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.
The Hubble Tension is real. 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.
There was an amazing paper on this published on HN a year or three ago that explained at certain discrete points in the future, entire percentages of the known universe will be beyond our reach. It was profoundly beautiful and sad at the same time.
I'll try to dig it up.
Edit: found the post (three years ago) and some of the quotes and figures I pulled from it:
https://news.ycombinator.com/item?id=26734913
Edit 2: another commenter had made a note about the Big Rip. I was writing a response, but they unfortunately deleted their (good) comment. I'll include my response below:
> wait until you find out about the Big Rip (paraphrasing)
That one's even wilder. To think every atom of every place and loved one you ever touched would vanish infinitely far away. Every atom and then subatomic particle of your own once corporal body, regardless of its final resting place, torn and scattered.
Last Contact is a great short story if you're in the mood [1].
Then there's vacuum collapse and all the other theories.
I wonder what humans or human descendents 500 years from now will figure out about the universe's ultimate fate.
[1] https://zestfullyblog.blogspot.com/2011/02/last-contact-by-s...
[0] https://iopscience.iop.org/article/10.3847/2041-8213/ad1ddd
[1] https://en.wikipedia.org/wiki/Hubble%27s_law#Hubble_tension
expansion rate in the early universe << expansion expansion rate.
-> accelerated expansion .
- 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?
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).
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
What happens to an object as it moves from a high rate-of-expansion region to a low rate-of-expansion region?
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
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.)
It can't be nothing. Something can't expand into nothing.
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.
That's not an explanation, that's incoherent ramblings that make zero logical sense
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.
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...
I'm talking about 3d that we live in. We're currently standing on a ball of dirt, if the earth started to swell up, the surface we're standing on would expand into space. The thing we're standing on that's pushing outward is what I mean by "edge".
What is the universe expanding into? If it's pushing outward in all directions, it's pushing into something, the same way a swelling earth would expand into space
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.
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.
I don't think that the scientific definition of the universe matches this. It's a physical thing, not a construct we made up. It's not an imaginary line between two countries.
The universe is full of things which have mass. Those things are rapidly expanding outward. What are those masses expanding into as they "blow up the ballon" and push the boundaries of the universe outward? It can't be nothing, it's physically impossible.
EDIT: might as well quote people smarter than I
> The universe is all of space and time[a] and their contents.[10] It comprises all of existence, any fundamental interaction, physical process and physical constant, and therefore all forms of energy and matter, and the structures they form, from sub-atomic particles to entire galaxies. Space and time, according to the prevailing cosmological theory of the Big Bang, emerged together 13.787±0.020 billion years ago,[11] and the universe has been expanding ever since. Today the universe has expanded into an age and size that is physically only in parts observable as the observable universe, which is approximately 93 billion light-years in diameter at the present day, while the spatial size, if any, of the entire universe is unknown.
It's a pretty well accepted fact.
I also have the layman awareness of some kind of missing mass sometimes explained by "dark matter." But I did not see the additional explanation that this "dark matter" also acts as a repulsive force to accelerate the expansion. Maybe large scale structures manage to create propulsive forces that happen to point away from the center? Anyhow I would love to know what the mechanism is there.
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
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.
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
[FarthestSN] https://en.wikipedia.org/wiki/SN_UDS10Wil
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.
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.
They’re just as much avoiding real work of keeping themselves alive as an aristocrat to noodle around something that will only ever be incomplete due to our axiomatic systems being leaky abstraction.
I’m a “Perelmanite.” The ethical and communication standards of academia serve its social influence goals, not science.
We get the gist of natures mechanics and know how to measure generally. Further specialization of the syntax rarely moves the needle, which still points at Einstein, Gödel, and other century old works, rarely the contemporary librarians of scientific texts except to say “yeah this customization still preserves the whole of relativity” or some other core body of work we infer modern research form.
Perelman figured out Riemanns at home, alone. Bailed on university as he found it mired in politics and manipulation of social agency to preserve itself.
See that recent article about institutions becoming road blocks to the progress they were created to resolve. There’s been article after article here about science depts veering into pseudo-science. When a workers salary depends on them ignoring truth… “meat suit needs to eat” wins above honesty and integrity.
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?
Let’s not pretend the replication crisis isn’t real and endemic within academia these days.
The big bang was not an explosion.
Okay, then lets hear your interpretation of what it was.
This isn’t a forum for PhD defense.
So glad the takeaway is about a single word. While the idea that researchers are failing left and right which reaches into everyone else’s lives is left untouched. Likely because you’re the sort that relies on people buying the con about your efforts.
Reality is not a neatly organized set of decoupled microservices. It’s a monolith and bad science radiates through our lives.
Experts should not have the influence over society they demand.
As someone who worked as a cosmologist, I have trouble putting into words how wrong, out of touch and arrogant this statement is.
A lot of my insight into academia (since it’s been almost 30 years since I graduated and left it behind me) is influenced by academics tired of and often disgusted by their peers dishonesty about their work. Theory after theory have more in common with religion; they were made up.
Historians in my social scene say there’s solid historical evidence advanced degrees were invented as a payola scheme between landed gentry and the church; money for BS theology degree the illiterate public could not falsify. Over specialization doesn’t really make net new discovery so much as normalize old ones, but we keep up the role-play of history and anoint geniuses and the like.
Give them resources and prestige to do some math. Grigori Perelman would like a word on what’s required resource wise to do math. Out of touch and arrogant westerners.
Similar trend going on these days where the innumerate serve BS they cannot begin to try to falsify. Just so happens much of it isn’t reproducible anyway, but the can’t argue that or the out of touch egos of a minority of the populace that make up academia would crumple in outrage.
Offense at minor slight is so endemic to human nature, so general an emotion it impacts all of us.
Out of touch and arrogant is applies just a neatly to academics being normal humans and all.
Not that you really deserve help, with that attitude...
I good followup could be something like "I read about relativity and I still don't understand the connection you're making to this current article or something like that - but it doesn't seem fair to skip a basic Google search before asking for elaboration.
