Dark energy does not exist, some scientists have claimed – which could help get rid of one of the universe's biggest mysteries.
For a century, scientists have thought that the universe was expanding in all directions. To make that assumption work, astronomers have used the concept of dark energy.
Dark energy cannot be seen directly and has never been proven. But scientists have suggested that it must exist because of the effect is seemingly exerts on the universe and as it is needed to help resolve some fundamental problems in our understanding of the cosmos.
Now, however, researchers from the University of Canterbury say that the universe is not actually expanding equally in all directions. Instead, it is growing in a "lumpier" way, in more varied directions.
[...] "Dark energy is a misidentification of variations in the kinetic energy of expansion, which is not uniform in a Universe as lumpy as the one we actually live in.
[Source]: The Independent
[Abstract]: Supernovae evidence for foundational change to cosmological models
Monthly Notices of the Royal Astronomical Society Letters.
(Score: 4, Touché) by driverless on Sunday January 05, @08:31AM (16 children)
After dark matter you mind having a look at string theory next? Physics has plenty more after that, but string theory would be the next biggest one.
(Score: 4, Informative) by Lester on Sunday January 05, @09:19AM (3 children)
Strings theory is not yet even a hypothesis.
They are still trying to build a coherent math construction. Let alone proposing any experiment for the physical world to probe or refute it.
(Score: 4, Funny) by aafcac on Sunday January 05, @03:42PM (2 children)
It's not even a theory it's a fact, I've got an entire drawer full of strings and I can assure you they're very real.
(Score: 5, Funny) by Gaaark on Sunday January 05, @07:16PM
You probably have 26 imaginary drawers full, but you just can't imagine them!
--- Please remind me if I haven't been civil to you: I'm channeling MDC. ---Gaaark 2.0 ---
(Score: 3, Funny) by pTamok on Monday January 06, @01:06PM
But some of those strings are stored in drawers that are too small to be perceived.
(Score: 2, Interesting) by Anonymous Coward on Sunday January 05, @03:09PM (11 children)
They are talking about dark energy. Dark matter is something else entirely.
(Score: 1, Interesting) by Gaaark on Sunday January 05, @07:18PM (10 children)
And JUST as non-existant.
--- Please remind me if I haven't been civil to you: I'm channeling MDC. ---Gaaark 2.0 ---
(Score: -1, Troll) by Anonymous Coward on Sunday January 05, @09:56PM
Jeez if we could have installed you as President we could save on all that boring research and just get told the answer.
(Score: 2) by PiMuNu on Monday January 06, @09:01PM (8 children)
Faith-based statements have only a weak role in scientific discussions.
(Score: 2) by Gaaark on Monday January 06, @09:27PM (7 children)
And science based on "We must do ANYTHING just in order to save GR, even to the point where we make up mass we cannot find, despite spending years and years and millions/billions of dollars looking for" is not science: it is also faith.
Faith that GR is not wrong, so we must do whatever we need to do to save it.
I'm looking for answers through the Scientific Method, not "We must save GR no matter what". That is like faith: "God exists despite finding zero evidence".
--- Please remind me if I haven't been civil to you: I'm channeling MDC. ---Gaaark 2.0 ---
(Score: 2) by PiMuNu on Tuesday January 07, @08:52AM (6 children)
> "We must do ANYTHING just in order to save GR, even to the point where we make up mass we cannot find, despite spending years and years and millions/billions of dollars looking for"
Why do you assert that any science is being done based on this statement?
(Score: 2) by Gaaark on Tuesday January 07, @02:02PM (5 children)
NO 'science' is being done on the basis of this statement! Dark Matter was created out of thin air because GR was wrong:
According to GR, galaxies, with the mass we know about, are spinning so fast that their gravity isn't enough to hold them together. They should be spinning apart instead of just spinning and staying together.
So, instead of looking at it with the Scientific Method (the scientific method involves making conjectures (hypothetical explanations), predicting the logical consequences of hypothesis, then carrying out experiments or empirical observations based on those predictions), they said "GR can't be wrong, so there must be some imaginary stuff there that creates mass we cannot detect".
So they went out and started spending oodles of time and money looking for the imaginary stuff.
I high-lighted 'predicting', because DM predicts nothing: there is no formula that is applicable. Each galaxy must have DM applied to it in random ways in order to hold THAT galaxy together.
It is all a little too 'hand-wavy' for the scientific method.
On the other hand, theories such as QI HAVE a formula, can be applied to EVERY galaxy (no hand-waving or unicorns) and match with GR perfectly WITHOUT Dark Matter.
Dark matter should be dropped (with the properties they have given DM, it CANNOT exist, because binary stars exist. DM cannot explain binary stars) and NEEDS to be dropped so other, better theories can rise up.
Dark matter, for me, is like Galen's theories of bile, blood and phlegm which kept back real medical science for over 1000 years.
-- https://en.wikipedia.org/wiki/Galen [wikipedia.org]
Anyone with a different (read: True) theory was laughed at. "Who are you against the great Galen?" for centuries until FINALLY things changed.
DM is not science. It is faith and where the money is... lately, though, the cracks have been showing and maybe soon, FINALLY, things are changing
--- Please remind me if I haven't been civil to you: I'm channeling MDC. ---Gaaark 2.0 ---
(Score: 3, Informative) by PiMuNu on Tuesday January 07, @05:50PM (2 children)
> theories such as QI HAVE a formula, can be applied to EVERY galaxy
I have never seen a modified gravity that can survive the observational data. Note that anomalies in gravitational effects on long distances are not only found in galactic velocity curves; anomalies are also found in a number of other observations, for example the evolution of anisotropies in the Cosmic Microwave Background and anomalies in the formation of clusters of galaxies (Press-Schechter).
> there is no formula that is applicable
If you need a formula, the Standard Model Lagrangian exists. Many modifications of the SM Lagrangian do indeed provide observable phenomena.
It is true, there are some modifications to the SM Lagrangian that do not provide observable phenomena with any known technology but would yield the observed gravitational anomalies. Nature may have chosen this universe for us to live in unfortunately (it may be there is some as-yet undiscovered Modified Gravity theory that makes the observables, I am not trying to prejudice that discussion).
> DM cannot explain binary stars
This is a rather strange statement. What is the justification?
(Score: 2) by Gaaark on Tuesday January 07, @07:06PM (1 child)
Sorry, old person brain fart: should have said "Wide binaries"
An easy google find from the home of QI -- https://physicsfromtheedge.blogspot.com/2018/09/wide-binaries-20.html [blogspot.com]
--- Please remind me if I haven't been civil to you: I'm channeling MDC. ---Gaaark 2.0 ---
(Score: 2) by PiMuNu on Wednesday January 08, @02:12PM
I did a bit of digging about wide binaries. It looks like there is since 2016 a much bigger dataset of wide binaries than the one referenced by the author in your reference. I am not knowledgeable enough to really judge, but I note that these authors do not find strong significance with MOND. They did not check QI.
https://arxiv.org/abs/2205.02846 [arxiv.org]
FTFA (Conclusions):
"The fitting results show a clear preference for Newtonian
gravity over MOND, with a high formal significance;"
"this conclusion is only tentative at present due to using
a somewhat over-simplified maximally-random model for
the triple population. Further studies are clearly needed..."
(Score: 2, Insightful) by pTamok on Tuesday January 07, @06:50PM (1 child)
Umm. No.
General Relativity is not necessarily wrong, but it rather depends on your definition of 'wrong' (shades of Bill Clinton [wesaythedarndestthings.com] here).
General Relativity is a very successful model of the universe as we see it. It describes many observations (Aristotle) and passes many experimental tests (Roger Bacon, and others) - but, as you correctly point out, there are some observations it does not explain, according to our current understanding. So you can say it is WRONG, or perhaps inaccurate or incomplete, just as Newtonian physics, which describes planetary orbits extremely well so long as the planet is far enough away from the Sun, is either WRONG, or requires relativistic modifications/adjustments for Mercury. Newton wasn't wrong, in my opinion, just incomplete: and it is entirely possible that Einstein's General Relativity is not WRONG, but, in the same manner as Newtonian physics, incomplete.
I don't thing equating 'wrong' with 'incomplete' is necessarily helpful, but you might have a different view.
The thing is, any competing description of the universe needs to describe the behaviour of universe at least as well as General Relativity - and competing theories/models currently simply do not.
This work from the University of Canterbury, NZ gives a way of reconciling our current astrophysical models using General Relativity to apparently describe the expansion of the Universe in a way that is at least as good as 'Dark Energy', but without using the idea of Dark Energy. If my understanding is correct (and it could well not be), it seems quite elegant. It does not explain Dark 'Matter', which is the postulated solution to the problem you describe of the rotation profile of galaxies.
Let me quote the Wikipedia article on Dark Matter [wikipedia.org]:
It is helpful not to confuse Dark Energy and Dark Matter. We do not, currently, have an objectively better theory/description of the behaviour of the Universe than General Relativity. Lots of people are working on it. Note that there are a number of well-known unsolved problems in physics [wikipedia.org] - this does not mean that physics is wrong, but that our description of the Universe is incomplete, because, for the most part, our models make very good predictions that accord with experimental tests and describe observations - it is basically at the margins that things get interesting.
(Score: 2) by Gaaark on Tuesday January 07, @07:15PM
Sorry: another brain fart. I tried to not say wrong but instead say not complete and failed.
It IS like Newtonian physics.
This is why i like QI (although i am not married to it, just like i was once excited about GR but now am not): it has a formula that explains away DM and holds with GR quite well while also involving the quantum world.
--- Please remind me if I haven't been civil to you: I'm channeling MDC. ---Gaaark 2.0 ---
(Score: 5, Informative) by Adam on Sunday January 05, @02:11PM (1 child)
https://bigthink.com/starts-with-a-bang/lumpy-explain-dark-energy/ [bigthink.com]
(Score: 1) by pTamok on Tuesday January 07, @07:44PM
Thank you, that was an interesting read - polite, but pretty devastating. It would be interesting to read the defence.
(Score: 4, Interesting) by VLM on Sunday January 05, @04:13PM (2 children)
Asking the question of "what is dark energy" is a fun litmus test.
There's no astrophysical disproof or discontinuity or disagreement that I'm immediately aware of that "God is everywhere and is larger than the known universe and interacts with all of it all the time, which seems to be resulting in a large scale peculiar gravitational motion effect". God has a measurable mass might trigger some religious folks under some conditions. It's pretty funny how you can take almost any discussion of "Dark Matter" or "Dark Energy", especially the worst hand wavy popular science screeds about it, and just replace the phrase with "Omnipresent God" and the scientific/mathematical discussion is more or less unchanged.
The same line above makes the atheist types VERY VERY VERY triggered and intensely hateful, always a good strategy for 'scientific' research LOL, then they jump thru all kinds of insane hoops and wild sophistry to avoid the obvious, yet personally unacceptable to them, conclusion.
I think the dudes in the article are more the agnostic POV where if the assumptions and the numbers look ridiculous, and if we assume the numbers are correct (why?), then the assumptions must be wrong, such as perfectly smooth expansion, which was assumed for no real reason to begin with beyond the simpler theory is more likely to be correct. Personally, I more or less agree with these guys, although I'm sympathetic to the 1st above and I LOL at the triggered folks in the 2nd above. Generally, what I've found works pretty well, is if you have a large system with a lot of inputs and a lot of "internal processing" going on, and the modeled results don't match reality, usually the simplest solution is your simulation inputs are in error or you have a bug in your code/design, making up elaborate justifications of additional nonsense just to fix the bug is traditionally a fools errand.
(Score: 0) by Anonymous Coward on Monday January 06, @03:32PM (1 child)
(I) Galaxies are accelerating away from eachother.
(II) F = M A.
You do the rest.
(Score: 2, Interesting) by pTamok on Monday January 06, @04:47PM
1) How do you measure the acceleration?
2) To get the number you measure in (1), what assumptions are you making about (a) the homogeneity of space and (b) the passage of time as measured in different regions of space that could be at different gravitational potentials with respect to each other?
We can see the effects of gravitation on the passage of light, not least because of the observation of the existence of gravitational lenses [wikipedia.org]. We can also determine experimentally that time runs at differing rates in differing gravitational potentials [wikipedia.org].
This means there is a basis for saying that the difference in the rate of passage of time in different parts of the universe, which is not homogenous, even at large scales [wikipedia.org], could be significant: and this research makes the claim that it is, and fits observational data better than the dark energy postulate.
This summary of the work might well explain it better than me:
Science Alert: Dark Energy May Not Exist: Something Stranger Might Explain The Universe [sciencealert.com]
(Score: 4, Insightful) by mcgrew on Sunday January 05, @07:35PM (3 children)
Dark energy and dark matter are called "dark" because we don't understand the effects they cause. Good luck explaining that to someone with a journalism degree obtained with no science classes.
This new theory does go quite a way towards explaining dark energy. I wonder, can it be tested?
My own wild ass ignorant guess is that the galaxies are all solar sails, and photon pressure is pushing them apart. Dark matter could be clouds of neutrons, with no electrostatic force to bring them into a mass.
I have a hard time swallowing mainstream media's science reporting. The reason the media called the Higgs bosun the "God particle" is because a journalist asked a scientist (Higgs? I've forgotten) what they called the elusive particle. The answer was "That God damned particle." His editor removed the horribly vulgar word "damned" like it was 1939 and he was editing a review of Gone with the Wind.
A man legally forbidden from possessing a firearm is in charge of America's nuclear arsenal. Have a nice day.
(Score: 0) by Anonymous Coward on Sunday January 05, @09:58PM
It proves science is a global conspiracy to suck graaaaaaaant money muahhahahahaa!!
(Score: 3, Insightful) by weirsbaski on Monday January 06, @09:13AM (1 child)
I thought it was even more basic than that- dark energy / dark matter don't give off EM radiation, so our usual first-check method of looking for them with telescopes comes up empty?
(Score: 3, Informative) by PiMuNu on Monday January 06, @01:17PM
> don't give off EM radiation
don't interact with EM force at all (just like neutrinos, they are 0 charge)
(Score: 1) by pTamok on Monday January 06, @01:15PM
I must admit, the idea is appealing to me: the idea that time runs at different rates in different parts of the Universe because they are at different relative gravitational potentials. It sounds very plausible, and smacks of replacing the 'spherical cow' (uniform expansion and/or uniform density as a simplification) with a more complicated model that re-uses existing, well-tested concepts.
I do not know enough to be able to look at the mathematics/astrophysics myself to make a sensible evaluation of whether this is good work or not. I'm slightly embarrassed by that. It could just be hand-wavy sleight of hand, sounding as plausible as an LLM.
I'd love to see some educated layperson-accessible comment from people who actually understand and work with this stuff to comment on the plausibility.