this post was submitted on 15 Jul 2023
430 points (93.9% liked)

Technology

59656 readers
2658 users here now

This is a most excellent place for technology news and articles.


Our Rules


  1. Follow the lemmy.world rules.
  2. Only tech related content.
  3. Be excellent to each another!
  4. Mod approved content bots can post up to 10 articles per day.
  5. Threads asking for personal tech support may be deleted.
  6. Politics threads may be removed.
  7. No memes allowed as posts, OK to post as comments.
  8. Only approved bots from the list below, to ask if your bot can be added please contact us.
  9. Check for duplicates before posting, duplicates may be removed

Approved Bots


founded 1 year ago
MODERATORS
 

New research puts age of universe at 26.7 billion years, nearly twice as old as previously believed::Our universe could be twice as old as current estimates, according to a new study that challenges the dominant cosmological model and sheds new light on the so-called "impossible early galaxy problem."

top 46 comments
sorted by: hot top controversial new old
[–] ProcurementCat@feddit.de 100 points 1 year ago* (last edited 1 year ago) (3 children)

many scientists have been puzzled by the existence of stars like the Methuselah that appear to be older than the estimated age of our universe

No, not really, because the age of that star is compatible with the age of the universe within the error bars.

These galaxies, existing a mere 300 million years or so after the Big Bang, appear to have a level of maturity and mass typically associated with billions of years of cosmic evolution.

Galaxy formation is still an active area of research und different models predict different evolutionary rates

Instead, he proposes a constant that accounts for the evolution of the coupling constants.

That's exactly what Brans-Dicke theory is trying to do, and other modified theories of gravitation as well. Yet they can't explain stuff so well as Lambda CDM can.

Overall, tired light pretty much doesn't work well explaining the perfect black body behavior of the cosmic microwave background or surface brightnesses of galaxies.

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

[–] kescusay@lemmy.world 29 points 1 year ago (1 children)

Yeah, I'm not convinced, either. It seems like every couple of years, someone puts out an announcement that Lambda CDM is dead, other scientists take a look, and a much quieter announcement correcting their work gets put out.

[–] jalda@sopuli.xyz 23 points 1 year ago

Yes, this is a bit frustrating. Part of the scientific method is to propose new hypothesis, and that's what the original author did, so no issue with that. But then there is a chain of increasingly pop-sci media that hype some of these hypotheses as they were already confirmed and accepted by the mainstream scientific community, which is not the case. For example, the title of the article, "New research puts age of universe", that is pure clickbait, the correct tense is, being very generous, "could put".

And when this happens in a field like cosmology, it's relatively harmless. But the same happens in fields that have a more direct impact in the general public's life, like the usual "a couple of years ago they said eggs were unhealthy, and now they say we should eat 5 per day". And the effect is that people stop trusting the recommendations of the experts.

[–] ashe@lemmy.starless.one 14 points 1 year ago

https://doi.org/10.1093/mnras/stad2032

I wasn't able to read the actual paper since it's behind a paywall, but it's not exclusively a TL model. They say this in the abstract:

Deep space observations of the James Webb Space Telescope (JWST) have revealed that the structure and masses of very early Universe galaxies at high redshifts (⁠z∼15), existing at ∼0.3 Gyr after the BigBang, may be as evolved as the galaxies in existence for ∼10 Gyr. The JWST findings are thus in strong tension with the ΛCDM cosmological model.

While tired light (TL) models have been shown to comply with the JWST angular galaxy size data, they cannot satisfactorily explain isotropy of the cosmic microwave background (CMB) observations or fit the supernovae distance modulus vs. redshift data well.

We present a model with covarying coupling constants (CCC), starting from the modified FLRW metric and resulting Einstein and Friedmann equations, and a CCC + TL hybrid model. They fit the Pantheon + data admirably, and the CCC + TL model is compliant with the JWST observations. [..] One could infer the CCC model as an extension of the ΛCDM model with a dynamic cosmological constant.

[–] SakaiSama@sh.itjust.works 6 points 1 year ago (2 children)

The idea of evolving fundamental constants is pretty mind blowing to me. Is this a well based theory?

[–] 1bluepixel@lemmy.ml 19 points 1 year ago* (last edited 1 year ago) (1 children)

I mean, it's a bold idea, but I don't find it so shocking.

It's well possible that what we call a "fundamental" constant is a variable that depends on other deeper variables. For instance, an earth-bound observer might consider acceleration in freefall to be a constant, but knowledge of universal gravitation tells us it's a variable that depends on the masses of the objects involved and distance between them.

It makes sense that other ostensible "fundamental constants" are also dependent on the structure of the universe at any given point in space and time, but the limited window of our observations makes them appear as constants.

[–] SakaiSama@sh.itjust.works 1 points 1 year ago (1 children)

Sure, but I wouldn’t call gravitational acceleration on earth a fundamental constant, since it’s only locally useful. If something like the charge on an electron started changing though, then there would be profound consequences on the way the universe works

[–] 1bluepixel@lemmy.ml 2 points 1 year ago

I don't disagree; I was using g as an example of a variable that appears constant under a specific set of circumstances. Obviously the charge of an electron is much more consistent.

[–] ProcurementCat@feddit.de 1 points 1 year ago

Well, yeah. We know for example that the coupling constant of the strong, weak and electromagnetic interactions are "running", i.e. they change depending on what energies the interacting particles have.

https://www.physicsmasterclasses.org/exercises/keyhole/en/projects/running_alphas.html

That's why we assume that those interactions are all part of one single, more fundamental interaction at very high energies. We already know that the electromagnetic and weak interaction combine into a single interaction at high energies, and it looks like the strong interaction will combine with that at even higher ones.

This doesn't say anything about how those couplings change with (cosmological) time, however.

[–] CaptObvious@lemmy.world 25 points 1 year ago (1 children)

Interesting hypothesis -- and totally outside my wheelhouse. I wonder how "tired light" sheds energy without violating the law of conservation of energy. Are they suggesting that our universe is not an isolated and closed system?

[–] Foggyfroggy@lemmy.world 17 points 1 year ago* (last edited 1 year ago) (3 children)

No, nothing like that. Everything is within our universe. He says he has a new way of describing light where it loses energy over time (something weird) and so it explains redshift. His idea says the redshift is wrong and the universe is older. He also says universal constants can change (something never observed before that would fundamentally change physics) and he can explain dark matter.

So, a lot of over-the-top claims. I’m pretty sure this guy isn’t toppling physics today as the bar is set high for whatever evidence he is sharing.

[–] jalda@sopuli.xyz 7 points 1 year ago (1 children)

and he can explain dark matter.

* dark energy. They are not the same.

[–] Foggyfroggy@lemmy.world 10 points 1 year ago

I think Dark Einstein showed DE=dmC^2

[–] h34d@feddit.de 3 points 1 year ago* (last edited 1 year ago)

He says he has a new way of describing light where it loses energy over time (something weird) and so it explains redshift.

From what I understand, the main idea behind tired light isn't particularly weird, it's just that scattering could potentially lead to a redshift as well. The issue is that if you assume enough scattering to explain cosmological redshift you would also get some other effects, which are however not observed. This basically ruled out the original tired light theory by Zwicky from the beginning. The author of this paper seems to try to get around that by combining a smaller amount of "tired light" with time-varying couplings. Unfortunately the paper is behind a paywall and I can't tell any more details.

He also says universal constants can change (something never observed before that would fundamentally change physics)

No, he says that coupling constants (not sure if that is what you mean by "universal constants" or not) can change, which is a generic consequence of the RG and has in fact been observed in nature (e.g. electron charge or strong coupling, to name just the most famous examples). From a QFT perspective, the cosmological constant is also a coupling, and several quantum gravity theories do in fact generically predict or suggest a time-varying cosmological constant. So this part by itself isn't really that out there, nor that original for that matter. However, since I can't access the paper I can't judge whether the author's way of varying Λ is reasonable or just a way to fit the data without any physical motivation, and I don't really know what the article means by "he proposes a constant that accounts for the evolution of the coupling constants".

and he can explain dark matter

That seems like a more grandiose claim to me, if accurate. Do you have a source for where the author claims that? Although he wouldn't be the first to do so.

I’m pretty sure this guy isn’t toppling physics today as the bar is set high for whatever evidence he is sharing.

I think this can be said for a lot of popular science article with topics like this. However, in many cases the blame can lie more with the pop-sci journalists who are looking for a cool story and might over-interpret the author's claims (I guess "physics toppled!!!11" sounds more interesting than "some guy suggests that some data might be fitted in a slightly different way"). Although in this case at least the age of the universe claim does seem to come from the author.

Edit: Judging by another article of the author someone else linked me to further down, it seems that while the author does speak of coupling constants, he really does refer to time-varying fundamental constants. So I must agree with the previous poster on this, it does seem quite a bit more out there than I had originally assumed.

[–] Blamemeta@lemmy.world 0 points 1 year ago (2 children)

Isn't dark matter just matter we can't percieve? Rogue asteriods and the like? I admit its been a minute since I studied this stuff, but dark matter isn't very special.

[–] Foggyfroggy@lemmy.world 5 points 1 year ago

It’s been a minute, but the universe is expanding and the speed of the expansion depends on the total gravity. When we calculate the amount of mass it would take to make that much gravity, it’s way more than what we actually see out in the universe. It’s really a cheeky way of saying our current model makes tons of good predictions so we trust that something is out there, but in reality we don’t know its nature and can’t detect or measure it directly.

[–] jalda@sopuli.xyz 2 points 1 year ago

Things like asteroids, galactic dust and the like are already accounted for in the baryonic (ie ordinary) matter. We can estimate it for example measuring the absorption of different wavelengths of light, or extrapolating the local abundance of asteroids. There are theories like the MACHO that propose that we are missing some, but in general it is understood they can only account for a tiny fraction of the missing mass.

The predominant hypothesis is that dark matter is composed by some unidentified particles, that have the same thermodynamic properties as usual matter (basically that their energy is proportional to the volume), but that don't interact (or interact very weakly) with normal matter.

[–] query@lemmy.world 19 points 1 year ago (2 children)

It used to be 13.7 billion years+- a big margin that got narrowed down to 13.8+- a smaller margin. Not seeing that changing unless there's something seriously wrong with the previous research.

[–] Clent@lemmy.world 11 points 1 year ago (1 children)

Narrowing it based on what we can measure doesn't mean it's correct.

The deeper we have stared into the universe the more our base understandings have challenged.

[–] bitcrafter@lemmy.sdf.org 2 points 1 year ago

Hence the "unless there's something seriously wrong with the previous research" part. That is always a possibility, of course, but it's much less likely that is the case then that this single study is the thing that is wrong.

[–] Foggyfroggy@lemmy.world 4 points 1 year ago

More likely it’s this guy’s research.

[–] howdy@thesimplecorner.org 8 points 1 year ago

So insane man, love it. Hard to comprehend and just to think about.

[–] IamLost@lemmy.world 6 points 1 year ago

What about what the CMB tells us? Theory seems to ignore that entirely. I'll wait for the cosmic neutrino background before I take any of these articles more seriously.

[–] moridinbg@lemmy.world 6 points 1 year ago (3 children)

Are there any constants that we actually know to have varied along the lifetime of the universe?

[–] rhokwar@lemmy.world 2 points 1 year ago (1 children)

I don't know if this counts as a constant, but I read that time moved something like 5 times slower in the early years of the universe.

[–] vimdiesel@lemmy.world 6 points 1 year ago

It didn’t as time is relative just like space. There is no absolute standard of time to say “time moves faster”. Faster relative to what?

[–] Contramuffin@lemmy.world 2 points 1 year ago* (last edited 1 year ago) (1 children)

Somewhat. Based on my understanding of current astronomy news (I'm not an astronomer, just interested in the field) it's not proven, but it's not entirely disproven either. For instance, my understanding is that the Hubble constant (rate of expansion of the universe) is different if measured with the Cosmic Microwave Background (newer universe) compared to measuring redshirt of stars (older universe). Of course, it could be that one of the measurements made an assumption that's not true, but i don't think it's out of the question that the false assumption ends up being that the constant stays the same over time...

Take what I say with a grain of salt, though. Hopefully an actual astronomer can pitch in

[–] jalda@sopuli.xyz 1 points 1 year ago

"Hubble constant" is a misnomer, and an old fashioned term. Cosmologist actually use the term "Hubble parameter" (which is in general time dependent except in very specific models which only contain dark energy), and denote its present value as H~0~.

https://en.wikipedia.org/wiki/Hubble%27s_law#Time-dependence_of_Hubble_parameter

[–] h34d@feddit.de 2 points 1 year ago* (last edited 1 year ago) (1 children)

According to my understanding, yes. For example, it is usually assumed that there was a period of time shortly after inflation when matter was in a quark-gluon plasma, which would imply a larger strong coupling than today, since a small strong coupling is associated to confinement. There was also the electroweak-epoch, during which the electromagnetic and weak interactions were unified, and the corresponding gauge bosons were massless. The masses of the W and Z bosons can thus also be regarded as time-varying, as well as the electron charge. However, it should be noted that these changes are not all that significant on the cosmological scales under investigation here (e.g. the quark epoch ended at about 10^-6^ seconds after the big bang, which is much much less than the age of the universe, and it's assumed that it still took quite a while before the first stars formed). A time-varying cosmological constant could potentially be much more relevant (and some quantum gravity theories even predict it), and I've heard some people suggesting it as a potential solution for the H0 tension. However, I unfortunately can't access the paper and assess what precisely the author did there, and whether it is in any way similar to what I just mentioned.

[–] jalda@sopuli.xyz 2 points 1 year ago (1 children)

What you're talking about is the energy dependence of the coupling constants, which is a phenomenon that is very well understood theoretically, and also checked in experiments. The early universe was much hotter, and thus particles had much more kinetic energy and "felt" slightly different coupling constants. The neat thing is that, since this is a purely energy-dependent effect, we can recreate the conditions of the early universe: the collisions at LHC have an energy of the order of 1 TeV, which corresponds to a temperature of 10^16^K, the temperature 10^-12^ s after the Big Bang. Anything after the first 10^-12^ s we can directly recreate, and from 10^-12^ s to about 10^-30^ s-ish we can more or less reliably extrapolate. And of course this is all included in the standard Lambda-CMD cosmology.

Although the article is behind a paywall (which is somewhat strange in cosmology, but I digress), you can check other articles by the same author that also use the "varying constants" framework, for example https://arxiv.org/abs/2201.11667. His framework is that the speed of light c, the Planck constant h, the Boltzmann constant k and the Gravitational constant G depend directly on time, or to be more precise, on the expansion factor of the universe. There are two big differences with respect to what you were saying:

  • c, h and k are not coupling constants, and therefore they don't receive any energy-dependent corrections. In fact, you could think of these constants as "conversion factors" between units: c converts space-time coordinates in seconds to space-time coordinates in meters, k converts kinetic energy in Joules (or electronvolts) to kinetic energy in Kelvin, and h converts angular momentum or action measured in quanta to angular momentum or action measured in J·s (or eV·s). Honestly it doesn't make much sense to me that these constants could change (what does it means, in physical terms), that they could change in a correlated way, or that they could change in a correlated way to one, and only one, coupling constant, G.
  • Since this is a time-dependent change, there is no real way to significantly test the hypothesis (unlike the energy-dependent changes). We can not go back in time, or to wait to a different time when these constants would be different. He actually proposes to study how the experimental determinations of these constants in the last 10-20 years, which sounds very wild, as those tiny differences are very susceptible, by definition, to experimental uncertainties, and they are not very suitable for controlled tests.
[–] h34d@feddit.de 1 points 1 year ago

Thanks for giving additional explanation. I was trying to keep my reply relatively short and agree with most of what you said.

Although the article is behind a paywall (which is somewhat strange in cosmology, but I digress), you can check other articles by the same author that also use the “varying constants” framework, for example https://arxiv.org/abs/2201.11667. His framework is that the speed of light c, the Planck constant h, the Boltzmann constant k and the Gravitational constant G depend directly on time, or to be more precise, on the expansion factor of the universe.

Thanks for the arxiv link. I was aware that some people did stuff like this (time-varying fundamental constants), but the abstract only speaking of "coupling constants" made me think of Λ (and G), not fundamental constants. There are some theories that motivate a varying speed of light, for example (Hořava–Lifshitz gravity comes to mind), but this doesn't seem to be motivated by any theory in particular, as far as I can tell. I also agree with you that it seems quite weird to give c, h, and k a time dependence each, only to then have them all be functions of G.

Since this is a time-dependent change, there is no real way to significantly test the hypothesis (unlike the energy-dependent changes).

I'm not sure if I fully agree with this. Shouldn't varying c, h, and k with time clearly change any observable related to the dispersion of light and gravitational waves, or black body radiation (among many other things)? And if we had access to even just one of those from different times during cosmological evolution (where the change should be much larger than between a few decades in the present), we should in principle be able to check if the proposed scaling law holds quite easily. Of course, the author could always make the variation with time small enough to avoid contradicting experiment (which would make it indeed unfalsifiable in practice), but that seems to go against the main idea of using these time-varying fundamental constants to explain some aspects of cosmological evolution. My guess now would be that the paywalled paper modifies the relation between redshift and time to undo the "damage" done by modifying the constants. Nevertheless, it wouldn't surprise me much if this kind of scaling is already ruled out implicitly by some data, as I can't imagine it not affecting a lot of different observables, but maybe I'm also overestimating the experimental cosmological data available at present, or the strength of the variance the author proposes.

[–] marci4@discuss.tchncs.de 5 points 1 year ago

Exited for more news

[–] Got_Bent@lemmy.world 3 points 1 year ago

I've been watching progressively more complex videos on YouTube about spacetime over the past two years.

The more I understand of it, the more I realize I understand nothing of it.

It bends my mind so much, it's like taking weed without any physical substances.

It makes the Total Perspective Vortex seem like a walk in the park.

[–] vimdiesel@lemmy.world 2 points 1 year ago

A lot of theories come along, few survive scrutiny of people who know what they’re doing

[–] hungry_freaks_daddy@lemm.ee 0 points 1 year ago* (last edited 1 year ago) (4 children)

I’m not surprised at all honestly

It sounds insane to say, but 13.4 or whatever felt way too young

[–] vimdiesel@lemmy.world 11 points 1 year ago (1 children)

“Feels” and “common sense”means little in science unless you have a mathematical or logical reason why you feel that way. I’ve seen far too many metaphysical theories try to be taken seriously to not point out that “feels” is useless, observation and math are what matter

[–] hungry_freaks_daddy@lemm.ee -4 points 1 year ago (1 children)

And yet, some of the greatest scientific discoveries of all time were made based on people’s feelings and intuition. Fucking shocker I know right. I’ll bet you’re fun at parties.

[–] Buddahriffic@lemmy.world 2 points 1 year ago

Despite agreeing with your initial position, you sound like an asshole at parties and outside of them, too. If you need to posture and belittle to support your position, then you have no business trying to argue it in the first place.

Intuition can be a powerful compass to guide us to truths we haven't yet considered, bubbling up from our subconscious that contains the bulk of our brain's processing power. But the other commenter is right, it's not infallible. That same intuition in different people came up with all of science's knowledge (both the stuff that is currently believed and the stuff that has since been disproven) as well as all of religion's knowledge (assuming there isn't any higher being involved, which my intuition says there isn't but others' have come to different conclusions).

[–] Ultraviolet@lemmy.world 1 points 1 year ago

Double that is still weird. If the heat death of the universe is 10^100 years out or more, we're incredibly early whether it's 13 billion or 26 billion. That leads to one possible explanation for the Fermi paradox, the universe will have countless civilizations rise and fall over the eons, we're just one of the first, if not the first.

Granted that's just a thought that came to mind under the influence of an unexpectedly strong edible rather than actual scientific research, but it's still neat.

[–] Knusper@feddit.de 1 points 1 year ago

Well, it would be most logical for it to have existed forever.

For the last 13.7 billion years, we haven't observed matter/energy just popping into existence. In all that time, nothing was truly created from scratch.

So, it would be quite the exception to the rule, if that was different beforehand...

[–] lemmyshmemmy@lemmy.world -1 points 1 year ago

A sincere thank you for a fascinating, quality post in Technology instead of the usual Threads/Twitter/Reddit posts.

[–] A_A@lemmy.world -3 points 1 year ago

Before Hubble and also before JWST scientists predicted these telescopes would :
Hypothesis : show evidence of the beginning of the universe at about 14 billion years.
Observations again and again nulifies that hypothesis.
Scientist goes over the top about this in part because they have :

human needsneed to publish, need to make a career, need to be recognized as scientists, need to put bread on the table


And so they come up with this :
BigBang, acceleration of the expansion : "inflation of the universe", decceleration : "end of the inflation", and now a new phase of acceleration !
Since there is not enough strong non-contradictory evidence to say otherwise, let's go with Ocam's razor : whatever more simple theories, even if it hurts scientist's egos.

load more comments
view more: next ›