It's simply unnecessary to pretend its a theory, it is possible to name things without pretending they are theories.
Who did? Dark matter and energy are famously-unsolved problems in physics.
And no, I am not referring to the various MOND theories. They still belong on the same edge of that overton window that it currently occupies.
Overton windows pertain to mainstream opinions [1]. Particle physics shouldn’t be subject to mainstream opinion.
They’re calling out a “the pretense of a theory” of dark matter that we “pretended we resolved” unlike the “different but similarly unexplained phenomena were called in the past.” Where do you see the figurative gap?
In reality, we have General Relativity and the Standard Model. Both theories which have defied falsification to the limits of our instruments. Their unification, unfortunately, demands certain discrepancies be resolved. Dark matter and dark energy being possible solutions to those discrepancies. There is no “theory” of dark matter or dark energy, just a compendium of hypotheses.
OP is wrong. Literally, not figuratively.
One clearly indicates scientists being baffled (a catastrophic conclusion), versus a linguistically tangible substance "dark energy", unnecessarily specific in quantity (energy vs position vs momentum vs ...).
For unexplained phenomena, doesn't it sound alarmingly specific?
Wouldn't specific issues getting their own names not have been more desirable? like "anomalous rotation curves", ...
New observations point to possibility that dark energy might not be fixed in time nor isotropic in space. It strongly reeks of epicycles.
There is an existence of something. Unknown variables aren’t improperly named. The solution to dark energy may be matter, it may be modified gravity (almost certainly not), it might be time bubbles à la timescape (which requires re-figuring the Big Bang, possibly less parsimonious than lambda CDM).
There are terribly-named conventions in science. Dark matter is only one to the degree of explaining confident popular ignorance.
A lot of things might clear up once you remove the assumption that Big Bang was true begining of matter, energy and time, with everything isotropic instead of just temporary state of high temperature (kinetic energy) and density with its own internal structure.
Sure, but now you’ve created a magic variable the literal size of the universe. Why do we have the timescape that we do?
We have the timescape that we have because of what the distribution of mass and kinetic energy is. And why the matter is distributed like that is because it never used to be isotropic, just dense and hot. Asking why this specific distribution is what we got is like a grain of sand thrown up by exploding landmine asking why it observes this specific distribution around itself. By the way it would observe a Hubble law because faster moving grains (relatively) would move farther away during the time that passed since the blast. The correct answer to question about why it's this specific distribution definitely isn't assuming that before the blast there was no space, time or matter even though that could be the simplest mathematical thing to model.
There’s about a dozen quantum fields corresponding to particles. These form a graph, which is by no means fully connected; the fields each interact with a subset of each other, and neutrinos in particular only interact with gravity and the weak force.
If the connections are in some sense random, then it should come as no surprise whatsoever that the graph has disconnected subsets. In fact dark matter theory is effectively stating that the subset we’re a part of is one of many, which also agrees with the copernican principle.
It just means that it's plausible, and wouldn't be surprising, if there were such a field.
We already see something like this with the neutrino: they only interact via the weak force and gravity, so we need massive detectors measured in kilometres and buried underground to detect them.[1,2]
It's estimated that about 100 trillion neutrinos pass through your body every second, traveling close to the speed of light.
Now imagine a particle that doesn't even interact via the weak force. The only way we would be able to detect it is via gravity, but gravity is an extremely weak force at the individual particle level. That's a possible candidate for dark matter. (Even particles that interact only via the weak force and gravity are candidates, but it's generally believed they'd have to be more massive than neutrinos.)
There's also the possibility that, if it turns out that gravity is an emergent property arising from quantum interactions or something along those lines, that there could be fields that don't participate in the gravitational interaction. But that's highly speculative territory.
[1] Ice Cube neutrino detector: https://icecube.wisc.edu/science/icecube/
[2] Super Kamiokande neutrino detector: https://www-sk.icrr.u-tokyo.ac.jp/en/sk/
I think even calling it a particle is presupposing things we don't observe. All we know is that there are places where spacetime curves in ways our theories didn’t predict from the matter we observe.
This could be due to a particle of a field that only interacts via gravity… or it could be that there are things other than particles that bend space-time. (Like maybe there’s an entirely separate dimension of space we can’t see, but its gravity affects ours…) Or it could be that spacetime warpage propagates in different ways than we thought (“gravity is different at large distances” etc), or it could be something else entirely we haven’t even thought of.
Quantum mechanics gives us a mental framework (fields and their corresponding particles) which has been extraordinarily useful for understanding the visible universe so far, but I think it’s important to remember that it’s just a model. It isn’t reality itself.
Right, that's why I said it's a possible candidate for dark matter.
Your philosophical point about quantum field theory isn't really relevant here. The point is that, as the original commenter pointed out, we observe evidence of the presence of a set of quantum fields that act and interact in very well-defined ways. Given the nature of those interactions in the fields we can observe, it shouldn't be surprising if there are also other fields we can't observe - all it takes is a different set of coupling parameters. And we already see examples of this - we're virtually blind to interactions besides electromagnetism and gravity, and have to build enormous multi-billion dollar machines to explore other such interactions.
No-one is saying that this must be the explanation for dark matter, or that there must be other invisible fields. It's simply a natural prediction that arises from a successful theory.
I’m absolutely a layman here, so apologies if any of this is misguided or flat out wrong… but its something that’s always gnawed at me about the constant tendency to “quantize” everything including gravity and dark matter… I’ll try my best to articulate:
Fields and particles are a mathematical construct we use to describe our observations. Quantum field theory seems to be a consistent mathematical framework you can use for particle interaction once you’ve observed the properties of the particles and how strongly force is carried, etc. But each field has to have its parameters set via observation; we don’t have a good reason why particle strengths are what they are (the fine structure constant doesn’t have an understood “cause”, for example.)
But my problem with this is that it can be so general that you can postulate a new field every time you don’t understand why something works a certain way. Like, we have the em field with photons, the weak field with neutrinos, the strong field with gluons… so dark matter? Must be another field with some new particle. Gravity? Must be another field with its own graviton or something…
It’s like string theory’s 10 dimensions… I certainly don’t have the expertise to understand string theory or why the extra dimensions are required, but something rubs me the wrong way if you can just postulate another dimension every time the theory is having trouble describing reality.
I’m not saying there aren’t multiple fields or that QFT is wrong, but I will say that QFT is a model we have that usefully describes parts of reality, and we shouldn’t confuse the model with reality itself. Some subset of the phenomena we observe can be described and predicted by it, but there are many phenomena that are not predicted by it (gravity is the big one.) I’m not convinced that the fix is to just narrow down the parameters of a graviton, but instead to accept that we simply don’t know if QFT and the standard model can ever be a truly unified theory of everything or if it’s just a useful tool for a few categories of phenomena. It’s possible that we simply don’t have (and might never have) a better theory.
So when we have a problem like dark matter, to say “maybe it’s a particle in its own field” can feel a bit like physicists going back to the same old well again.
All that a field is in physics is a physical quantity that has a value at every point in spacetime.
So if we observe an electron, and we believe that electrons can appear anywhere in spacetime, then we define a field with the relevant properties, as an abstraction that allows us to model electron activity in spacetime. Aside from the mathematical details of the representation, that's all there is to it.
(Clarification: "anywhere in spacetime" can actually be a subset of spacetime, e.g. many particles could not have appeared in the early universe before the electroweak phase transition. We say the universe then had a different vacuum structure, which is equivalent to saying it had a different set of fields.)
This seems to me to negate your objection about "so general that...", at least for particles we observe. We define the fields to match the observed properties, and that's our model of that type of particle.
The second issue I see with what you're saying seems to be a kind of conflation of established theories supported by evidence, with theoretical developments in progress. Many scientists would agree that gravitons may not be the right approach - particularly those working on alternate theories, such as emergent gravity, AdS/CFT correspondence, loop quantum gravity, string theory, etc. (The full list is much longer!)
Those people working on the theories of quantum gravity are of course going to talk about gravitons, but they can't claim we know gravitons exist because we can't observe them and there isn't even a complete and consistent theory that describes them. That's still being worked on. But it's certainly an obvious avenue of research.
The same thing goes for what you said about the "constant tendency to quantize everything". For quantum objects we observe, we observe that they're quantum so there shouldn't be any controversy there. For possible objects we haven't yet observed, like dark matter or gravitons, exploring the possibility that they're quantum just makes sense, if the behavior of what we're looking for is consistent with that. It doesn't prevent research on other possibilities.
> So when we have a problem like dark matter, to say “maybe it’s a particle in its own field” can feel a bit like physicists going back to the same old well again.
If we're looking for missing mass, there's already a whole theory of how mass works, which is QFT. The theory predicts that anything with mass must be a quantum particle. Of course the theory could be incomplete, but it wouldn't make sense not to explore the possibility that other massive particles could explain our observations.
Besides, everything in the physical universe we've ever observed fits under either QFT or GR. As far as we know, that's how the universe works. It's natural to explore new phenomena from that perspective.
> (the fine structure constant doesn’t have an understood “cause”, for example.)
Funnily enough what was being discussed in this subthread can completely explain this. Imagine a very large, if not infinite number of quantum fields, each coupled to others in all sorts of possible ways. In that case, the fine structure constant we observe can be explained by the weak anthropic principle: somewhere in that large possibility space, there are likely to be fields with properties that can support the existence of observers like us.
The idea of "hidden" quantum fields is known as hidden sectors: https://en.wikipedia.org/wiki/Hidden_sector . According to the Copernican principle, we should take it seriously. There's no real reason to think that the particular set of quantum fields we're able to interact with are the only ones, just as it turned out we didn't live on the only planet, or in the only solar system, or in the only galaxy. (Although, the nature of gravity's interaction with quantum objects could constrain the possibilities here.)
I think we can say more than that. For observations to be compatible with the hypothesis that dark matter is particles or fields that interact gravitationally but not electromagnetically or strongly enough with itself to cause too much friction with itself,
It doesn’t just need to be the case that “if there was such matter at these locations at this time, then the gravitational effects on what we do see would be like what we see”. There is an additional major constraint: the dynamics of the dark matter particles/field(s) have to work with the distribution we see.
Like, if we have two regions which each have some normal matter and some dark matter, and they ran into one another, the dark matter shouldn’t be slowed by the friction in the way the visible matter is,
Etc. etc.
Like, in order for the observations to be compatible with the hypothesis that dark matter particles are the thing, the distribution of “where the dark matter would have to be in order to explain the gravitational effects” would have to be a distribution that would make sense for it to be in, under the assumption that it is dark matter particles.
There's no particular reason to expect them to collect there, except possibly a small subset of particles that has a low enough velocity to actually be gravitationally captured. But that's unlikely if they're coming from some distance from the Lagrange point. The expected quantity of particles that could be captured like this is too low to be measurable.
Keep in mind that much of the nature of what we observe in the solar system is a consequence of friction or collisions having occurred in the past: the flattened disk shape, with all the planets orbiting on a plane, the accumulation of matter into objects like stars, planets, asteroids, and comets, and the parameters of their orbits were all heavily influenced by friction and collisions. Particulate dark matter would experience none of that, so doesn't end up being as organized as ordinary matter.
For instance, in each of the 3 "generations" of quarks and leptons, separately for particles and for antiparticles, all the different kinds of charges and spin sum to zero, e.g. for the 8 particles that are the 3 kinds of u quarks + the 3 kinds of d quarks + the electron + the electronic neutrino. Moreover, in a 3-dimensional space of the "color" charges and electric charge, the 8 particles and 8 antiparticles of a "generation" are located in all the corners of 2 cubes, not in arbitrary positions.
So the set of elementary particles that we know is complete, there are no random locations where there could be extra particles.
Any so-called "dark matter", if it would exist, would have to be something completely different and not related in any way with the known elementary particles.
See recent work by Neil Turok. This podcast is one of the best popular accounts of his work:
The (Simple) Theory That Explains Everything
Why? Historically there have been two "dark matter" theories prior to this one (we speculated non-visible mass in a place to explain motion of celestial bodies). One turned out to be neptune. The other was vulcan, which turned out to be general relativity.
So historically, the inclination to invoke some form of "dark" matter is batting 50/50. im not sure i would put 50/50 into "obvious" territory
One could also argue that detections of planets from spectroscopic observations of stars is another example. The first observations of transiting exoplanets -- where the planet blocks some of the light of the star -- were actually cases where the existence of the planet had been previously inferred from Doppler shifting of the parent star (e.g., https://en.wikipedia.org/wiki/HD_209458_b).
As another example, the first evidence for dark matter came from observations in the 1930s of the Doppler shifts of galaxies in galaxy clusters, which suggested much more mass in the clusters than could be explained by the masses of the individual galaxies. Some of this "missing mass" was actually observed in the 1960s and 1970s, when orbiting X-ray telescopes showed X-ray emission from very hot, dilute gas within the clusters (unobservable from the ground because the Earth's atmosphere blocks X-rays). It turns out that the hot, X-ray-emitting gas has about five times the mass of the (stars in) the individual galaxies. So some of the missing mass has been found -- though you still need significant, as-yet-undetected extra mass in clusters to explain why they haven't flown apart long ago.
but obviously, this is a concept from general relativity which is currently not compatible with quantum field theory at all. for the purposes of QFT every particle exists within some magical separate space where all those considerations are ignored because nobody really knows how to incorporate them without breaking predictions.
One question I’ve had for a while but didn’t seem worth the look is if there any consideration for local gravitational interaction between stars exchanging momentum between them and thus flattening the rotation curve.
I’m assuming that’s one of the first things looked at but couldn’t find a paper on the subject. Remember any references on the topic?
Note that most "rotation curves" are actually measured from gas, not stars, and also that strong gravitational interactions between individual stars are extremely rare except in very dense star clusters and galactic nuclei, due to the increasingly large distances between stars as you go out from galactic centers. The time required for individual stellar interactions in the main or outer parts of galaxies to significantly affect their motions is much larger than the age of the universe (see, e.g., https://en.wikipedia.org/wiki/Stellar_dynamics).
Finally, this wouldn't address other evidence for dark matter, like the halos of hot (millions or tens of millions of K) intergalactic gas in galaxy clusters. The pressure of the gas should have driven the gas to expand way billions of years ago, if you assume that only the gravity of the individual galaxies and the gas itself is restraining it.
> strong gravitational interactions between individual stars are extremely rare except in very dense star clusters
We’re talking 225 million years for the sun to orbit the galaxy, rare events become commonplace on those timescales. Anyway, I’m sure someone has actually done this kind of simulation I’m just curious about what the result is and how they did it.
The mean time for the orbit of a star to be significantly randomized by weak, intermediate-distance interactions (e.g., the kind the Sun is experiencing now from neighboring stars) is the relaxation time, and for a star like the Sun it's of order several trillion years.
The mean time between strong gravitational interactions, where the gravity of a single nearby star significantly changes the orbit of a star (perhaps more like what you were imagining), is of order one quadrillion (10^15) years.
(Note that the numbers are for the density of the stars at the Sun's orbit; further out, where you start to get to the point where dark-matter effects really show up, the density is lower, and so these times would be even longer.)
Those are examples of "extremely rare" even on timescales of the age of the universe.
- keplerian rotation curves ("no dark matter") in elliptical and lenticular galaxies
- EFE (a group tried to find evidence against EFE and found it instead)
- early galaxies in the universe
- renzo's rule
- keplerian descent in the milky way (due to the effects of the magellanic clouds)
There's also explaining the tully-fisher relation, which is a post-hoc rationalization, so not really a prediction, but the model wasn't fine tuned to obtain the exact numerical solution.
thats a common misunderstanding of MOND and means you did not stop to understand the definition. look at the formula carefully; in high gravitational regimes it looks newtonian (obviously, e.g. solar system). MOND, by definition predicts keplerian curves when the galaxies are rotating quickly (high gravitation). You will find that ellpitical and lenticular galaxies are almost always rotating fast. it also can through EFE but i dont fully understand the math enough to explain that.
For galaxies, which are extended objects, the rotation curve is not Keplerian when you are well inside the galaxy: it first rises to larger radii, then levels off. But since the baryonic matter (stars, gas, dust) in galaxy is rather centrally concentrated, the rotation curve should start looking more and more Keplerian as you get further and further into the outskirts and outside the galaxy.
But that is not what we see. Instead, we see the rotation curves staying roughly constant with radius ("flat"); we call this "non-Keplerian". This is true for almost all galaxies, including ellipticals and lenticulars (this is a recent study of three lenticular galaxies: https://www.aanda.org/articles/aa/full_html/2020/09/aa38184-.... Note the rotation curves in the bottom panels of Figure 3: they do not at any point start decaying, let alone decaying as fast as R^(-1/2).)
Figure 5 of that paper (https://www.aanda.org/articles/aa/full_html/2020/09/aa38184-...) shows the observed rotation curves; it also shows the predicted curves if just the stars and standard Newtonian gravity were operating, with the dotted red lines. Note how these lines first rise to a local peak at small radii, and then decline to larger radii: this is a (quasi-)Keplerian decline. It fails to match the actual rotation curve at large radii.
The conventional response is to postulate some additional form of matter, distributed in a much more extended fashion than the baryonic matter (this produces the dashed black lines in Figure 5 of that paper). The MOND response is to modify gravity (or: to modify the acceleration due to gravity) such that it doesn't show anything like a Keplerian falloff at large radii, even at radii where the gravitating matter (assumed to be just the visible baryonic matter) is well inside.
In the case of the Solar System, the Keplerian decline starts right outside the Sun, where the acceleration is strong enough to be above the MOND threshold. But if you went far enough out and could measure the circular orbital speed, MOND would start to deviate from Keplerian. In the case of galaxies, the outer radii where the rotation curves appear "flat" are where the acceleration due to gravity is low enough for MOND to matter, and so the predicted MOND curves will not be Keplerian.
(I should perhaps point out that I'm a professional astronomer whose been studying galaxies, including lenticulars and ellipticals, for almost 30 years, so attempts to mansplain my field to me won't really impress me.)
Some of the "there's no DM" or "there's almost entirely DM" diffuse galaxies are likely due to measurement error in the distance to the diffuse galaxy, for example.
Cheers all. I think it’s interesting how many of us are seriously interested laymen on this topic. I think it’s fun and fascinating.
Neither are theories, but good luck coming away unscathed when mentioning this in the presence of ΛCDM dogmatists.
As soon as you have at least two observations that you put together into a batch, you are at a minimum suggesting "these observations are causally connected". You have theorized that suggestion. You did not arbitrarily group those observations. (it's not "my dog pooped this morning" and "the car started when I hit the gas this afternoon") That makes it a theory.
What you describe, the idea that two things are connected, is not a theory. That's a hypothesis. A hypothesis is a claim about the world, and it might not (yet) be equipped with an acceptable explanation for why it should be believed.
A theory would be a formula or equation or perhaps a process which is consistent with a set of information and allows scientists or mathematicians to calculate more information. It's a system whose consequences you can work out on paper, or in a computer, or in your head. But notably, a theory need not have any bearing on reality. You can develop a robust theory in all its mathematical glory and never find or expect to find anything like it out in the universe. It is a theory nonetheless, because you can work with it and explore it for it's sake.
Now, certainly, we have developed some theories of dark matter over the years and hypothesized that they are candidates for explaining the real world. There are many such theories. And, for each one, some scientists hypothesize that that one might be an accurate description of the world.
But, no, the idea of dark matter is not a theory.
a hypothesis is the model (alone) for how things might be
a theory is the hypothesis + corroborating observation
if you have a set of observations and put forth a hypothesis from it (versus a hypothesis that has no observations backing it), it is automatically a theory. it may not be a good one but it is one nonetheless.
Which is fine, but every physicist seems to just assume that it must be a "force", a "particle", or a "field".
It can be other things, including errors in the math, errors in the models, errors in the observations, invalid assumptions, etc, etc...
It's rather irritating to see the n-th experiment "searching" for some previously unseen particle while literally only one team thought of revisiting the maths to see if something was missed.
Hot dark matter would be a black body emitter - we would see it.
If it interacted electromagnetically then effects like the bullet cluster's gravitational lensing shouldn't happen.
And if it didn't interact gravitationally then we should see normal galactic rotation curves.
Hot dark matter would be stuff like neutrinos and axions which don't interact electromagnetically.
"Looks like matter" is not a property, this interpretation already presupposes a theory that excludes many others that are heretofore still plausible. Physicists tend to ignore those other options, I believe, because of a combination of natural human linguistic biases and the desire for certainty in explanatory models that drives many of us into studying physics. Some get too confident too early and start making dogma their entire academic personality.
And my average brain always thought and still thinks that instead of chasing these unicorn entities that still can't be found, maybe we should reconsider some things, as it seems to be the case presented here in this article.
That's basically what happened with the neutrino. Neutrinos were originally proposed in 1930 by Wolfgang Pauli to solve apparent violations of energy and momentum conservation in beta decay. He suggested that the missing energy and momentum were being carried off by some additional -- undetected and mostly undetectable -- particle. For a while, it looked like these proposed ghost particles might never be detectable, but Fred Reines finally managed it... in 1956, 26 years later.
So don't write off unicorn particles. Sometimes they're real, even if you have trouble detecting them.
Somewhat reminds me of aether...
There was a pattern in late-19th- through late-20th-century physics wherein someone noticed something weird, said "hey, if X were true, it'd be kind of weird, but it would explain it all", then people went out and looked for evidence of X. In many, many cases, people did indeed find X, some closely related X', or at least got strong evidence in favor of something else Y, which might have disproved X but at least settled the matter.
This has not happened with dark matter or dark energy. The questions still remain open, with no good evidence for any explanations.
So... what I'm saying is, don't think less of people for trying to explain things, just because they tried and it didn't work out yet. You're seeing the scientific method play out right now: there is a whole lot of wrong. There was a lot of wrong in the old days, too, but we weren't around to see it; only the successes got passed down.
The other problem is that nothing else really fit… until now. Science works, turns out.
I mean obviously not, I just don't understand the thought process behind coming to the conclusion that it's the professional physicists who must be wrong or have failed to reconsider something and not the layperson whose knowledge about the thing is dwarfed in comparison.
This is so fascinating. I think the principle applies to so much of the natural sciences. GR describes a set of rules (differential equations using tensors) that describe how matter moves in spacetime, and how it curves it. But outside of certain specific conditions (Schwarzschild etc), we can't (yet) use it to build useful models! We can use it to an extent to validate parts of models, but it leaves so much to the imagination. We are still using Newtonian models in cosmology, then applying GR effects like GEM piecemeal, and the time dilation effects in the article, where complexity and understanding allow.
We have these rules, but don't know how to use them to model! See also: Quantum mechanics and ab-initio chemistry. It's as if the universe is written in differential equations, but we are novices at how to use them.
But timescape wiltshire leads to a nice presentation:
https://www.nottingham.ac.uk/physics/documents/talesoflambda...
And without math, https://en.m.wikipedia.org/wiki/Inhomogeneous_cosmology
I wonder if he called it "timescape" as a reference to the star trek the next generation episode where small bubbles of space experience time moving at different speeds.
Of course they're just placeholders for things we don't understand, but my guess is that they are not any form of energy or matter at all, but a misunderstanding of the geometry of space or something similar.
Luminiferous aether was invoked to explain the ability of the apparently wave-based light to propagate through empty space. [1] Eventually we found evidence that contradicted that idea.
Dark matter is implied by gravitational effects which cannot be explained by general relativity unless more matter is present than can be observed. [2] We are searching for direct evidence, but haven’t found any yet.
Don't astronomers call elements like neon metals? Maybe cosmologists don't?
They will call that "baryonic matter".
What other people have been doing over the past 40 years is attempting to devise tests for these various dark matter candidates. We know, for example, through lensing observations, that MACHOs/brown dwarfs don't exist in the required numbers and that the neutrino mass seems too low. The problem, of course, is that there are only so many ways to try to observe matter that is truly dark.
I agree, though, that, in the end, it may be that dark matter will be an untestable hypothesis, just like quantum gravity or whatever.
This means all 3D points in our space are on the horizon itself, and the time dimension is the normal vector to that "surface" (3D manifold). It explains why space is expanding, because Event Horizons always only expand (excluding considering Hawking evaporation of course, which happens too slowly to affect things)
Relevant quote:
> "Still, some folks will stubbornly insist, there has to be something deep and interesting about the fact that the radius of the observable universe is comparable to the Schwarzschild radius of an equally-sized black hole. And there is! It means the universe is spatially flat."
He likely believes in the Big Bang too which is an absurd, and disproven theory. There are far too many mature galaxies that are far too old for the Big Bang theory to be correct.
You may be thinking of someone else. I'm not aware of Carroll having "his own theory" that he's "staked his entire reputation on."
In any case, he's explained his position, even in the quote I provided. He's simply describing what general relativity says about this. If you have some issue with it, you can respond on technical grounds, without needing to resort to ad hominem.
> He likely believes in the Big Bang too which is an absurd, and disproven theory.
Big Bang is not "disproven" - the Lambda-CDM model of the Big Bang is still known as the "Standard Model of Cosmology," and nothing has replaced it as a consensus among mainstream scientists.
> There are far too many mature galaxies that are far too old for the Big Bang theory to be correct.
The issue of galaxy ages has a number of reasonable explanations in the context of Lambda-CDM. One of them could simply have to do with age estimates, which is an area that suffers from limited observational data that's difficult to interpret. Recent work on the Hubble tension may help resolve that, e.g.: https://news.uchicago.edu/story/new-webb-telescope-data-sugg...
The idea that galaxy ages "disproves" Big Bang theory is at best, a misunderstanding of pop science hype, and at worst pseudoscience. That's not how science works, especially in cosmology where most evidence is very indirect and subject to interpretation.
The CMB originates from what's called the surface of last scattering. Prior to that time, density was such that photons couldn't travel very far without being absorbed. During that period, matter was in an ionized plasma state, consisting of free protons, neutrons, electrons, and some light ionized nuclei like deuterium, without any bound electrons. In this scenario, there were no objects bigger than a light nucleus. It would be impossible for stars or galaxies or even dust particles to form in that situation.
Reinterpretation would depend on what the evidence was. This isn't an area that we're particularly unsure of. There's a very comprehensive theory of the evolution of the early universe, supported by all the evidence we have for quantum theory. I recommend Steven Weinberg's book The First Three Minutes if you're interested.
When people still insist on believing the CMB proves it even when we now see fully formed galaxies at the edge of the observable universe, it's only because they're vested in that theory, and they know if it's wrong then they've been badly wrong for their entire lives. Only people with decades of vested belief in the Big Bang are hanging onto it for dear life, while open minded objective people correctly claim the evidence is against the Big Bang, and it was never anything but a wrong guess.
The Event Horizon theory doesn't postulate a "beginning" of everything, in the comical "it popped into existence" nonsense of the Big Bang. The EH theory doesn't try to establish a first-mover or uncaused-cause. It just describes how the universe is without trying to describe any "magical" beginnings. The Big Bang is a theory about magic, not a theory of science.
Can you point me to any papers about this? Preferably peer-reviewed.
The reason scientists do peer review is captured well by the Mike Tyson quote, “Everyone has a plan until they get punched in the face,” which we can rephrase as, "Everyone has a theory until they undergo peer review."
The point is that your theory is almost certainly wrong, but you won't find out how wrong it is unless you describe it in enough detail for others to check it.
That's just nonsense. My analogy about boxing is not shit-talking, it's pointing out what you're actually doing: talking a big game with no ability to back it up.
I'm doing you a favor by pointing that out, because if you somehow don't realize it, it might help prevent you from turning into a complete crackpot.
Go do an honest evaluation against the Crackpot Index: https://math.ucr.edu/home/baez/crackpot.html
I'd do it for you, but I can't even do that because your idea isn't documented.
[1] https://en.m.wikipedia.org/wiki/Big_Bang#Observational_evide...
Quick calculations say that ratio is 1.71:1 (https://rentry.co/k85wy696). I guess given the scale of the numbers having such a low ratio is interesting.
But my intuition says that in physics constants are scattered in a sort of logarithmic way, i.e. the orders of magnitude are uniformly scattered in some range. So small ratios between such constants not impossibly rare.
I may be full of shit though!
> discovering that the expansion of the universe was accelerating. They came to this conclusion by observing faraway exploding stars. These distant supernovae showed that the cosmos was getting bigger faster because the farther away the supernovae, the faster it appeared to be moving away from us.
This explanation always bothers me. After a long time, things that move faster WILL be farther away than things that move slower. Thats just the definition of speed. It does not, by itself, demonstrate acceleration.
What they really did was measure the distances and redshifts of dozens of supernovae and looked which energy contents of the universe could explain the observed relationship assuming that the Friedman-Lemaitre-Robertson-Walker metric accurately describes the universe. Turns out you need 70% of something whose density does not change with the expansion.
This is the original paper if Hossenfelder's summary of the explanation compressed in one sentence does not convince you:
https://arxiv.org/abs/astro-ph/9812133
For a derivation of the relationship between redshift and distance see any introdctory text on cosmology, e.g. chapter 8 of https://arxiv.org/abs/gr-qc/9712019 (he arrives at the equation on the last page).
Edit: This goes into more detail of matter species in sec. 1.5 and touches on the SN observations in sec. 1.7: https://www.thphys.uni-heidelberg.de/~amendola/teaching/adv-... (on an unrelated note: he was my PhD advisor)
Of course not. My comment is a quibble on the one sentence explanation. You seem to agree with me it's insufficient. Thank you for the additional resource.
If a dark matter alternative ends up being an accepted theory, then RelMOND stans are gonna be beyond smug, and well rightfully so I suppose.
Also, this is about dark energy, not dark matter
> Further notes regarding Superfluid Quantum Gravity (instead of dark energy)
As I understand it, most cosmologists still thing dark matter is the most likely candidate as it explains multiple different daya points unlike Mond.
There are also hypothesized particles that fit within the Standard Model that researchers are searching for experimentally.
Honestly, these articles are upvoted by people who know very little physics and think that dark matter is somehow a very mysterious idea.
One of my favorite sci fi concepts is a universe where the cosmological principle was false.
As it stands now, the cosmological principle seems false at every scale we look (with confidence decreasing in falshood slightly decreasing as scale gets larger). So that doesn't seem to be a "sci fi" concept, just a "sci" concept.
Or if it was true once (CMB-era) it sure as shit ain't true now.
There is a world of difference between " These Physicists Want to Ditch Dark Energy " and " Physicists Want to Ditch Dark Energy". One is about new model from some physicists and the other implying a conciseness around ditching dark energy.
edit: I didn't know that there is automatic re-write rules for HN. However the fact that the edited title is clickbait now regardless the reason. Just clarifying in case of this is considered an attack on the submitter.
In the plural it should probably convert "These" to "Some" rather than implying that "all physicists want to ditch dark energy."
Kidding, mostly. I do think it's an indicator of institutional issues with the site, its moderation staff and the motivations for keeping it alive. It wouldn't be surprising to me to find that many decisions were made by or for eccentric wealthy and/or smart people having a mild ego trip. "We're reducing the internet's toxicity via automated symbolic manipulation of media titles thus making the world a better place."