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So they assumed a standard candle stayed the same luminosity throughout its life, when empirical observation appears it fades overtime. This results in a miscalculation of distance, which, when corrected, makes dark energy disappear. How to integrate into the article? Kevin Baas talk 19:33, 7 January 2020 (UTC)
A study published in 2020 questioned the validity of an essential assumption which supports the existence of dark energy, and suggests that dark energy may not actually exist. Lead researcher of the new study, Young-Wook Lee of Yonsei University, said, "Quoting Carl Sagan, extraordinary claims require extraordinary evidence, but I am not sure we have such extraordinary evidence for dark energy. Our result illustrates that dark energy from SN cosmology, which led to the 2011 Nobel Prize in Physics, might be an artifact of a fragile and false assumption." [1] [2]
References
- ^ Yonsei University (6 January 2020). "New evidence shows that the key assumption made in the discovery of dark energy is in :error". Phys.org. Retrieved 6 January 2020.
- ^ Kang, Yijung; et al. (10 December 2019). "Early-type Host Galaxies of Type Ia Supernovae. II. Evidence for Luminosity Evolution in Supernova Cosmology". arXiv. arXiv: 1912.04903v1. Retrieved 6 January 2020.
Standard candles are not the only cosmological measurement that provides evidence for dark energy. There are many other precise cosmological measurements including the cosmic microwave background, baryon acoustic oscillations, large-scale structure measurements, etc. Bringing all of these measurements together is how experts continue to conclude that there exists another form of energy. We should be careful not to amplify sensationalized articles as compared to what is happening within the cosmological research community. Cosmojellyfish ( talk) 02:59, 22 January 2020 (UTC)
I disagree with the basic premise and tone of the above statement. Joseph Silk and co have shown that the concordance of other datasets that make up the evidence for Dark Energy no longer exists.
https://arxiv.org/abs/1911.02087 https://arxiv.org/abs/2003.04935
In any case it's widely acknowledged that other than type 1a supernova Hubble diagram, all other evidence for dark energy is indirect.
https://arxiv.org/abs/1506.05478
Incidentally, it has been discussed back in 1987 itself (by George Ellis and co) that because the Universe is quite inhomogeneous, it can only be represented by an FLRW metric, and that the process requires the making of a lot of choices w.r.t. how peculiar velocities are treated etc. https://iopscience.iop.org/article/10.1088/0264-9381/4/6/025
This is also the core of the Green and Wald vs Buchert, Ellis ..... debate. https://arxiv.org/abs/1505.07800
Incidentally Sarkar's recent paper (1808.04597) was attacked by Rubin (Saul Perlmutters former PhD student) & Heitlauf: https://arxiv.org/abs/1912.02191
And Sarkar and co seem to now be waiting for their response to get reviewed: https://arxiv.org/abs/1912.04257
The gist of it seems to be that SN1a data shows an acceleration only when about 70% of the data have been corrected towards the 'cosmic rest frame' using a model of the local peculiar velocities that already assumes concordance cosmology, and in the process inserts an arbitrary discontinuity within the data of about 0.07 magnitudes (when the evidence for acceleration in Perlmutter 1999 was stated as the high redshift supernovae were dimmer by about 0.15 mag compared to low redshift ones). Of course, general relativity is based on the idea that there are no preferred frames (inertial or non inertial).
Sarkar also seems to have found a lot of issues with the SN1a data itself:
https://arxiv.org/abs/1911.06456
and in a recent interview has described the data as 'doctored'.
http://backreaction.blogspot.com/2020/03/how-good-is-evidence-for-dark-energy.html
I think the mainstream of cosmology is George Ellis, and ignoring the 1987 'fitting problem in cosmology' to use sparse directionally skewed data to claim dark energy with bad statistical methods makes Riess, Perlmutter etc the ones who do sensationalized research.
Given these nuances and the recent crisis in cosmology, I would suggest that this article be expanded to also include the possibility that dark energy is pseudoscience. I will make an attempt myself once the above Silk and Sarkar papers are in print.
BattleOrc ( talk) 13:52, 23 April 2020 (UTC)
Hahaha. You seem to have ignored the second Silk paper which literally calls for a 'drastically different model'. In addition, you may note that:
The debate that concluded in 2015, between Robert Wald and collaborators on one side and Rocky Kolb, George Ellis etc on the other hand ( https://arxiv.org/abs/1505.07800 ) is something without parallels in other fields of science. If this happened in particle physics, it would be like Michael Peskin and Francis Halzen debating if quarks are real. And this is because you cant just use GR at 'cosmological scales' (weasel words), when its geometric effects have been verified at solar system scales, and the Field equations connect the local metric with the local stress energy tensor, which means that any dynamical model that describes the whole (clearly inhomogeneous) Universe is a coarse grained average of physics that is happening at solar system scales. There is no reason to believe that the averaged out model is FLRW. Go read some George Ellis papers. FLRW is not the same as GR. It's a toy model. You may find table 1 of https://arxiv.org/abs/2002.10831 useful. Also, https://arxiv.org/abs/1109.2314
So once the above eprints are published, I will be attempting to rewrite this article to point out that DE should be treated as pseudoscience. BattleOrc ( talk)
wimps, machos.. are proposited particles, with little experimental checking. we know little to nothing about black holes, their mass their age. and their evolution. we imaged just one. they could harbour more mass than we know. something else on our known theories can say light is wave or particle, but a theory says it is not either something 'we cant imagine'. what cant we imagine? how can we make any assumptions on anything if we can´t explain light and electromagnetism? dark matter and energy was proposed, it is magical and aesthetical. found the higgs boson at great cost. why not find the supposedly darkwhatever matter or energy which would be the most abundant? — Preceding unsigned comment added by Abestrobi ( talk • contribs) 02:06, 22 February 2021 (UTC)
From the introductory paragraph : "Prior to these observations, the only forms of matter–energy known to exist were ordinary matter, antimatter, dark matter, and radiation." I find this language problematic. Dark matter is not "known" to exist, unlike the other items mentioned. It is hypothesized or inferred to exist but has never been observed directly or discovered (a la the Higgs boson, e.g.). Indeed, when one clicks the link to dark matter, it quickly becomes clear that its existence is the currently favored hypothesis but is not settled science. Also, the language used implies that dark energy is also "known" to exist, which is false for the same reasons I listed for dark matter, and of course farther down the page competing ideas are discussed. That sentence of the introduction needs an overhaul. I'm hoping someone else will do it but will do it myself eventually if not. 2601:41:200:5260:7901:2F51:EBEF:946E ( talk) 21:42, 29 May 2021 (UTC)
Currently there's a FAQ for the question "The total amount of dark energy increases as space expands. Doesn't that violate conservation of energy?". The answer given is "Conservation of energy is not well-defined in curved spacetime, since the stress-energy tensor does not transform cleanly under change of coordinates. In the Newtonian interpretation of the FRW metric, the extra dark energy created by the expansion of space is balanced out by the decrease in gravitational energy."
Are we sure this is correct? I'm under the impression that energy is not expected to be conserved because the metric of the universe is not time-invariant (in turn because the universe is expanding). Ping LaundryPizza03. Banedon ( talk) 08:57, 16 December 2021 (UTC)
Currently (29 May 2022) the article contains two almost identical figures about the estimated distribution of matter and energy in the universe. The numbers used are not identical - the second figure use more recent numbers. I propose to consolidate both figures and use the same numbers in the article. — Preceding unsigned comment added by Steffeler ( talk • contribs) 20:09, 29 May 2022 (UTC)
I came here looking for the density of dark energy in SI units (joules per cubic metre) and could not find it. Can this be corrected please ? It seems like a simple thing to ask for and a serious omission. 84.66.21.64 ( talk) 09:51, 14 December 2022 (UTC)
Actually, I think that this entire section should be removed. Merritt claims to evaluate things objectively, but actually pushes MOND as an alternative (actually, false dichotomy) to conventional cosmology. He is neither a well respected philosopher of science and, as his writings show, as noted in the referenced article, seems to know little about cosmology. Certainly his ideas are not consensus. Does one have to prove that they are not consensus? That is like a court asking a defendant to prove their innocence. With regard to dark energy, he makes many claims which are demonstrably false, hence the added reference which has a large number of references to back up its rebuttal of Merritt. This is not the place to repeat the rebuttal; those interested can read the article (freely available). — Preceding unsigned comment added by 2001:9E8:239D:EB00:B09D:197F:F6D0:C2B1 ( talk) 08:14, 4 January 2023 (UTC)
This article was the subject of a Wiki Education Foundation-supported course assignment, between 7 September 2022 and 24 December 2022. Further details are available
on the course page. Student editor(s):
Jeffrey Sucuzhanay (
article contribs).
— Assignment last updated by Janyahmercedes ( talk) 02:52, 26 January 2023 (UTC)
Hi, just heard this news. I'm not sure how best to edit this article, but thought someone better than me could use this
Chupon ( talk) 18:49, 16 February 2023 (UTC)
The article is suitably referenced, with inline citations. It has reliable sources, and any important or controversial material which is likely to be challenged is cited.The article fails the criteria, reassess classification to C-class. It is also tagged as "needing clarification" from January 2023 which is not indicative of "well written" per criteria #4.
Links in the "External links" section should be kept to a minimum. A lack of external links or a small number of external links is not a reason to add external links.
There is nothing wrong with adding one or more useful content-relevant links to the external links section of an article; however, excessive lists can dwarf articles and detract from the purpose of Wikipedia. On articles about topics with many fansites, for example, including a link to one major fansite may be appropriate.
Minimize the number of links. I will trim all but the first three and article regulars can review them. -- Otr500 ( talk) 15:08, 28 February 2023 (UTC)
Do not use {{ cite web}} or other citation templates in the External links section. Citation templates are permitted in the Further reading section.-- Otr500 ( talk) 15:22, 28 February 2023 (UTC)
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Hello,
The first papers that collected data from supernovae which originated the idea for dark matter are this one by Riess Et al. and this other one by Perlmutter Et al., both from the late 1990s.The references could be added to the beginning of the article Mexican Physicist ( talk) 17:09, 31 August 2023 (UTC)
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The second sentence of the introduction currently reads:
> The first observational evidence for its existence came from measurements of supernovas, which showed that the universe does not expand at a constant rate; rather, the universe's expansion is accelerating.
Instead, it should say something like:
> The first observational evidence for its existence came from measurements of supernovas, which showed that despite the gravitational attraction of the universe's matter, the expansion of the universe is not slowing down; rather, the universe's expansion is accelerating.
Or more simply, since the expectation of deceleration is mentioned later in the paragraph:
> The first observational evidence for its existence came from measurements of supernovas, which showed that the universe's expansion is accelerating.
The reason for either change is that there was never any reasonable expectation ( at least since the 1930s) that the universe would expand at a constant rate. Aseyhe ( talk) 18:51, 9 September 2023 (UTC)
Currently missing from the article is any mention that dark energy suppresses the growth of structure. astro-ph/0305286 and astro-ph/0604485 are early theory papers on the idea, particularly pointing out that it can distinguish dark energy from modified gravity. There's also a recent review at 2212.05003. For example, the WiggleZ survey mentioned in the large-scale structure section used measurements of both the expansion rate and the growth rate to constrain dark energy (per their article, which may be different from the one the cited news stories are referring to, but I can't actually figure out which article the stories are referring to).
Aseyhe ( talk) 19:24, 9 September 2023 (UTC)
So, radiation Density and mass Density declines but dark energy is constant as the universe expands? 3MRB1 ( talk) 11:37, 20 December 2023 (UTC)
Why is this article only listed as high importance and not top? I feel like this is just as important as dark matter (or more in my opinion), given the huge mass-energy content and its impact on the expansion of the universe. I assume this is determined based on Content assessment and Importance of topic. Given those are the correct links I have read, I am still unsure why this subject received only a high level. Xiberion ( talk) 12:19, 7 March 2024 (UTC)