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James Webb Telescope Confirms That the Universe Is Expanding at Different Speeds

86 points| the__prestige | 1 year ago |tomorrowsworldtoday.com

97 comments

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digging|1 year ago

This is a poorly written article, it almost appears whole paragraphs are missing. For instance the phrase "an impossibly high value when compared to Planck’s measurements" is not explained at all. (Planck was a physicist, but I suspect they're referring to https://en.wikipedia.org/wiki/Planck_(spacecraft)

I think what it's actually saying is that we've confirmed that the Hubble tension is real. Whether or not that means different parts of the universe are accelerating at different speeds is still not clear. If the meaning of the results is deeper than that, it seems to have completely eluded the author who nonetheless wrote a breathless exaggeration of the findings.

EDIT: In 2024 actually I have to wonder if any humans were involved in the making of this article. It certainly doesn't appear to have passed an editor's eyes.

nabla9|1 year ago

This result has 8.3-sigma confidence, so it's as good as it can get statistically. Even greater confidence than that of the Hubble tension itself.

The Hubble Tension is real. The expansion of universe is accelerating.

mr_mitm|1 year ago

> The expansion of universe is accelerating.

We knew that before. This goes deeper than that. It accelerates in a way that cannot be explained by a constant dark energy density, which is part of our standard model. We have plenty of alternative models that can explain this, but our measurements are not precise enough yet to rule any of them out. Hopefully Euclid will provide data that is.

bashinator|1 year ago

Garbage article, clickbait tile; they're talking about the Hubble tension, not any kind of anisotropy in the Hubble constant. The latter would be actual news.

cl42|1 year ago

Can someone more familiar with the science help me out?

- On the one hand, the universe can be expanding at different rates.

- On the other hand, is it possible our approach to measuring the expansion (e.g., using Cepheid variable stars) might be the problem?

spenczar5|1 year ago

We don’t really know - you are right to ask this question. There are two methods and they disagree with each other. JWST is precise enough to rule out a simple reason like instrument imprecision.

So remaining possibilities are new physics, a deep flaw in our assumptions/methods, or a universe which is not uniform (but in a peculiar way).

magicalhippo|1 year ago

Becky Smethurst, an astrophysicist, goes through how the cosmic distance ladder works and the recent JWST results here[1].

As you say, measurement errors of Cepheid stars has been something scientists considered a possibility, hence why they're cross-checking by measuring them in different ways.

And, as mentioned in the posted article and the other papers mentioned in the video, it seems that measurement errors are very unlikely to be the culprit.

Preprints to the articles Becky mentions are here[2][3][4].

[1]: https://www.youtube.com/watch?v=3NeKR7bqolY&t=1330s

[2]: https://arxiv.org/abs/2401.04773

[3]: https://arxiv.org/abs/2401.04776

[4]: https://arxiv.org/abs/2401.04777

wuliwong|1 year ago

I've found this interesting and have read up a little on it. I believe there have been a good amount of studies trying to verify the different measurement methods. I believe they have made some progress in verifying the methods but I'm sure there is still more work to do. I think this is mainly in attempts to deal with the "cosmological crisis."

nabla9|1 year ago

Unless there is a "cosmic conspiracy" where Cepheid stars work differently when the distance from earth increase, that's not likely.

another_poster|1 year ago

Interesting, could a physical system exploit differences in the rate of expansion?

What happens to an object as it moves from a high rate-of-expansion region to a low rate-of-expansion region?

cwmma|1 year ago

the current thought is that these are measurement errors not actual differences in expansion rate but even if they were actual different expansion rates, they are separated by time not space.

starfancier|1 year ago

The "cosmic ladder" supposition's underpinnings are a bit shaky anyway. Calculating distance and age by examining ever distant Cepheid variable stars is prone to cumulative error. But it's the best estimate we've got.

kjkjadksj|1 year ago

If the universe expands at different speeds, is it even possible to determine expansion relative to earth since you don’t have something fixed (since everything is at different speeds) to measure earths local expansion against?

malfist|1 year ago

Yes, in fact, because the big bang happened everywhere and not in one central place, pretty much every part of space is moving away from Earth, so movement from earth is a pretty good measurement.

Think of it not as things moving apart, but that space, emptiness, is expanding. Like if you laid the universe out on a sheet of rubber and then pulled at the corners. Everything gets further apart and the expansion is happening everywhere

dataflow|1 year ago

Confused, are they saying that different parts of the universe are expanding at different rates? Or are they saying two methods give different results for the same parts?

1053r|1 year ago

The second one.

This result confirms that the "hubble tension" is real. In other words, two methods for measuring the expansion of the universe disagree, but we can't figure out why and have new and really strong evidence that the "cosmic ladder" method is correct. (The other method is based on the cosmic microwave background radiation and our best theories of physics, so we're caught between a rock and a hard place here: strong experimental evidence one way, and throwing out a ton of what we think we know about the universe with no obvious replacement the other way.)

SAI_Peregrinus|1 year ago

Two different methods give different results for the same parts. Very poorly phrased article.

usernamed7|1 year ago

given everything we already know about the fabric of spacetime, this makes sense. Every time we expect there to be an even distribution, we find more structure. So if something like dark energy is the driver of the expansion, and there is an unequal distribution of that, then this would be an expected outcome. But of course, without this new data it would be difficult to believe!

escapecharacter|1 year ago

this is because when we looking closely at the game bounds, God gets nervous and throws in some Perlin noise to keep us guessing

wutwutwat|1 year ago

But what is it expanding into? If the universe is expanding like a balloon then there's some sort of "edge". What is that edge expanding into? Imagine we had a craft that could take us to the edge and you could stand on it, the way you place your finger on the outside of a balloon. If you could stand on the outside/edge of the expanding universe, what would you see, that we're expanding into?

It can't be nothing. Something can't expand into nothing.

layer8|1 year ago

It doesn’t expand into anything. It has no edge. It expands within itself, like it’s distorting itself. Alternatively, you can picture it as groups of gravitationally bound objects (= galaxy clusters) moving away from each other everywhere in the universe. It’s a bit like raisins in a cake being carried away from each other by the dough expanding in the oven. Where the cake already fills all space infinitely in all directions, from the very start. Space is the cake dough. There is no “outer” space that space expands into. The geometry of space itself expands.

Still alternatively, imagine an infinitely extended graph paper whose grid size slowly and continuously increases, carrying with it the dots already drawn on it. Since the grid has infinite size from the start, it doesn’t expand into anything. It just expands.

throwway120385|1 year ago

Thinking of this kind of "expansion" using an analogy like a balloon does a disservice. When you get to large enough or small enough distances then our intuition often falls down completely.

In this case it's entirely possible for the topology of space to change such that it takes longer to travel from one point to another over time. If you consider a trip from point A to point B in topology A, and then topology A expands during the trip from point A to point B such that new distance is created, then the "distance" you have to travel to get to B is changing because at each moment along the trip you're at a different point.

If you think about it this way, the universe can be both expanding because it takes progressively longer to get from point A to point B, and it can also not be expanding into some "outer" area because there's nothing other than the universe.

It may make more sense to stop thinking in terms of distance and start thinking in terms of time. In that case, when you think of "expansion" what you're really describing is that at a constant speed, the closer you get to B, the more time it takes you to advance toward B. And if you change direction mid-trip to go to C, the "expansion" means that the amount of time required to reach C also increases as time elapses.

It's hard to say what's causing that expansion, but we can measure it by its effects on light traveling the same distance.

16bytes|1 year ago

The balloon analogy is a 2 dimensional example. If you are on the surface of the balloon, there is no "edge". You can go forever in any direction. If the balloon is inflated, it doesn't expand into something (remember we're in a 2D space, it's not a 3D balloon), it "expands into itself".

If you drew two dots on the surface of that balloon, those dots would get further apart as it inflated. What did those dots expand into? Well, nothing right? They just got further apart from each other on the balloon.

So, if you translate this into 3D space, that's what's going on. It's hard to visualize. It's not that the universe is expanding into something, it's that the space between every "point" in the universe is getting further apart.

https://bigthink.com/starts-with-a-bang/what-universe-expand...

qqtt|1 year ago

Like a lot of language we use when discussing things at the universe scale, the word “expanding” operates as a placeholder with analogs in day to day life but isn’t a perfect representation of what we mean.

The “universe” itself is space and time. When we say “expanding” we simple mean that galaxies are observed to be moving farther away from each other. That does not at all imply some kind of “expansion into another space” - space itself is exhibiting this property and we are observing it. That’s all.

The “balloon” analogy and the usage of the word “expand” in this context are both imperfect metaphors for physical phenomena we are observing.

It is a bit like trying to discuss what happened “before” the Big Bang - there is no “before” - time was created.

There are many phrases you can construct which may seem like they “make sense” but are actually combining a set of word concepts in ways that are self-contradictory.

“What is space expanding into?”

“What happened before time was created?”

Etc.

Night_Thastus|1 year ago

I don't agree. You're assuming that the universe is a distinct 'something' expanding into a distinct 'nothing'. I disagree, I think that the 'universe' is an arbitrary border we created.

If we were somehow able to accelerate a particle out past the edge of the known universe, now the bubble includes that particle too and essentially we've 'expanded' the universe. In other words, the arbitrary bubble containing things that we know about and consider significant is larger than it was before - because there's something out there we can observe.

windsurfer|1 year ago

The edge of the Mandelbrot set expands out to infinity and yet the area within the edge is finite. Who is to say that the universe isn't a hologram on a higher-dimensional Mandelbrot set-like object?

m3kw9|1 year ago

So it means it isn’t expanding like a sphere but like an irregular explosion?

1053r|1 year ago

No. This confirms that the "hubble tension" is real. In other words, two methods for measuring the expansion of the universe disagree, but we can't figure out why and have new and really strong evidence that the "cosmic ladder" method is correct. (The other method is based on the cosmic microwave background radiation and our best theories of physics, so we're caught between a rock and a hard place here: strong experimental evidence one way, and throwing out a ton of what we think we know about the universe with no obvious replacement the other way.)

foobarian|1 year ago

I get that the universe can be expanding, and that there might be different methods to calculate/measure this that have discrepancies. But that the rate of expansion is accelerating, how in the world is that possible?

epgui|1 year ago

What makes you think that should not be possible?

It's a pretty well accepted fact.

datavirtue|1 year ago

You should ask how fast the expansion is.

m3kw9|1 year ago

I thought universe is infinitely large, how is it expanding

Aachen|1 year ago

It's not that there is a shifting boundary where the universe ends, but what is meant with universe expansion is (per my understanding) that objects grow further apart over time without experiencing acceleration or any force acting upon them. It's like drawing a map on grid paper and then increasing the grid size without adjusting the scale: all distances become larger

This stretching includes any photons traveling across the grid, and the stretching causes them to expand. Longer wavelengths are more red, giving us the word redshift for stretched light rays. That's one of the ways we measure the expansion: see how much redder the light is as you look at more and more distant objects

notaustinpowers|1 year ago

From my understanding, The infinitely large theory relies on the Universe being incredibly complex in terms of dimensions. The best way to describe it is like a balloon Take a deflated balloon and draw two dots next to each other on it. Then blow up the balloon. The dots are further away from each other (universe expansion). And if you "walk" across the balloon, you can make a full circumference so you never run into an edge (infinite).

epgui|1 year ago

I'm not sure if we know that the universe is infinitely large.

I do know[1] that:

- it's larger than we will ever be able to know or observe (ie.: the observable universe is smaller than "all of the universe"... although that feels a bit hand-wavy to say)

- it's expanding.

---

[1] I am a scientist, but not a physicist. Everything I said could be wrong.

nabla9|1 year ago

Infinite can expand.

pmayrgundter|1 year ago

The [Study] has a better framing in its title "JWST Observations Reject Unrecognized Crowding of Cepheid Photometry as an Explanation for the Hubble Tension at 8σ Confidence".

It rejects the hypothesis that there was a systematic observational problem in observing Cepheid variables (CVs), which are in turn used to estimate distances to Type Ia Supernova (SNs), towards a long-term goal the Study concludes with of "Tying all of these together by observing large samples in common can lead to the calibration of ∼100 [SNs] and a <1% local measurement of [The Hubble Constant, H0], a landmark in our quest to understand the expansion of the Universe."

Notably the paper doesn't provide a new estimate of H0, but it does strengthen the case for CV/SN being at odds with other methods of estimating H0, a problem called the Hubble Tension.

JWST was built primarily to extend the sensitivity range for infrared observations, so we can see fainter sources from further away, or near sources with greater resolution. This study is about the latter.. the study of CVs and SNs in nearby galaxies.

"the significantly greater resolution of JWST over [Hubble Space Telescope] has greatly reduced—in practical terms, almost eliminated—the main source of noise in [Near-Infrared] photometry of [CVs] observed in the hosts of nearby [SNs]. The resolution of JWST provides the ability to cleanly separate these vital standard candles from surrounding photometric "chaff."

CVs and SNs are "standard candles", rungs on the Cosmic Distance Ladder[CDL], the framework we use to compare and contrast different astronomical distance measurements. The term "standard candle" is used for a physical process we think we understand well enough to use its appearance at astronomical distance to infer other properties of its observation, e.g. the candle's color shift towards red the further away it appears to be. ("appears" since we can't directly measure actual distances, but observe that galaxies get smaller/fainter/redder together)

Cepheids are a relatively common kind of star that pulsates regularly during its lifetime, while SuperNovas are much rarer one-time very bright events. SNs are really useful to see them far away bc how bright they are, but since there's so few of them, we calibrate nearby SN distances based on the many CVs in the host galaxy of the SN.

In all, this study starts by looking at CVs in NGC 4258 at 23 Million lightyears away, and then looks for photometric crowding of CVs at successively further steps away in NGC 5643 (41 Mly), NGC 1559 (48 Mly), NGC (1448 56 Mly) and NGC 5468 (140 Mly), but don't find evidence of crowding to account for apparent brightness/closeness of the CVs, so rejects that idea with a high confidence. Those galaxies are actually as far away as they appear to be if CVs are good standard candles.

These are at the nearer end of the CDL.. 140 Mly vs the observable Universe is thought to be at least 13 billion light years radius. But if it in turn makes us more confident about SNs, those go out to a current max of 16Bly[FarthestSN].

[Study] https://iopscience.iop.org/article/10.3847/2041-8213/ad1ddd

[CDL] https://en.wikipedia.org/wiki/Cosmic_distance_ladder

[HT] https://xkcd.com/2516/

[FarthestSN] https://en.wikipedia.org/wiki/SN_UDS10Wil

gagaJo|1 year ago

Cosmology feels a lot like quackery these days.

Does it even bother to rely on physics? Physical experiments show explosions do not propel all matter at the same rate.

James Webb telescope recently found galaxies that were “too old”, would have formed right after the Big Bang. The prevailing wisdom was all matter spread out evenly due to the Big Bang, then coalesced into galaxies (I emailed various researchers to confirm I understood this was indeed the consensus).

But again, other physics shows that clusters of matter ejected from explosions are never uniformly distributed.

Just more evidence the well educated (I assume if it’s concensus driven even the best educated agree) are just typical people and their expertise should be challenged constantly rather than sit back and assume things are figured out.

As Asimov illustrated in the Foundation, if you aren’t measuring for yourself you’re serving someone else’s interpretation.

Hyper-normalized social society just leads to normalization of outputs, which helps preserve and propagate poor science.

michaelmrose|1 year ago

Aggressive dismissal of an entire field with minimal attempt made to understand it is never going to play well and following it up with sarcasm doesn't improve the situation.

Attempting to work backwards to the beginning of the universe from a single tiny point in time and space is fairly obviously going to be a lot harder than understanding the physics of events we can repeat, measure, and examine. This doesn't make them quackery and it does explain why many things remain poorly explained. A century from now its likely that many understandings will be retained and some will have been consigned to the bin.

People do challenge existing theories. Most frequently unsuccessfully. Because most novel hypothesis turn out to be wrong.

Riffing off the science fiction reference this isn't a process we can skip any more than authors can skip brainstorming, first drafts, rewrites and just skip to typing out the final draft.

In brief stop coming off like Agent Mulder. Everyone knows the truth is out there. If it takes a while to coalesce its not because the educated folks working on the problem too stupid to listen to basic physics. It's because the physics that explains the rest of the picture isn't written yet.

addaon|1 year ago

> explosions… explosions

What are you drawing an analogy to explosions with in this comment? The Big Bang? Why do you expect the analogy to be as precise as you seem to take it to be?

Workaccount2|1 year ago

The fact that you seem to be interested enough to email experts about ancient galaxies, yet still are referencing the big bang as an explosion, leaves me utterly confused about your level of knowledge, but leaning heavily towards "no idea what they are talking about".

The big bang was not an explosion.

mr_mitm|1 year ago

> Just more evidence the well educated (I assume if it’s concensus driven even the best educated agree) are just typical people and their expertise should be challenged constantly rather than sit back and assume things are figured out.

As someone who worked as a cosmologist, I have trouble putting into words how wrong, out of touch and arrogant this statement is.

1053r|1 year ago

We have some pretty good ideas about just how "lumpy" the explosion of the big bang should have been. And yes, the best theories in cosmology disagree with the recent observations highlighted in this article. On the other hand, those cosmological theories are rooted in extremely strong physics which does things like predict various attributes of particles that have been measured extremely precisely and were predicted correctly. So the Hubble tension is real. My money is on the theory needing revising, but how? There are no great candidates for something to replace the standard model and our best theories in cosmology. There are plenty of candidates, but no obvious methods to choose a best one. This is science! Remember, the most exciting words in science are, "huh, that's odd." The Hubble tension is extremely odd!

epgui|1 year ago

You're so lost I'm not sure where to start.

Not that you really deserve help, with that attitude...

WithinReason|1 year ago

The Big Bang has nothing to do with explosions

nabla9|1 year ago

What you explain is the confusion that comes from reading news articles about science ans succumbing to nihilism and conspiracy theories.

Temporary_31337|1 year ago

Just as the Three Body Problem releases on Netflix and science starts to break down? ;)

dracovolans|1 year ago

This does not seem strange to me, since time does not flow the same everywhere - and phenomena occur at different subjective speeds.

spenczar5|1 year ago

I don’t understand what “time does not flow the same everywhere” means. Can you elaborate?

cwmma|1 year ago

Things like time dilation are accounted for in the measurements.