[HN Gopher] Supernovae Evidence for Foundational Change to Cosmo...
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Supernovae Evidence for Foundational Change to Cosmological Models
Author : jandrewrogers
Score : 85 points
Date : 2024-12-23 16:44 UTC (1 days ago)
(HTM) web link (arxiv.org)
(TXT) w3m dump (arxiv.org)
| api wrote:
| Good wikipedia article on these types of cosmologies including
| timescape cosmology:
|
| https://en.wikipedia.org/wiki/Inhomogeneous_cosmology
| numpy-thagoras wrote:
| Many advancements in science have happened because we stopped
| for a second, and then looked to generalize our assumptions.
| Consider,
|
| e.g.
|
| Euclidean geometry -> non-euclidean geometry; Classical
| analysis -> nonstandard analysis; Linearity -> non-linearity;
| Homogeneity -> inhomogeneity; Flat spacetime -> curved
| spacetime; Singular probabilities -> superposition.
|
| All of these were loosening of certain criteria that opened up
| many possibilities. It is certainly erroneous to assume we
| must, by necessity, have a homogeneous cosmology.
| molticrystal wrote:
| This paper argues that the Timescape model [0] provides a better
| fit than the cold dark matter model when examining Type Ia
| Supernovae. According to the Timescape model, clocks run faster
| in voids where the gravitational field is less, and significant
| differences exist between a galaxy floating in a void and one
| like the Milky Way Galaxy. The Timescape model suggests that
| other models, which fail to account for these differences, lead
| to less accurate calculations and less plausible solutions.
|
| [0]
| https://en.wikipedia.org/wiki/Inhomogeneous_cosmology?useski...
| vlovich123 wrote:
| If clocks run slower in the presence of gravity, wouldn't it
| stand to reason it runs more quickly in a void where there's
| less gravity? Or is the model saying that clocks run even
| faster in a void than Einstein's theory predicts?
| vecter wrote:
| Clocks run at "normal" speed (i.e. "1x" speed) in the absence
| of a gravitational field. The stronger the gravity, the
| slower they run (i.e. less than "1x" speed).
| vlovich123 wrote:
| Right so is the paper saying that lambda CM completely
| ignored clock differences due to heterogeneity in mass
| distribution in the universe where isolated galaxies would
| be experiencing less time slowing than galaxies near other
| galaxies which would experience more time dilation?
| raattgift wrote:
| In the standard cosmology the Integrated Sachs-Wolfe
| effect captures the redshift/blueshift of distant light
| sources (up to the Cosmic Microwave Background) as it
| traverses relatively dense regions and relative voids.
|
| https://en.wikipedia.org/wiki/Sachs%E2%80%93Wolfe_effect
|
| Note that in the next paragraph I depart significantly
| from the vocabulary that the Timescapes programme
| proponents have been using for the past twenty years.
|
| ISW and comparable spectroscopy is easy enough to think
| about in terms of an accelerating cosmic expansion, i.e.,
| relative voids are becoming spatially bigger with the
| expansion. It becomes much less intuitive how to fit the
| data if one keeps relative voids at roughly constant
| volume instead implying that there is a significant false
| vacuum above the ground state and in voids the false
| vacuum is _slowly_ decaying to that state. (Outside the
| supervoids, near matter, this false vacuum decays much
| more slowly still). Because "vacuum" in the voids isn't
| really vacuum, one is stuck with a running function on
| the constant c (it gets faster with time from the
| formation of the CMB; this is because the false vacuum
| evolves towards a real vacuum) or adapting lightlike
| geodesics by imposing refraction (since the false vacuum
| is a medium).
|
| The usual terminology is reasonably capture in the first
| paragraph here at <https://en.wikipedia.org/wiki/Inhomoge
| neous_cosmology#Inhomo...> ("Inhomogeneous universe").
| The following short section ("Perturbative approach") is
| what is done in the standard cosmology when one wants to
| do detailed studies of filamentary distributions and
| other structures that are lumpy at some (larrrrrge)
| length scale of interest: the perturbed homogenous
| background is practically always the standard FLRW.
|
| The justification for perturbation theory on FLRW is that
| even though there are dense spots (notably most galaxies'
| central black holes), principles like the Birkhoff
| theorem capture the idea that as you get far enough away
| from a galaxy it behaves more and more like a small
| shell, and this happens at _intragalactic_ scales for
| these SMBHs: gravitationally, even to its arms '
| structure, it makes practically no difference whether
| Andromeda's central bulge has a lot more stars/gas/dust
| or whether it has one, two, or six central SMBHs (at
| enough spatial separation that they're not mutually
| orbiting in a way that would generate gravitational
| radiation our observatories are sensitive to).
|
| The same idea applies to galaxies->galaxy
| clusters->filamentary structures: as you "zoom out" the
| density variations become less important: filaments are
| pretty sparse on average.
|
| The Timescapes programe wants a sharper difference in
| matter sparseness between voids and filaments, and
| proposes that gravitational backreaction by the matter is
| responsible for generating that: the presence of matter
| steepens the density of matter over time (without the
| visible matter clearly becoming denser). I don't
| personally see how that's much different from a false-
| vacuum decay in the voids, conceptually. (ETA: well, it
| depends somewhat on how the Timescape void fraction
| evolves, but the local universe VF doesn't run void
| clocks fast enough, unless we do violence to the
| Copernican principle.)
|
| (Also ETA, mostly a note-to-self: I also don't understand
| how they capture the angular diameter turnover point in
| their dressed geometry <https://journals.aps.org/prd/abst
| ract/10.1103/PhysRevD.80.12...> PDF available from
| institution at <https://ir.canterbury.ac.nz/items/36fe829
| a-0e7a-45d6-8db6-c2...> (cf <https://astronomy.stackexcha
| nge.com/questions/21006/understa...>.))
|
| Finally, I think the most important result of this latest
| Timescapes paper is a reminder to everyone that supernova
| data are a mess. A good X-mas present would be a couple
| readily visible Milky Way supernovae.
|
| -
| brotchie wrote:
| Pet theory is that our universe is run on some external
| computational substrate. A lot of the strangeness we see in
| quantum physics are side effects of how that computation is
| executed efficiently.
|
| The inability to reconcile quantum field theory and general
| relativity is the that gravity is a fundamentally different
| thing to matter: matter is an information system that's run to
| execute the laws of physics, gravity is a side effect of the
| underlying architecture being parallelized across many compute
| nodes.
|
| The speed of light limitation is the side-effect of it taking a
| finite time for information to propagate in the underlying
| computational substrate.
|
| The top-level calculation the universe is running is constantly
| trying to balance computation efficiently among the compute
| nodes in the substrate: e.g. the universe is trying to maintain
| a constant complexity density across all compute nodes.
|
| Black holes act as complexity sinks, effectively "garbage
| collection." The matter than falls below the event horizon is
| effectively removed from the computation needs of the
| substrate. The cosmological constant can be explained by more
| compute power being available as more and more matter is
| consumed by black holes.
|
| This can be introduced into GR by adding a new scalar field
| whose distribution encodes "complexity density." e.g. some
| metric of complexity like counting micro-states, etc. This
| scalar field attempts to remain spatially uniform in order to
| best "smooth" computation across the computational substrate.
| If you apply this to a galaxy with a large central supermassive
| black hole, you end up with almost a point sink of complexity
| at the center, then a large area of high complexity in the
| accretion disk, and then a gradient of complexity away towards
| the edges of the galaxy. That is, the scalar field has strong
| gradients along the radius of the galaxy, and this gives rise
| to varying gravitational effects over the radius (very MOND-
| like).
|
| Some back of the napkin calculations show that adding this
| complexity density scalar field to GR does replicate observed
| rotation curves of galaxies. Would love to formalize this and
| run some numerical simulations.
|
| Would hope that fitting the free parameters of GR with this
| complexity density scalar field would yield some testable
| predictions that differ from current naive assumptions around
| dark matter and dark energy.
| cma wrote:
| There's a Danny Hillis talk on this but I couldn't find it.
| fsloth wrote:
| "External computation susbtrate" is a useful idea if it leads
| to falsifiable theories. As a "theory of everything" it sucks
| because it's clearly not motivated by any specific maths or
| observations, but by the human need to map nature into some
| comprehensible analogue. Ie. taking some simpler subset of
| nature and trying to pretend the rest of it is like that as
| well. Usually nature so far has become more incomprehensible
| the deeper we've looked at it.
|
| Newtonian mechanics & mechanical clocks being hottest
| precision technique led scientists at the time to viewing
| nature as a clockwork. Now we have computers, we think
| "nature is like computers" because it's an appealing
| analogue.
|
| But it's a false analogue imo. Just like clocks are a thing
| enabled by nature (a subset, in every meaning of the word)
| similarly computers are a subset of nature. So yes, nature
| can think (with human brains) and nature can run computations
| (with cpu:s impregnated with programs) but that also is just
| a subset of nature.
|
| Now: games of the mind and helpfull analogues rock. And
| asking "how is nature analogous to a turing machine" is
| interesting for sure. But just because a game is fun or
| analogue appealing, should not one let forget in the
| philosophical sense that one is playing only with a limited
| subset of a thing.
| T-A wrote:
| > a better fit than the cold dark matter model
|
| than the _Lambda_ Cold Dark Matter model.
|
| Lambda, i.e. the cosmological constant, a.k.a. dark energy, is
| what they do away with, not dark matter.
| SpaceManNabs wrote:
| Thanks for saving me time in dismissing this paper lol. Any
| time somebody wants to get rid of dark energy, i run into
| some garbage. Reminds me of the mond nuts
|
| Just reading the rest of the comment section is enough to
| help me verify that.
|
| For some reason, hackernews always gets kooky when it comes
| to this stuff.
| webdoodle wrote:
| Can't censor it, so you gaslight it?
| andrewflnr wrote:
| I don't know, the evidence for dark energy has always
| seemed a lot sketchier than the evidence for dark matter.
| Dark matter has lots of interlocking lines of evidence.
| Isn't dark energy pretty much entirely based on various
| cosmic distance measures that all have huge stacks of
| assumptions embedded?
| SpaceManNabs wrote:
| I agree. Until i see better evidence for 1a, wmap, and
| cluster formation in another theory, i really want all
| the charlatans to be quiet. We dont know what dark energy
| is, but we have decent evidence to say it is there and
| also decent theory.
|
| I am not saying this paper is made by charlatan btw. This
| type of work attracts those people though.
| ajross wrote:
| Webb is turning out to be one of the most impactful pieces of
| scientific apparatus of the last century or so. Not that it took
| all the relevant data, but that it was the final thing that broke
| open all the doors being held shut. We're watching a Kuhnian
| paradigm shift in astronomy unfold in real time.
| epicureanideal wrote:
| I'll be happy to see all the dark matter, dark energy stuff
| explained away.
| SpaceManNabs wrote:
| We have a century's worth of evidence for dark matter and
| about 20 years worth of evidence for dark energy.
|
| Once an alternative theory stands up to scrutiny, maybe we
| shouldnt a priori dismiss things we dont understand?
| PaulHoule wrote:
| There's been a general problem in astronomy for a long time that
| it seems like there just hasn't been enough time for objects to
| develop
|
| The oldest version of this I know of can be seen in a diagram of
| ways that large black holes could possibly form in this book
|
| https://en.wikipedia.org/wiki/Gravitation_(book)
|
| which shows as early in 1973 people knew they had no idea how
| supermassive black holes could possibly form. Lately these
| problems have intensified because Webb seems to see that all
| sorts of developments seemed to happen a lot more quickly than
| they should of which leaves one wondering if the first billion
| years were really the first ten billion years. Could Timescape
| explain that?
| api wrote:
| AFAIK one possible explanation for the black hole issues could
| be primordial black holes, which are also a candidate for at
| least a component of dark matter.
| PaulHoule wrote:
| Yep. There is the idea that you could get little primordial
| black holes (that maybe weigh as much as a mountain and could
| be evaporating now) and the idea that you could get huge
| primordial black holes. Also the occasional strange idea that
| the universe might be cyclic (not too fashionable but can
| fill the hole left by inflation) and that black holes can
| survive the crunch.
| numpy-thagoras wrote:
| Black holes can survive a Big Crunch scenario? That can go
| a long way to explaining many things. Can you please
| provide a paper with more references to this, and
| potentially one with an example mechanism?
| api wrote:
| I love the idea. It's one of our current physics hypotheses
| I hope is true, because it means the universe would be full
| of tiny things the size of a hydrogen atom with the mass of
| asteroids.
|
| "The devil's glitter?"
|
| BTW they would not suck up planets and stuff like
| inaccurate sci-fi. One could be going real fast and fire
| right though the Earth and do little, maybe cause some
| seismic events, but we would never know unless we knew
| exactly what to look for. A tiny black hole would have a
| tiny event horizon.
|
| If you dropped one into a planet or star with a low enough
| velocity that it didn't shoot out the other side it might
| do a lot of damage, then come to rest in the middle and
| slowly grow. I recall reading that one in Earth's core
| would take possibly millions of years to do much since the
| radiation pressure caused by accretion around it would
| limit the rate of matter falling into it. Earth would
| eventually become an Earth mass black hole but it would not
| happen in any human lifetime, possibly not in the lifetime
| of the human race.
| mutagen wrote:
| So Vernor Vinge was on to something[0] with his 'Zones of
| Thought'...
|
| [0] https://en.wikipedia.org/wiki/A_Fire_Upon_the_Deep#Setting
| shepardrtc wrote:
| Well his idea was that the laws of physics actually change
| depending on the distance from the galactic center. Far enough
| out, information can be transferred faster than the speed of
| light. Too close and life stops working. Which honestly seems
| much more fun than gravity slowing things down a bit.
| scrubs wrote:
| I'm surprised cosmology hasn't accounted for differences in
| clocks given how central GR is to astronomy. Granted I am no
| expert, but adding this dynamic was, until today, a bridge too
| far, or thought to average out somehow and not be pertinent
| itishappy wrote:
| Huh?
|
| https://en.wikipedia.org/wiki/Cosmic_time
| codethief wrote:
| > cosmology hasn't accounted for differences in clocks given
| how central GR is to astronomy
|
| Of course it has. Yes, LCDM's FLRW metric, by its defining
| assumption of spatial homogeneity, doesn't allow the metric
| (let alone the speed of clocks) to vary spatially. However, it
| is very common to do perturbation theory on top of the FLRW
| metric to account for density fluctuations. Besides, there are
| also models like LTB (Lemaitre-Tolman-Bondi) which give up on
| homogeneity at the non-perturbative level (while still
| preserving isotropy, though).
|
| All in all, the idea that local voids could explain away the
| Lambda in LCDM is anything but new. It's just that the OP's
| timescape approach is the first one that seems to produce
| promising results. (Disclaimer: I merely skimmed the paper.)
| scrubs wrote:
| Point taken. Thanks.
| eximius wrote:
| Is anyone familiar with the (ln B > x) notation being used? What
| is this value being referenced?
| the8472 wrote:
| See section 2 of the paper.
| tigerlily wrote:
| This is the opening salvo in cosmology's Battle of Trafalgar.
| Dave Wiltshire has lined up a set piece 20 years in the making
| that is going to obliterate both lambda CDM and MOND and all the
| rest.
| dcsommer wrote:
| Sounds fascinating. Anywhere I can read more about the build-up
| to this moment? Has David Wiltshire written about this?
| tigerlily wrote:
| He's been quietly publishing over the years, and waiting for
| instruments like Webb and Euclid to return data. Here's an up
| to date list:
|
| https://inspirehep.net/literature?sort=mostrecent&size=25&pa.
| ...
|
| Another list on his homepage, but not up to date:
|
| http://www2.phys.canterbury.ac.nz/~dlw24/dlw-pub.html
|
| I think the most exciting thing is probably the team he's got
| together now, and some of the computational stuff his
| associates have going at the moment.
| jandrewrogers wrote:
| An implication is that you would expect ancient advanced
| civilizations to form in the voids.
| largbae wrote:
| Wouldn't such a civilization slow down as it gathers?
| haxiomic wrote:
| A very compelling argument that the need for dark matter may be
| an artifact of a in incorrect assumption about the universe; the
| extent to which it is homogeneous and large scale structures can
| be ignored in calculations
|
| Dr Ridden, an author of this paper, has a great explainer video:
| https://www.youtube.com/watch?v=YhlPDvAdSMw
| haxiomic wrote:
| Typo: Dark Energy*, not Dark Matter
| idw wrote:
| "Cosmological models are built on a simple, century-old idea -
| but new observations demand a radical rethink" (2023) < by David
| Wiltshire, one of the authors of this paper, aimed at non-
| physicists
|
| https://theconversation.com/cosmological-models-are-built-on...
| astro-cosmo-q wrote:
| As someone who works decently close to, but not in, this area, I
| am surprised to see this on the front page of HN. The paper
| authors do not use correct statistical practices (e.g. H_0 cannot
| be fixed "as a nuisance parameter" to remove a degeneracy with
| another parameter - nuisance parameters must be marginalized
| over!) and the authors fail to account for several effects in
| their model (e.g. stretch/color factors for each supernova must
| be varied) which are _known_ to be necessary for robust inference
| of cosmological parameters from supernovae data.
|
| This is an honest question since I have seen this phenomenon
| occur a few times now with cosmology/astrophysics papers on HN:
| How did the original poster find this? And why has it gotten such
| interest/points? I sincerely hope it is simply a well-intentioned
| interest in our universe (which it greatly heartens me to see!)
| combined with naivete (not meant pejoratively, just to refer to
| lacking context) wrt the technical nature of this work, but I am
| interested to hear your thoughts.
| throwaway81523 wrote:
| It has been circulating on the intertubes. I saw it on a more
| general interest site earlier today, before seeing it on HN
| just now.
| light_hue_1 wrote:
| Funny. This is exactly how I feel about most of the AI/ML
| papers posted here. Very strange selection of pretty sketchy
| papers.
| codethief wrote:
| https://en.m.wikipedia.org/wiki/Michael_Crichton#Gell-
| Mann_a...
| andrewflnr wrote:
| > well-intentioned interest in our universe
|
| I mean, probably. Though HN does have a taste for fringe
| theories, which might color your interpretation of "well-
| intentioned". And most of us aren't really qualified to assess
| the statistical rigor of astrophysics papers, myself certainly
| included.
| necubi wrote:
| I saw it floating around Twitter with some expansive commentary
| "This could be an incredible revolution in Cosmology. The Dark
| Energy model of the universe, which won a Nobel Prize in 2011,
| may be completely wrong.", etc.
|
| For whatever reason, engineers really hate dark energy and will
| glom onto any fringe theory that appears to disprove it. Not to
| psychoanalyze too much, but it seems to be a topic where non-
| experts get to feel like they're smarter than those PhD
| cosmologists because they watched a Sabine Hossenfelder video.
|
| See literally any thread about dark energy (or dark matter,
| which elicits similar reactions) on HN.
| marcosdumay wrote:
| That is probably the same phenomenon that makes the most
| sketchy papers on nutrition science to appear on popular news.
|
| Sketchy things have the most interesting results. People that
| want entertaining news select for interesting results, and the
| sketchy ones get over-represented.
| mmooss wrote:
| > why has it gotten such interest/points?
|
| For context: The top comment on most HN stories, especially
| research, tries to completely discredit the OP, often by
| finding flaws, and especially in statistical methods.
|
| Everything has flaws. I think people are interested in what is
| valuable and possible. Shakespeare's work has many flaws, but
| that's not what people focus on.
|
| Also, while you aren't responsible for all those other top
| comments, why should I believe yours? Usually I just ignore
| these comments (but I appreciate your curiosity).
| JoeAltmaier wrote:
| Failures in statistical methods are not covered by
| 'everything has flaws'. Those are fatal, existential flaws.
| Something that is not likely true (though it is erroneously
| presented as likely of being true) are likely false.
| mmooss wrote:
| Working backwards ...
|
| > Something that is not likely true (though it is
| erroneously presented as likely of being true) are likely
| false.
|
| That doesn't make sense to me. Because something isn't
| proven here, that doesn't make it more likely to be false;
| it's just uncertain. Poor evidence is not evidence either
| way. To say it's false, it would need to be proven false,
| with good evidence. If I assert, 'the universe is expanding
| because Pluto is further away today than yesterday', my
| argument wouldn't support the claim but that doesn't
| logically imply that the universe is not expanding.
|
| > Failures in statistical methods are not covered by
| 'everything has flaws'. Those are fatal, existential flaws.
|
| Why are errors in statistical methods -- if they exist
| here: we have a hot take by a random, anonymous Internet
| commenter (using a new account) against scientists who
| spent a long time on this work, and put their names and
| reputations on it -- somehow more fatal than other errors?
|
| For example, some statistical errors lead to weaker
| results, but results nonetheless. Some lead to results with
| a somewhat different meaning. (Some lead to stronger
| results.)
|
| We need to deal with imperfect information all the time and
| find value in it, or we would have almost no information. I
| spent last week solving a problem with several routers
| interacting; I had some clear data, some unreliable
| information, and some black-hole uncertainty; I had to work
| with what I had and solve the problem. The idea that
| science is exempt from that is a fantasy of non-scientists,
| of the religion of science.
| SpaceManNabs wrote:
| I have mentioned this in two comments but HN gets really kooky
| when it comes to cosmology. A few years ago i saw a barrage of
| highly upvoted papers on MOND and de Broglie stuff.
|
| It really made me wonder what else gets posted here that is
| patently absurd but i dont have the prerequisite knowledge to
| filter it.
| codethief wrote:
| I can't speak to the technical nature of the work, as I don't
| work in the field, but the last-named author, likely the
| advisor, seems to be a respectable researcher.
|
| > I have served on the committee of the International Society
| on General Relativity and Gravitation 2017-2022, and am a past
| President of the Australasian Society for General Relativity
| and Gravitation and a past President of the New Zealand
| Institute of Physics. I served 8 years on the editorial board
| of Classical and Quantum Gravity, 2012-2019.
|
| http://www2.phys.canterbury.ac.nz/~dlw24/
|
| So while your criticism may well be justified, you make it
| sound like this is a fringe paper, which I don't think is the
| case. So instead of opening a meta discussion about what
| physics papers get posted & upvoted on HN and why (which is
| hardly novel), I'd be much more interested in how big the
| issues you're mentioning are and whether the results of the
| paper could be salvageable. I at least do think that
| Wiltshire's research is interesting and he has made good
| points[0] about the challenges of coarse-graining spacetime
| structures and where & why the underlying assumptions of LCDM
| might fail to hold.
|
| [0]: See e.g. the lecture notes on
| https://arxiv.org/abs/1311.3787
| astro-cosmo-q wrote:
| I am certainly not suggesting anything negative about the
| character or reputation of the authors of the work. I think
| that work on alternatives to the accepted concordance
| cosmology model (LCDM) should definitely be explored, and
| David Wiltshire et al. should pursue this if they deem it
| promising.
|
| As an aside: You may not find this compelling, which is
| understandable, but I will note that the vast majority of
| cosmologists (very conservatively 95%) do not question the
| FLRW aspect of the cosmological concordance model (which is
| what the paper here does away with in the alternative
| timescape cosmology), even if they question other parts of it
| (i.e. by considering dynamical dark energy, neutrino
| interactions, etc.). I agree that timescape is an interesting
| idea, but it seems like only a few people have been working
| on it for over a decade now - unless you have a very (and I
| think unfairly) dim view of professional cosmologists, if
| there was a strong case to be made for the timescape model
| based in data, the greater community would have adopted it by
| now.
|
| Finally, and independent of the sociological points above, an
| answer to your question about specifics aside from the types
| of statistical/modeling issues of the type I mentioned above.
| Again this is not exactly my area and I have not done the
| analysis myself, so I will refrain from strong opinions.
| However, my immediate reaction to this is that it is easy to
| fit one particular dataset (in this case _part_ of the
| Pantheon+ supernovae sample) with a more complicated model
| than LCDM, but often these types of models fail when other
| cosmological datasets are included. Considering such joint
| constraints with multiple datasets is not an "extra ask" of
| alternatives to LCDM - to be taken seriously any alternative
| model should hold up in a joint analysis of precision
| cosmological datasets (see, for example, the tests of a more
| seriously considered alternative model in the community,
| early dark energy [0]). These days, this is often the
| combination of Cosmic Microwave Background (CMB)
| Anisotropies, galaxy Baryon Acoustic Oscillations (BAO), and
| one of several supernovae samples - see e.g. [1] for a
| somewhat pedagogical overview. The failure to fit several
| datasets is a common issue e.g. with many MOND papers. In
| this case, the authors do not try to fit data to anything but
| a single (modified) supernovae dataset. I would expect that
| if they included a fit to CMB /BAO data, there would be
| trouble with the timescape model, as this is exactly what was
| found in an analysis of the timescape model in another state-
| of-the-art supernova dataset [2] - there the timescape model
| could not accommodate the supernova data when combined with
| CMB/BAO data [2].
|
| [0] https://arxiv.org/abs/2302.09032 [1]
| https://arxiv.org/pdf/2007.08991 [2]
| https://arxiv.org/pdf/2406.05048
| codethief wrote:
| Thanks for elaborating!
|
| > However, my immediate reaction to this is that it is easy
| to fit one particular dataset (in this case part of the
| Pantheon+ supernovae sample) with a more complicated model
| than LCDM, but often these types of models fail when other
| cosmological datasets are included.
|
| This is what I was afraid of. Thanks for the links, in
| particular for [2]!
| shepardrtc wrote:
| If this is the case then the paper is easily dismissed,
| correct? How is it being published if the flaws are immediate,
| obvious, and completely destructive to the idea being
| presented? I'm legitimately asking - I've published papers and
| reviewed them, and if I thought something was so thoroughly
| wrong, I certainly wouldn't give it the ok.
| astro-cosmo-q wrote:
| A parenthetical remark just to clarify since I was reading
| quickly. Wrt the second point in parentheses about stretch
| factors - upon a second look it is not clear to me exactly what
| is happening since they say the factors are both fixed for each
| supernova but then also list the (global?) stretch and color
| factors in Table 1 (implying that they are varied).
| throwaway290 wrote:
| Why is it a "change"? We already have two cosmology models. This
| just gives one of them more support right?
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