However, a team of astronomers at Yonsei University have now put forward new evidence that type Ia supernovae, long regarded as the universe’s "standard candles", are in fact strongly affected by the age of their progenitor stars.

Even after luminosity standardisation, supernovae from younger stellar populations appear systematically fainter, while those from older populations appear brighter.

Based on a much larger host-galaxy sample of 300 galaxies, the new study confirmed this effect at extremely high significance (99.999% confidence), suggesting that the dimming of distant supernovae arises not only from cosmological effects but also from stellar astrophysics effects.

When this systematic bias was corrected, the supernova data no longer matched the standard ΛCDM cosmological model with a cosmological constant, researchers said.

Instead, it aligned far better with a new model favoured by the Dark Energy Spectroscopic Instrument (DESI) project, derived from baryonic acoustic oscillations (BAO) – effectively the sound of the Big Bang – and cosmic microwave background (CMB) data.

That's somewhat less astonishing, but still a very big deal. I've always had an intuitive soft spot for Big Bounce cosmology--it's just so neat and would wrap up so many things--and it would be cool if the evidence started supporting that.

[–] ChaosMaterialist@hexbear.net 9 points 2 months ago

The correcting of "standard candles" is a huge deal, but only to astronomy nerds. I never particularly liked the accelerated expansion of the universe and the required exotic explanations for it, but until now I was like :cant-prove-it:

[–] fox@hexbear.net 7 points 2 months ago (2 children)

For me the big question is "what about black holes" in a Big Bounce scenario.

[–] theturtlemoves@hexbear.net 6 points 2 months ago (1 children)

... with strange aeons even black holes may die ...

[–] fox@hexbear.net 3 points 2 months ago

If the Big Bounce happens faster than 10^100 years then there will still be black holes, and things falling into a black hole (such as the entire cosmos) would extend its lifespan.

Also, if the universe does eventually Bounce, new black holes will have opportunity to form. Hawking radiation only really starts to come into play when not even photons are hitting black holes any more.

[–] Philosoraptor@hexbear.net 4 points 2 months ago

There's a cosmological model in which the bounce actually takes place inside a supermassive black hole, and I know that some of the folks who like that view were excited about the James Webb results from last year that showed what appears to be a preferred axis of rotation for galaxies. I don't know too much about the view though (I'm a lot more familiar with the small stuff than the big stuff).

[–] TraschcanOfIdeology@hexbear.net 4 points 2 months ago

It figures. Still, as the tools get sharper, the questions get weirder, I feel. when the data is getting more incontrovertible, the more responsibility we have to come up with valid explanations.

[–] Xavienth@lemmygrad.ml 3 points 2 months ago (2 children)

Big Bounce is cool, but heat death isn't such a bad thing after all because - and I'm no astrophysicist - I've always had a pet theory that a universe as complex as ours could emerge spontaneously from a void of nothing given quantum fluctuations and infinite time.

[–] Philosoraptor@hexbear.net 5 points 2 months ago

I think that's the going string theory explanation these days. I like big bounce because it also explains the initial low-entropy state of the universe really elegantly, which gives you all sorts of nice things like the arrow of time.

[–] PolandIsAStateOfMind@lemmygrad.ml 3 points 2 months ago

a universe as complex as ours could emerge spontaneously from a void of nothing

It wasn't complex when it emerged though, all that happened later.

[–] WokePalpatine@hexbear.net 3 points 2 months ago

Yeah, it definitely makes more intuitive sense. Although the thought of possible eternal recurrence is horrifying.