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Researcher proposes model replacing dark energy/matter to explain universe
- wglb 2y agoRelated paper: https://iopscience.iop.org/article/10.1088/1361-6382/adbed1 https://iopscience.iop.org/article/10.1088/1361-6382/adbed1
- fguerraz 2y agoI don't have access to the paper, but it seems to make zero testable predictions and is therefore just mathematical fiction. If it's not falsifiable, it's not science. EDIT: the last sentence is "Given sufficient redshift (or, equivalently, time) resolution effected by the redshift slicing, one might just find that the Hubble diagram exhibits jumps in the redshift distance relation, which would be very revealing." So they say it's testable. However, we see the effects of "dark matter" (or whatever it really is) today affecting the spin of galaxies, so I don't see how that's compatible with the explanation of these events being "rare".
- Xelbair 2y agowelcome to modern physics, enjoy your stay.
- mr_mitm 2y agoHe wants to look for discontinuities in the Hubble relation. Quoting from the article: > Looking to the future of his research, Lieu says the next step to validating his model of the cosmos could come through observations using earthbound instruments rather than something like the James Webb Space Telescope. >"The best way to look for the proposed effect is actually to use a large ground-based telescope—like the Keck Observatory [Waimea, Hawaii], or the Isaac Newton Group of Telescopes in La Palma, Spain—to perform deep field observations, the data of which would be 'sliced' according to redshift," the researcher notes. >"Given sufficient redshift (or, equivalently, time) resolution effected by the redshift slicing, one might just find that the Hubble diagram exhibits jumps in the redshift distance relation, which would be very revealing." Not sure how feasible this is though.
- ForOldHack 2y agoI would argue that it is falsifiable. What I think you are looking for is verifiable and repeatable. It took almost 30 years to verify Einstien. He said about the collection of a hundred papers trying to prove he is wrong, "you only need one paper to prove it wrong." It's a therotical paper. Leave it to the expermentaliats to design a test to prove it right. Diffraction gratings prove QED. Right. Feynman's biographer said that.
- ColinHayhurst 2y agoPaper here: https://arxiv.org/pdf/2503.08733 https://arxiv.org/pdf/2503.08733 TL;DR - replace one big singularity with multiple singularities. As in last sentence there is "The only difference between this work and the standard model is that the temporal singularity occurred only once in the latter, but more than once in the former." tldr
- andy_ppp 2y agoI’ve never really understood how just adding extra invisible stuff to make the equations work is justified either? It seems more likely there is simply something wrong with the equations.
- mr_mitm 2y agoThis is basically the first and most common objection laypeople have. (In fact, this comes up in every single thread on HN about DM, not exaggerating.) Believe it or not, scientists have thought of that as well. They tried, and nothing fits the data as well as the standard model. The trope is so common that there even is an xkcd for it: https://www.xkcd.com/1758/ https://www.xkcd.com/1758/
- JackSlateur 2y agoA common objection, and for good reason: just because you do not know the right model does not make your bad model somehow true I mean, when you miss 85% of the stuff, you gotta admit that, perhaps, your stuff is wrong And yes, it can work even if it is wrong
- mr_mitm 2y agoNobody said it's "true", whatever that even means for a model. The claim is that it's the best anyone has been able to come up with. And not for a lack of trying. Everybody also acknowledges that there are issue with DM, it's just that every other known model has bigger issues.
- JackSlateur 2y agoHa, my bad When you write "this is the [..] most common objection laypeople have", I understood "In contrast with the experts who know better" Of course, if as you say, everybody knows that this is a wrong, specifying "laypeople" seems unnecessary
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- nodfyr 2y agoAll these papers miss the fact that our main evidence for dark matter (or something like it) is the cosmic microwave background. I see no mention on how this very convoluted model can reproduce it. The evidence is in the oscillations of the primordial plasma seen directly in the CMB. These come from the gravity pulling the plasma and pressure pushing back. Without DM they would be too shallow, DM helps by pulling the plasma gravitationally without opposing the fall with pressure of its own.
- nobody9999 2y ago>All these papers miss the fact that our main evidence for dark matter (or something like it) is the cosmic microwave background. I see no mention on how this very convoluted model can reproduce it. I am not an astronomer, but IIUC (and I may not), the first evidence for dark matter was posited by Fritz Zwicky[0] in 1933 based on the rotational velocities of galaxies, work by Vera Rubin[1] confirmed Zwicky's hypothesis in more detail decades later. Since then Rubin's work has repeatedly been confirmed. And while Penzius and Wilson "discovered" the Cosmic Microwave Background (CMB) a few years before Rubin published her data, (again, IIUC) the CMB was not used as a reliable tool to look for dark matter until better quality data was gathered in the 1980s and 1990s. [0] https://en.wikipedia.org/wiki/Fritz_Zwicky#Dark_matter https://en.wikipedia.org/wiki/Fritz_Zwicky#Dark_matter [1] https://en.wikipedia.org/wiki/Vera_Rubin#Rotational_curves https://en.wikipedia.org/wiki/Vera_Rubin#Rotational_curves Edit: Clarified prose.
- andrewflnr 2y agoThey didn't say it was always the main evidence, just that it now is. I'm not personally sure about that either, but it's definitely one of the major lines of evidence.
- Tagbert 2y ago“ All these papers miss the fact that our main evidence for dark matter (or something like it) is the cosmic microwave background. ” There is also the galactic rotation curve evidence. With Newtonian physics, the visible mass in galaxies should rotate faster toward the center and slower toward the edge. This is the rotation curve. We actually observe a very linear curve, where the outer stars and gases rotate at the same speed or even faster than the centers. A dark matter halo would provide the additional gravitational mass for cohesion.
- baxtr 2y agoNot sure why you’re being downvoted. If a theory doesn’t generate at least one falsifiable prediction it’s not a scientific theory.
- T-A 2y ago> I don't have access to the paper https://arxiv.org/abs/2503.08733 https://arxiv.org/abs/2503.08733 > it seems to make zero testable predictions and is therefore just mathematical fiction I'll have a look when I get the time, but the reference to his previous paper really doesn't bode well.
- throwaway81523 2y agophys.org used to be less of a gosh wow outlet.
- fhars 2y agoReally? Since I first noticed links to pyhs.org on HN, I have always wondered why it is not permanently banned as a link target.
- uninformed-me00 2y agophys.org as a domain feels reliable, I guess that's how they make money doing "non-profit" (by having negative effects on humanity) stuff.
- scotty79 2y agoThe amount of ads I see there in Chrome is stunning.
- scotty79 2y ago> The origin of these temporal singularities is unknown—safe to say that the same is true of the moment of the Big Bang itself If you still want to assume that weird things you mathematically need happen whenever you need them for no reason then why not stick with cosmic inflation?
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- DrNosferatu 2y agoHere: https://arxiv.org/pdf/2503.08733 https://arxiv.org/pdf/2503.08733 Only managed a first read, but it seems there's no explanation for the CMB. Let alone any explanation for the CMB power spectrum peaks... ...therefore I won't bother further ;)
- DrNosferatu 2y agoIf you ask me, Inflation is far more problematic than the Dark Stuff. Nevertheless, so far it remains the best explanation we have for observed phenomena ¯\_(ツ)_/¯
- sesm 2y agoWhat does inflation explain though? It was proposed as an explanation for CMB spectrum. Anything else?
- btouellette 2y agoIt's obviously tied pretty closely to any theory of large scale structure formation too
- DrNosferatu 2y agoRapid expansion of the early Universe. We need to have Inflation in order for the Big Bang to work as a theory. Without it, the Big Bang theory runs into major problems: 1. The Horizon Problem: The cosmic microwave background (CMB) has nearly identical temperature in all directions, suggesting the entire observable universe was once in contact. But without inflation, opposite sides of our universe would never have been able to “communicate” and reach this equilibrium. 2. The Flatness Problem: Our universe is remarkably “flat” (parallel lines stay parallel), which would require impossibly precise initial conditions without inflation. 3. The Origin of Structure: Inflation explains how quantum fluctuations during this expansion became the seeds for galaxies and cosmic structures we see today.
- hwillis 2y agoDefinitely more problematic. And Webb only made it more confusing :( https://en.wikipedia.org/wiki/Cosmological_constant_problem https://en.wikipedia.org/wiki/Cosmological_constant_problem > Depending on the Planck energy cutoff and other factors, the quantum vacuum energy contribution to the effective cosmological constant is calculated to be between 50 and as many as 120 orders of magnitude greater than has actually been observed, a state of affairs described by physicists as "the largest discrepancy between theory and experiment in all of science" and "the worst theoretical prediction in the history of physics".
- dventimi 2y agoThere seems to me to be a real cottage industry in proposing alternatives to Dark Matter and Dark Energy. I wonder why that might be. Why isn't there as much interest in alternatives to, say, Plate Tectonics or the Germ Theory?
- aaomidi 2y agoBecause those are coherent theories, that don’t have massive gaps in them like dark matter.
- dventimi 2y agoWhat massive gaps?
- DFHippie 2y agoI am not a physicist, buy maybe the nature of dark matter and dark energy? What are their properties aside from their effect on the large scale structure of the universe?
- dventimi 2y agoFWIW (which is not much), I was an astrophysicist whose research was Dark Energy, though I arrogate to myself no authority on this topic as frankly a lot of knowledge I used to possess on the topic has been replaced by knowledge of tedious programming APIs (meh...it's a living). My sense was that, perhaps owning to their colorful (colorless?) names, and because they diffused into popular culture more than other equally-important theories in other fields, Dark Matter and Dark Energy were presented to and apprehended by laypeople as "exotic". This invited speculation about these theories and even an urge to overturn them, especially where "exotic" was equated with "tendentious." But, by my lights these theories aren't very exotic. Dark Matter especially seems to me to be very consistent with the history of particle physics. Rutherford first proposed the existence of the neutron in 1920, but it wasn't observed directly until 1932. Pauli first proposed the existence of the neutrino in 1930, but it wasn't observed directly until 1956. Both are forms of "dark matter" and neutrinos were once a candidate for explaining flat rotation curves in galaxies and the "missing mass problem", until they were later excluded by observations of large scale structure. Dark Matter interacts with gravity strongly enough that its effects on astronomical and cosmological scales are pronounced, but it interacts with the other forces weakly enough that so far it hasn't been observed directly. So what? "the nature of dark matter and dark energy" I don't know anything about "the nature" of things. That sounds very philosophical to me. "What are [the properties of Dark Matter and Dark Energy] aside from their effect on the large scale structure of the universe?" I don't know. I also don't know why you're excluding (in the case of Dark Matter) its gravimetric effect on the large scale structure of the Universe. That seems like a pretty important property to me.
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- andrewstuart 2y agoHelp me understand how can something so hard to detect exist in such vast quantity to change the rotation of galaxies.
- dventimi 2y agoPeople and scientific instruments are made of "normal" (non-Dark) matter, which makes it easy to detect other "normal" matter (electrons, protons, quarks, photons, neutrinos, what-have-you). It's hard for us and our instruments to detect or even be aware of Dark matter at laboratory scales, which operate over the electromagnetic and nuclear forces which Dark Matter feels little or not at all. At astronomical scales, however, things are different. At those scales, gravity wins out, and is one of the dominant things we observe in astronomy. Dark Matter may not feel the electromagnetic and nuclear forces the way normal matter does, but it feels gravity the same as every other particle does. Nobody gets a pass from gravity, not even Dark Matter. Consequently, it's relatively easy to observe the gravitational effects of Dark Matter at the astronomical scales of the rotation of galaxies and the dynamics of galaxy clusters, even while it's difficult or impossible to observe the non-gravitational effects of Dark Matter at laboratory scales.
- ldunn 2y agoWhy do you think that how hard it is to detect should have anything to do with how much of it there is?
- naasking 2y ago> Why do you think that how hard it is to detect should have anything to do with how much of it there is? Basic statistics. If you have lots of stuff, the probability of detection should be higher, all else being equal.
- ldunn 2y agoThis tells you that the chance of detecting dark matter is higher than it would be if it were only, say, 0.1% of the energy content of the Universe. Which is true, but so what? Maybe you mean that this is a sense in which how hard it is to detect has something to do with how much of it there is, which is fine, but the original question is suggesting some much more constraining relationship, where the fact that dark matter is hard to detect and the fact that there is a lot of it poses some kind of apparent contradiction, or at least a puzzle. I don't know of a reason to think that any such contradiction exists.