologists have consistently, over decades, insisted, in public, that they knew more than they did, and are continually obliged to abandon what they insisted they knew. If they were more forthright about how much they don't know, they would get less criticism. They have much to learn from the biologists, who know they know practically nothing (even though massively more than you), and are happy to say so.

The health of a branch of science may be read from how eager its researchers are for you to know about what they have no clue about.

gibolt• 4 years ago

The number of possibilities are countably infinite. Makes sense that we will keep finding things we don't understand for a long time.

freedude2• 4 years ago

Fields of science should always be willing to change based upon empirical evidence.

I think there are several other scientific areas where we know less than we ought.

1. The sub-atomic level

2. The cellular level

3. Ocean biology

4. Geology, particularly effects of earthquakes and volcanic activity

5. Weather patterns over time

NovaVeles2• 4 years ago

I feel for the Weather pattern folk. All of the one I have spoken to over the years are pretty cool. They are trying to model an insanely complex system - oh but thanks to global warming they are struggling to make models that work for longer than a few years because it all keeps changing!

yreg6• 4 years ago

What are the indicators we have marine biology wrong to the level of the other mentions?

mmusson• 4 years ago

It may be more a question of a new generation of physicists, willing to consider that particle dark matter is not the explanation for the acceleration discrepancy.

dylan6044• 4 years ago

Sadly, I'm to the point that unless we call it the Kardashian Space Telescope, the draw to new generations will not be there. We're closer to Idiocracy future than Interstellar future.

pantsforbirds• 4 years ago

Would you bet that we'll see a paradigm shift of a similar nature to the classical physics -> quantum mechanics / relativity paradigm change, but for Cosmology in our lifetimes?

jacquesm• 4 years ago

The answer to that will highly depend on how old you and the GP are.

gitfan863• 4 years ago

Yes, we are in the middle of a huge shift in the definition of intelligence. AND that could have enormous impact on our perception and ability to see reality.

User23• 4 years ago

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 the intellect. Astronomers have no such luxury.

[1] Or whatever circumlocution you prefer to express the same general concept.

AstixAndBelix• 4 years ago

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 compared with the rest of the universe

raxxorraxor• 4 years ago

Astronomers probably should go on the quest for immortality since otherwise you are basically condemned to look at a still image. Even if that image contains a story from the earliest universe until now. It is a million states, but no real process.

What I find so fascinating is that the observations are still quite precise. How do you know the outer rims are rotating too fast? Couldn't this be some gravitational lensing and stars are actually much closer to the core than they appear?

How do you even begin to estimate the mass of a galaxy? How do you weight the behavior of a disc and combine it with keplers law to even see that something is wrong here? As a layman I would be perfectly happy with how galaxy are rotating... I find it fascinating that much is so precisely determined that we have to miss something.

suetoniusp91• 4 years ago

The simulation gets less cohesive the farther from earth you look.

peatmoss2• 4 years ago

I was just thinking about video games where vegetation, animals, and hills spring into existence when you get close enough. Far away, and they don't bother to render the little things.

Depending what generation tech we're running on in the parent reality, JWST may be causing a noticeable jump in system load.

ordu• 4 years ago

It is a v0.93 of simulation, which was run a long time ago. Software was patched since and now simulation is much smoother.

77pt77• 4 years ago

Everyone knows that general relativity is broken.

Plus cosmology has the problem that you can't really conduct reproducible experiments.

Dopameaner• 4 years ago

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.

eru10• 4 years ago

Huh, why would you want to do that?

If you have the resources to spare, you can do much better than replicating James Webb style telescopes. See eg https://en.wikipedia.org/wiki/Solar_gravitational_lens

positr0n• 4 years ago

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

Cthulhu_8• 4 years ago

I want to venture that 1000 years is pessimistic. I just hope governments or private entities open up their wallets to build and launch more and better telescopes.

I'm reading the whole JWST project is estimated to cost $10 billion. That's about 4.4 overpriced Twitters, 77 US Department of Defense budgets (just for 2023), and 11.7 Facebook annual revenues.

We have the technology and the means, what's lacking now is the will.

odieldomanie• 4 years ago

There is the esoteric "Cosmological Natural Selection" theory that predicts the discrepancies. This guy at https://theeggandtherock.substack.com/archive explains his version of this theory (albeit in an emotional way) that I find a pleasant read.

EZ-Cheeze• 4 years ago

It's an amazing theory that I now share.

F R A C T A L H A T C H E R Y

fartsucker693• 4 years ago

not surprising imo, because of how limited our observational capabilities are. we'd probably progress quicker if we could look at far away stuff up close instead of from billions of light years away.

jononomo• 4 years ago

I've always wondered where the universe is.

djfobbz• 4 years ago

Thanks to Adobe, the universe and all of its galaxies have now been found!

jscipione• 4 years ago

RIP Big Bang Theory

timmg• 4 years ago

I have no idea if it is the end of the Big Bang Theory, but I think it would be super fun if it is:

* It doesn't have a negative effect on anything if it turns out to be wrong (other than some theses).

* It would be pretty cool to get a sense for how fallible we are

So I'm rooting against Big Bang Theory just for the experience of it :)

sebzim45007• 4 years ago

Depends what you mean by the big bang theory. The theory that the universe expanded almost from a point will probably survive forever, but ΛCDM might not survive the decade.

DesiLurker• 4 years ago

Cue Laugh Track

bcaulfield• 4 years ago

Great news. Finding stuff that doesn't fit into the current model and we need smart people to get to work understanding may be the surest sign that the JWST is invaluable.

Waterluvian• 4 years ago

This reminds me of how when you’re right, you don’t learn much. When you get it wrong, you learn a ton.

gitfan863• 4 years ago

We have known that the current model of physics is wrong for a long time. But the main focus has been on math. "If only we could figure out this formula, then we would understand everything"

It seems much more likely that we are not missing a formula but a basic understanding of reality. Much like the early astronomers trying to find a formula for the movement of the sun and planets that put Earth at the center of the universe

pleb_nz• 4 years ago

You learn more from mistakes and being wrong no doubt about it.

I remember some billionaire saying 15% of the decisions you make each day should be mistakes otherwise your not trying and you're not learning.

xp84• 4 years ago

Same - I really like seeing things like this.

Not only because it means we're about to learn some big stuff, but also because it would be completely *preposterous* if humans at our puny stage of development had already correctly figured out every last detail about insanely complex things like the exact size, age, and origin and age of galaxy-sized things that developed tens of billions of years ago, billions of light-years away from the tiny rock we stand on. Getting things wrong shows that people are actually doing science honestly!

Teever• 4 years ago

What stage of development do you feel is necessary to acheive what you're describing?

How can a human at this puny stage know this?

atemerev• 4 years ago

Something is wrong with the cosmic distance ladder. Space is anisotropic, or gravity interacts with itself somehow. The distances are not what they seem to be. I think this will eventually be the solution to the galaxy rotation / dark matter problem.

zmgsabst• 4 years ago

Our who claim that things are isotopic seems in conflict with what we see:

https://www.quantamagazine.org/asymmetry-detected-in-the-dis...

https://www.newscientist.com/article/2280743-enormous-strand...

Personally, I think this is strong evidence that primordial anyons were inflated — and we’ve failed to account for the energy these stored from inflation.

https://en.wikipedia.org/wiki/Anyon

1970-01-012• 4 years ago

I've often wondered if matter from another galaxy is behaving the same way it does here on the macroscopic level, but varies at the atomic level.

jfengel4• 4 years ago

It's pretty clear that it's the same at the atomic level as well.

The spectra look exactly like they look here. They're red-shifted, but the gaps between the peaks are exactly the same. That comes from the atomic level, the way the electrons are arranged within the atom.

If something were different at the atomic level, it would surely change the characteristics of the light they give off. The only way to see what we see would be if there were two things different, that somehow counteracted each other in the things we can see but were nonetheless different in some other factor we can't observe.

That's not impossible, but it would be a bizarre coincidence.

1970-01-012• 4 years ago

Doesn't spectra come from the Rydberg constant, which is set by several other universal constants?

https://en.wikipedia.org/wiki/Rydberg_constant#Alternative_e...

xwdv• 4 years ago

Ok, so if the Big Bang Theory is bunk, what’s the next leading alternative creation theory?

sebzim45007• 4 years ago

Something which sounds exactly like the Big Bang Theory to a layman but whose expansion satisfies a different equation.

robg2• 4 years ago

Instead of one big bang, imagine an infinite number of big bangs, all colliding on a cosmic scale in time and space. That’s not necessarily a multiverse, but it is a megaverse with universe as the old paradigm.

freedude2• 4 years ago

ok, but what caused the big bangs?

...

Genesis 1:1

bruce343434• 4 years ago

ok, but what caused Genesis 1:1?

...

big bang

SketchySeaBeast• 4 years ago

You've just moved the "what caused the..." question up another level and then pleaded that your new level is somehow more special than the previous level without any actual justification. It's turtles all the way down and gods all the way up.

russdill2• 4 years ago

https://en.wikipedia.org/wiki/Eternal_inflation

robg2• 4 years ago

Yes, just why assume a multiverse and not a megaverse? Of course, the superhero movies (which I enjoy) give an unrealistic view of what a multiverse would be.

luxuryballs• 4 years ago

I always wonder if light traveled billions of years to get here wouldn’t it be possible that it got distorted along the way? What if all these galaxies are just a sort of a typical pattern of what light looks like after an unfathomably long journey through space/gravity/time/etc? It could be likely that what we’re seeing is no indication of what was ever actually out there.

jesse_faden• 4 years ago

It does. One effect of light passing through gravitational wells is gravitational lensing.

https://en.m.wikipedia.org/wiki/Gravitational_lens

There is also Redshift.

https://en.m.wikipedia.org/wiki/Gravitational_redshift

not2b• 4 years ago

This is good. If we merely confirm what we expect to see, then we don't learn anything new.

echelon• 4 years ago

Not so sure. If we're not early ourselves, the likelihood that the universe is swimming in intelligence -- if not already part of an enormous computational fabric -- is higher. That naively seems like it would place an upper limit on Earth-originated intelligences.

Jweb_Guru• 4 years ago

Would that be such a bad thing?

TheOtherHobbes• 4 years ago

I'm going to be very amused if the Steady State Model - an unpopular relic from the 1940s - turns out to be correct.

https://en.wikipedia.org/wiki/Steady-state_model

airstrike• 4 years ago

Speaking of unpopular pet theories from the 1940s, I'm a fan of the https://en.wikipedia.org/wiki/One-electron_universe

EDIT: There's also this super fun PBS Space Time episode on the theory: https://www.youtube.com/watch?v=9dqtW9MslFk

Cthulhu_8• 4 years ago

I love this theory because it's both mindblowing and yet, when you think about it, weirdly makes sense. Assuming time travel etc, of course.

marricks• 4 years ago

There’s also more spiral galaxies than expected!

If steady state gained favor that would be super fun, but this quote from the article seems to throw a little cold water on that.

At the same time, she notes that yesterday’s disks are different than modern ones. “They’re not today's Milky Way,” she notes. “They're turbulent, they're messy, and we need to study them more.”

dark-star2• 4 years ago

My favorite theory is that the universe is finite, some sort of (hyper)sphere or -torus. If we could just look far enough out there we would see our own galaxy

What would be even cooler is if it was warped like a moebius strip in a higher dimension, so that when we look out there, everything is mirrored from "our" reality :-D

delecti2• 4 years ago

That first theory would be interesting, but wouldn't it be basically impossible to prove unless the finite repeating universe were also pretty small? We see distant objects as they were in the past, and I'm not sure we'd recognize our own galaxy a billion years ago and a billion light years away.

It's actually an interesting thought experiment. If that theory were true, and assuming we could see ourselves face-on (rather than edge-on), then I wonder how far away and far back could we recognize ourselves.

satvikpendem• 4 years ago

You should read the short story The Tower of Babylon by Ted Chiang who also wrote Stories of Your Life, the inspiration for the movie Arrival.

deepsun4• 4 years ago

That assumes that we can somehow see through time, which leads to a whole bunch of inconsistencies (aka time travel paradoxes). There's no way to look through large distances without looking back in time, unfortunately.

Cthulhu_8• 4 years ago

For all we know it might be - or it might actually be infinite - but the trouble is that we're limited by what we can see / detect, which is in turn limited by the speed of light.

Another commenter asked something like, what if the universe is much bigger than the observable universe, because everything beyond that 'border' has redshifted out of reach - or hasn't reached us yet / never will, because it's moving away faster than the speed of light.

brap2• 4 years ago

Since everyone is mentioning their favorite whacky theories, mine is the one that says within every particle is a whole universe, made up of particles with their own universes and so on, and what we call our universe is really just a particle in an even bigger universe. And what if all of those universes were actually the same universe, like some infinite recursion?

Is there a name for this?

someotherperson• 4 years ago

Men in Black marble hypothesis?

https://www.youtube.com/watch?v=OKnpPCQyUec

thinkmcfly• 4 years ago

I dunno, I felt like this was a huge cop out in the movie Men in Black

ckw• 4 years ago

Animal House: https://youtu.be/JUOGxePBs50

Pascal:

  […] But to show him another prodigy equally astonishing, let him examine the most delicate things he knows. Let a mite be given him, with its minute body and parts incomparably more minute, limbs with their joints, veins in the limbs, blood in the veins, humours in the blood, drops in the humours, vapours in the drops. Dividing these last things again, let him exhaust his powers of conception, and let the last object at which he can arrive be now that of our discourse. Perhaps he will think that here is the smallest point in nature. I will let him see therein a new abyss. I will paint for him not only the visible universe, but all that he can conceive of nature's immensity in the womb of this abridged atom. Let him see therein an infinity of universes, each of which has its firmament, its planets, its earth, in the same proportion as in the visible world; in each earth animals, and in the last mites, in which he will find again all that the first had, finding still in these others the same thing without end and without cessation. Let him lose himself in wonders as amazing in their littleness as the others in their vastness. For who will not be astounded at the fact that our body, which a little while ago was imperceptible in the universe, itself imperceptible in the bosom of the whole, is now a colossus, a world, or rather a whole, in respect of the nothingness which we cannot reach? He who regards himself in this light will be afraid of himself, and observing himself sustained in the body given him by nature between those two abysses of the Infinite and Nothing, will tremble at the sight of these marvels; and I think that, as his curiosity changes into admiration, he will be more disposed to contemplate them in silence than to examine them with presumption.

  For in fact what is man in nature? A Nothing in comparison with the Infinite, an All in comparison with the Nothing, a mean between nothing and everything. Since he is infinitely removed from comprehending the extremes, the end of things and their beginning are hopelessly hidden from him in an impenetrable secret, he is equally incapable of seeing the Nothing from which he was made, and the Infinite in which he is swallowed up.

narag4• 4 years ago

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 really know.

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 now it seems they're not so sure.

cryptonector3• 4 years ago

If there is another reason the light from distant galaxies turn to red, kind of a long-distance light fatigue, we couldn't really know.

It's not just red shift that demands an explanation, but also that the sky (space) is dark. If space wasn't expanding then the skies would be bright white.

Another thing is the second law of thermodynamics, which very strongly implies a lot of standard cosmology.

Of course, standard cosmology could be all wrong, but these deductions are quite solid as far as the physics that we know today.

mr_mitm8• 4 years ago

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.

jmyeet• 4 years ago

Cosmology is one of those fields where I suspect we'll always be finding things that don't match with theory because we can never know nor replicate the initial state of the Universe.

There's also a lot of fundamental questions we don't have answers on. For example:

- What does space expanding actually mean? Is space stretching or is new space being created? If so, what is the mechanism for that?

- Is time a fumdanental property of the Universe or is it an emergent property?

- What are the fundamental intereptations of quantum mechanics [1]?

And so on.

The cosmic microwave background is our earliest yet observation from the Universe. Before this the Universe was really too dense and hot for radiation signatures to survive. Interestingly, we may be able to peak even earlier than that with the cosmic neutrino background [2].

But there are a ton of things about the early Universe's formation and expansion we will probably never know and will only be able to guess at with models that will always break at a certain point.

[1] https://www.southampton.ac.uk/~doug/quantum_physics/interpre...

[2] https://en.wikipedia.org/wiki/Cosmic_neutrino_background

albertgt• 4 years ago

df = pd.DataFrame( universe )

Warning: Specify dtype option on import or set low_memory=False.

UltraViolence2• 4 years ago

So there could've been civilizations that are literally BILLIONS of years ahead of us? Imagine what these people know about the universe!

This reminds me of the Star Wars lead-in: "A long long time ago in a galaxy far far away." It really could've happened you know!

foxyv5• 4 years ago

What's even crazier is that those civilizations could have built and advanced for a 100 million years and we would never know about it because they are so far away. The light from Canis Major, our closest galactic neighbor, is older than our civilization (25,000 years). The average distance between galaxies is 1 million light years. For all we know, there have been billions of civilizations that have lasted longer than the lifetime of our solar system and we haven't even seen the light from them yet.

The universe is huge!

yreg6• 4 years ago

Earth came quite late to the party and it spawned life relatively soon after.

That's why it's strange we haven't discovered any Dyson spheres/swarms (in any galaxy).

Either life is indeed absurdly rare, or Dysons are impractical for some reason, or there is a way to mask heat.

tuatoru• 4 years ago

Earth life uses lots of different elements - at least two generations of supernovas required. Not really that late if you allow for that.

scotty794• 4 years ago

I don't know. Life needed almost 5bn years to get to this point on Earth. Let's say we lucked out and it almost always takes 3 times as long. Then we look like early birds in the Universe.

What's more, earlier solar systems had a bit boring chemistry. We need a lot of supernova made stuff to really function so this narrows the time window.

You might think that near galactic core there's a lot of really cool stuff made but I think interstellar environment might be less stable because of that and maybe life doesn't even have a 5bn years of quiet time to develop there.

UltraViolence2• 4 years ago

You don't know that. Life might be possible with simpler chemistry too.

Chemistry was sufficient 100 million years ago for intelligent life to evolve, so some other solar system could've easily have had intelligent life for that long or even longer if they were lucky.

Our lives have changed beyond recognition in the last 500 years. Imagine a civilization that's thousands, tens of thousands or even hundreds of thousands of years ahead of us.

mixmastamyk• 4 years ago

The first ones are beyond the rim now.

naikrovek• 4 years ago

I don't know why articles are titled like this. it's annoying, though, I'll tell you that

we are finding the exact correct number of galaxies of the exact correct ages; our expectations are wrong, or how we determine what we've found is wrong. generally, our understanding is wrong. not the rest of the entire universe.

hapticmonkey• 4 years ago

Experiment results that disagree with theory is EXCITING. I hope this contributes to progress and I'm giddy just imagining the model of the universe we have 50 or 100 or 500 years from now.

Spkeat• 4 years ago

This can further reinforce the idea that the unobservable universe was always there and that the big bang is only a pattern of movement of the cluster of galaxies and it is only the information that has managed to arrive from our position.I want to see how big bang theory falls into an optical illusion.

WXLCKNO• 4 years ago

I don't know which idea is harder for me to conceptualize.

That something has always existed or that it came to exist out of nowhere-ish.

SV_BubbleTime• 4 years ago

I suspect this is why simulation theory is popular.

mansoon• 4 years ago

Once you factor time out of your pre-universal reality, these are compatible.

scotty794• 4 years ago

Can you do spectroscopy on images of the galaxies to see how much stuff other than heydrogen and helium there was?

10g1k• 4 years ago

A lot of academic/scientific belief is based on ignorance. Hear me out.

The entire academic/medical establishment believed the appendix was "just a vestigial organ" which served no purpose. It was taught in every university, in every textbook. Every medical professional knew it was a fact. Why? Because they had not identified a purpose. In their ignorance, they adopted the position "I don't know what it does, therefore I can state as a fact that it does nothing." Except it turned out they were all wrong, for a very long time.

The appendix is not the only example of that mentality.

The same has occurred when it comes to estimates of the age of the universe.

When the most powerful telescope could see N lightyears, people believed the universe was N years old. Tiny gains or new images using that telescope adjusted the estimate to N.fraction years.

When the most powerful telescope could see 2N lightyears, people believed the universe was 2N years old. Tiny gains or new images using that telescope adjusted the estimate to 2N.fraction years.

When the most powerful telescope could see 3N lightyears, people believed the universe was 3N years old. Tiny gains or new images using that telescope adjusted the estimate to 3N.fraction years.

This happens every time. Yet astronomers and cosmologists refuse to learn the lesson, and keep repeating the same mistake.

deadbeeves4• 4 years ago

Vestigiality is not about having no function, but about losing the original function. Vestigial organs are also often in an atrophied state when compared to analogs in other species. The appendix is indeed vestigial, and while not entirely without function, it is almost entirely without one, to the point that you can not have it and not even realize it.

When the most powerful telescope could see N lightyears, people believed the universe was N years old. [...]

What are you talking about? Before the 20th century it was believed that the universe was eternal. After then, advances in determining the age came primarily from theoretical models, not improvements in equipment.

Yet astronomers and cosmologists refuse to learn the lesson, and keep repeating the same mistake.

You seem to be under the misapprehension that the goal of science is to not make incorrect statements. It's not. It's to incrementally (by necessity) learn about reality. There's nothing with the statement "by our best current measurements, the universe is about 13 billions years old" even if tomorrow new findings point to it being twice as old. To demand otherwise would mean that no conclusions can ever be drawn, because necessarily all scientific conclusions are tentative. It is true at all times that tomorrow's evidence may overturn today's conclusions.

eointierney• 4 years ago

Our scientists are engineers and our artists are logicians.

The telescopes are always amazing

idlewords• 4 years ago

This 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 model.

Whether or not you find the evidence persuasive, McGaugh's blog is worth a deep dive just to appreciate the subtleties and complexities of this kind of observational astronomy.

schiffern2• 4 years ago

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

[2] https://en.wikipedia.org/wiki/SOFAR_channel

whatshisface2• 4 years ago

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 plane, you would expect nearby external objects to move differently from how they are observed to move. See illustration:

https://cdn.britannica.com/23/4423-050-964A0A08/Distribution...

jquery2• 4 years ago

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 epicycles of Copernicus.

nickelpro• 4 years ago

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 missing mass, if we figure out the nature of DM or discover this hitherto unknown "standard matter" then we can talk about modifying universal gravitation.

[1] https://web.archive.org/web/20160721044735/http://www.astro....

cdogl• 4 years ago

I am too ignorant to weigh in on MOND vs dark matter, but this seems entirely possible.

In all domains - not only physics - there are many possible models that seem to match our observations. They’re continually adapted over time in order to meet to perceived needs and reality (see: the medieval European church).

Paradigm shifts can happen incremental or explosively. With the enormous sunk cost in our existing models - not least the millions of people educated in them - incremental change becomes harder. If MOND or any alternative theory is “true”, it faces a distinct challenge: there are decades of experiments and observations that have been fit to our existing model. To take over, it needs to answer _all_ of it - or provide so much utility that the incentives shift.

Success can be paralysing. In tech, a new idea can come along and shake everything up by showing results and solving a problem. The only way a new model of physics can do that is by generating a practical breakthrough. I hope I’m wrong!

fartsucker693• 4 years ago

MOND mispredicts many, many past discoveries. This would have people scrambling for alternative explanations immediately. Dark matter is simply a better fit for what we see.

Second, I don't know why MOND seems simpler and more elegant to you than literally something that doesn't modify the laws of physics at all but just increases the mass you use in computations.

moffkalast4• 4 years ago

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. 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. Adjusting equations doesn't really work in this case, there must be something physically there.

I'm not sure why this isn't mentioned first thing every time in dark matter discussions because it's literally the only thing that's pretty hard evidence imo.

ngcc_hk2• 4 years ago

Epicycles is what Copernicus fought against. Have he also have some I am not aware of ?!

Epicircle come about if one consider earth is the Center and some planets sometimes move backwards and then start to move forward again. You do not have that issues with Copernicus.

But he made a mistake of using circle. The observation guy using everything rotate around the sun and sun around the earth … a wrong model but the key is not the model but the observation he made. His record keeper Kepler finally found some other patterns and Newton get the … the rest is history.

I do not go to wiki or internet to check out the phrase. But epicircle …not of Copernicus.

ilitirit• 4 years ago

I've been out of the loop for a while. Can MOND satisfactorily explain gravitational lensing?

hackernewds• 4 years ago

It doesn't entirely, but Refracted Gravity does.

astroH2• 4 years ago

So MOND does predict more galaxies at high redshift however it also predicts earlier reionization than LCDM which it turns out not to be true and the mass function of clusters is not what we see purely based on X-ray temperatures. So getting one thing right at the expense of many others doesn't make this particularly viable.

SaintSeiya• 4 years ago

Maybe, just maybe the Universe is infinite and eternal? and the big bang never happened?

nuker• 4 years ago

The Universe AI is trolling us.

8bitsrule• 4 years ago

Some more interesting food for thought:

The classical big bang cosmological models describe gravitation by Einstein’s general theory of relativity. These models are able to treat the matter content of the universe quantum mechanically where appropriate, but they do not take into account the interplay of quantum theory and gravity.... The earliest universe was presumably quantum mechanical through and through, and we can no longer describe its initial conditions in a classical language. We must instead treat the whole early universe as a quantum system and formulate its initial conditions in the language of quantum mechanics.... Quantum gravity theorists have not shied away from the challenge. At present there are some half a dozen contenders...."

https://www.einstein-online.info/en/spotlight/quantum_cosmo_...

xyzal• 4 years ago

Articles like these make me want to stop doing everything and isolate in the basement for several months to study physics. Then I realize I have a family to feed and elderly parents to take care for.

Sigh, so many beautiful mysteries in the world, and only one life.

edit: A friend told me germans have the word "Sehnsucht" to describe such a feeling. So I guess it might be somewhat universal.

yipbub• 4 years ago

Same, but I imagine doing it in a country house with a table looking out into a lovely garden, and a mountain path nearby for long walks thinking about things.

Cthulhu_8• 4 years ago

I'm sure there's a catchy phrase for that kind of thing, intellectual cottagecore maybe?

jstummbillig• 4 years ago

It was beautiful and unexpected that this was not a "but"-one-up or "but"-and-here-is-why-you-are-wrong.

ankit2194• 4 years ago

I have kind of done that for last few months. Chat GPT helped immensely with that. I recently even asked if it's worth it to go back to academia. Still exploring that.

A few things that I recently understood or read about.

- Fermi Paradox - with help of chatgpt https://imgur.com/a/LuVV6iK

- How the age of universe was calculated.

- Redshift

- How age of solar system was calculated. I previously thought just like the universe is expanding, so is solar system. Turns out that is not the case. The distances have been more or less fixed. (i thought sun would be losing some mass, weakening gravitation for that to happen, nothing like that).

- Exo-planets.

- a lot of nuclear physics.

- Parallel universe theory according to quantum mechanics.

- gravitational waves (how to measure ripples in spacetime https://www.wired.co.uk/article/catching-cosmic-rays-virgo-i...)

- Theories around nuclear fusion and how ML, High Temp super conductivity and more precise chips are making advances possible.

And so on.

Will add one special mention to this: https://www.quantamagazine.org/why-this-universe-new-calcula... (this universe exists because it has the highest entropy is a layman summary of the article)

go_elmo• 4 years ago

Chances are significant that some explanations received are just not true as chatgpt does that too, unfortunately.

kettleballroll• 4 years ago

Interesting approach. Aren't you worried that chatgpt is feeding you bullshit without you noticing? I'd imagine chatgpt read as much science fiction content as science one, so there's no way to know if it tells the truth or hallucinations. How do you deal with that?

smcnally• 4 years ago

Anton Petrov regularly covers topics like these and encourages sharing with people interested in space and sciences.

https://youtube.com/@whatdamath

lnkl• 4 years ago

Seems like https://www.edx.org/xseries/astrophysics?index=product&query... would be of interest to you.

wolfi1• 4 years ago

although there is a german word for everything, "Sehnsucht" just means "desire"

mr_mitm8• 4 years ago

I don't know if it's any consolation, but a few months are not nearly enough to understand this on a meaningful level. I spent almost a decade studying physics, still feel like I don't really understand it and could barely wait to get out at the end.

znpy• 4 years ago

I spent almost a decade studying physics, still feel like I don't really understand it

This is the part that’s actually consoling.

saboot• 4 years ago

For me, it's been learning about the topic of last year's nobel prize in physics. Shedding light on Einstein's famous "God does not play dice" through, literally college algebra and a somewhat mundane experimental setup. The only thing stopping people from doing it sooner was obscurity and a comfortable attitude towards to status quo!

Now I'm convinced we can understand really fundamental things about our reality, and that is so so interesting.

I'm dreaming of going back, getting a math master's, then a physics PhD ... Maybe

acqbu• 4 years ago

only one life? don't be so sure about it

beefield• 4 years ago

Sorry for an likely ignorant question, but can someone ELI5 why we are confident that evereything in universe is less than 13 billion years old or whatnot, and not just redshifted beyond recognition?

twojacobtwo• 4 years ago

As I understand it, the most basic calculation came from modeling the Cosmic Microwave Background temperature changes in reverse time. If I recall correctly, that runs into a discrepancy that requires the addition of inflation to account for it.

Synaesthesia• 4 years ago

One of the great things about JWST is it can observe galaxies that are so distant, they're red-shifted that theyre in the IR spectrum.

mr_mitm8• 4 years ago

Because you can literally see the remnants of the big bang. Basically, if you look out far enough, you see a wall of plasma from a time where the universe was so hot and dense that light couldn't travel freely. It's called the cosmic microwave background and is impossible to explain in a static state universe. Before you get to the wall, you first see younger and younger stars (which we can tell by their composition, which influences their spectra), then a region which is void of galaxies (because it is such a young region of the universe that galaxies hadn't yet formed), and then said wall.

Not only that, but the CMB's properties, like its frequency spectrum or its tiny anisotropies match what you would expect to an astonishing degree.

https://en.wikipedia.org/wiki/Cosmic_microwave_background

astroH2• 4 years ago

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 Universe.

"Yan found 87 distant galaxies behind the galaxy cluster SMACS 0723" --> this is not true. They found 87 galaxy candidates. To be fair to the article, they do note that these await spectroscopic confirmation but experts only believe those with spectroscopic confirmation. Everything else is tentative and we don't yet have good numbers on confirmation rates. Finally, the Yan et al candidates are wildly inconsistent with almost every other estimate of high-redshift galaxy samples. You can see a comparison in Table 4 here: https://arxiv.org/pdf/2212.06683.pdf. They claim more than double the number of high-redshift sources compared to everyone else. JWST data is still very new and hard to both reduce and analyze. One particular problem is correlated hot pixels which can appear as very high-redshift sources. I don't know if this impacts the Yan et al paper but just an example of something that is not 100% straightforward to deal with. I highly recommend people take this with a healthy amount of skepticism until everything has a spectrum.

gala8y• 4 years ago

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.

ngcc_hk2• 4 years ago

The need of counterpoints and different views are important especially in academic field. But some debates got us lost as well. I would not say bad against YT but more about lack of quality one. Hope that will come.

Take an example of MONO discussed below. One claimed it is right but wrong in other prediction.

“ So MOND does predict more galaxies at high redshift however it also predicts earlier reionization than LCDM which it turns out not to be true and the mass function of clusters is not what we see purely based on X-ray temperatures. So getting one thing right at the expense of many others doesn't make this particularly viable.”

But the major discussion shifted to dark energy and refracted … and totally ignored that wrong predictions by mono … it is just hard to follow the threads.

But more discussion may help.

The James Webb Space Telescope is finding too many early galaxies

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