New research: Dark Energy might not exist after all

https://phys.org/news/2019-11-evidence-anisotropy-cosmic.html

by BurningFrog • 7 years ago

123 31 7 years ago

phys.org

ncmncm2• 7 years ago

So, "never mind" the supposed 70+% of the universe's mass-energy, now attributable entirely to local motion?

Who awards these Nobel Prizes, anyway?

(My first thought when I heard about this Dark Energy thing was, "which part of Occam's Razor don't you get?")

iamaelephant• 7 years ago

(My first thought when I heard about this Dark Energy thing was, "which part of Occam's Razor don't you get?")

Well, you would know.

knzhou2• 7 years ago

It was an application of Occam's razor. Dark energy arises automatically in the Standard Model. That is, you don't put it in by hand -- it emerges no matter what you do. In fact, we often get too much of it; this is the cosmological constant problem.

The_rationalist• 7 years ago

MOND is epistemologically far stronger.

Cougher2• 7 years ago

Occam's Razor is not a law.

dang2• 7 years ago

"Please don't post shallow dismissals, especially of other people's work. A good critical comment teaches us something."

https://news.ycombinator.com/newsguidelines.html

ncmncm2• 7 years ago

This is not a dismissal. The work posted is important.

empath753• 7 years ago

https://physicsworld.com/a/dark-energy-debate-reignited-by-c...

According to this article, using the model from this paper with more up to date data sets completely reverses their results.

chime• 7 years ago

Yeah, r/physics doesn’t have a good opinion of this either: https://www.reddit.com/r/Physics/comments/e01bxe/dark_energy...

I would love to see a PBS SpaceTime video explaining all of this. They do a fantastic job with new papers such as this one.

jbotz3• 7 years ago

Sorry, but the article you linked says nothing about "reversing the results" of the OP article, it is about the same research as the OP article... Which at best you might say reverses the results from the 90s which originally found acceleration of cosmic expansion.

empath753• 7 years ago

According to Riess, however, the supernovae data used by Sarkar’s group are out of date. He says that he and some colleagues, including D’Arcy Kenworthy of Johns Hopkins University, plugged data from a sample of about 1300 supernovae with lower systematic uncertainties into the model used in the latest work. The results, he says, were unambiguous, with the existence of a dipole rejected at more than 4σ and cosmic acceleration confirmed at over 6σ.

More importantly, says Riess, the objections against Sarkar and colleagues’ original statistical analysis still stand, as do the criticisms of neglecting other data. “The evidence for cosmic acceleration and dark energy are much broader than only the supernovae Ia sample, and any scientific case against cosmic acceleration needs to take those into account,” he says.

joe_the_user• 7 years ago

OK, looking at the comments, I have to note that Dark Matter[1] and Dark Energy[2] are two different but related hypotheses. The basic existence of Dark Matter is on a fairly strong footing experimentally and afaik this article doesn't cast doubt on its existence (it has been observed, on the cosmic scale, as accurately as many form ordinary matter, for example). Again, this is the dark energy issue. Just sayin'

[1] https://en.wikipedia.org/wiki/Dark_matter [2] https://en.wikipedia.org/wiki/Dark_energy

mikhailfranco• 7 years ago

'Dark Matter' is physicist code for: gravitating stuff that we cannot see.

'Dark Energy' is physicist code for: anti-gravitating non-stuff that we cannot see.

(i.e. Dark Energy, aka Einstein's Cosmological Constant, is a property of the vacuum.)

gus_massa• 7 years ago

Another important difference is that:

Dark Matter is not uniformly distributed, for example if forms big blobs that surround the visible parts of the galaxies.

Dark Energy is uniformly distributed, but the (equivalent?) density is very small, so the effect is important in the very empty space between galaxies.

astro123• 7 years ago

Not to go into much detail, but these author's views are not shared broadly in the cosmology community. There was a recent paper [1] put on the arxiv that talked a bit about this. I'm not an expert on supernova cosmology (I work on cosmology using other methods) but people I know who are experts claim there are issues.

There are also a ton of other reasons to think that the universe is flat (see the CMB [2]) and to think that there is dark energy (large scale structure [3]).

We still have no idea what DE is and it might not be an "Energy" but rather some modification of gravity or something else. But we're pretty confident in the phenomenology - there is something there that appears to be pulling things apart.

[1] https://arxiv.org/pdf/1911.06456.pdf [2] https://physics.stackexchange.com/questions/439535/why-does-... [3] https://www.darkenergysurvey.org/supporting-science/large-sc...

1e10• 7 years ago

So if the universe is flat does that make the earth flat as well? :-D

badrabbit2• 7 years ago

It's a matter of perspective. It is certainly not flat from the perspecticve of our 5 basic senses.

Shorel• 7 years ago

I think it is flat in the sense that our 3D space has no curvature beyond the provided by gravity.

Of course this is totally different than saying it is 2D flat. We know this because of cats.

tanilama• 7 years ago

It might exist it might not exist.

Papers published anyway.

knzhou2• 7 years ago

A paper containing only things we already knew for sure is not a real scientific paper at all.

It's easy to sit back and feel smug because physicists might be wrong -- but it's impossible to do anything worthwhile without taking on that risk.

_of• 7 years ago

A paper containing only things we already knew for sure is not a real scientific paper at all.

It could be. Confirming results is part of the scientific process.

Cougher2• 7 years ago

Before these people waste too much time trying to disprove dark energy, they ought to visit my ex.

teksimian• 7 years ago

Sorry, You have to go back.

dang2• 7 years ago

Please don't do this here.

LessDmesg• 7 years ago

As my physics lab teacher taught us, all breakthroughs in physics happen after new better measuring instruments become available. Modern cosmology is starved of such new equipment, hence devoid of any real progress, having to wallow in theoretical bogmires instead. I would suggest all those funds and scientists be instead diverted to researching nuclear fusion, which is the more pressing goal for humanity right now.

New research: Dark Energy might not exist after all

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