Study: Dark matter doesn't exist, the universe is 27B years old
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New research suggests that our universe has no dark matter - https://news.ycombinator.com/item?id=41760006 - Oct 2024 (36 comments)
It’s not a scientific theory unless it’s testable. I’m going to withhold judgement on this and take it for what it is: an interesting idea, and nothing more.
The issue that I have with people calling dark matter a theory is that they think it requires matter to solve. It doesn't. MOND is a dark matter theory. It explains(in part) why it appears as though undetectable matter is present in galaxies causing disc velocity to not match expectations.
Worth noting, too, that the paper outlines several possible experiments. It also specifically mentions some relative shortcomings of the model, and lists existing observations that they haven't tried to reconcile with it yet.
> “There are several papers that question the existence of dark matter, but mine is the first one, to my knowledge, that eliminates its cosmological existence while being consistent with key cosmological observations that we have had time to confirm,” Gupta confidently concludes.
The answer to Fermi is that there's no point to expanse, which culls the effort given enough time (the exploration effort is very expensive in exchange for rapidly diminishing returns for most civilizations). Intelligent life that makes it to our stage and beyond chooses to go inward long before it spreads super wide outward. There is vast, unlimited, easy, lower cost satisfaction inward (virtual space), there is nothing of great value outward at any reasonable cost of resources and time (humanity doesn't grasp this widely yet, it's still in the naive, neighborhood exploration stages). The only thing out there is disappointment, once you discover it's almost all low value repetition (extraordinarily vast repetition of very low value entities).
Tell someone in the 1600s about the concept of cellphones and they would say it’s impossible to ever instantaneously communicate with someone around the world.
It’s so energy intensive with our current technology, which isn’t really an answer to fermi.
I don't know that they would.
In the 1600s, they'd just invented the printing press, so communication was already undergoing a fairly massive change. A book that once took a lifetime to copy could now be printed in three days.
From there, it's a short walk to "this book that used to take a lifetime to copy can now be printed more or less instantly." And from there, we can start laying the groundwork for what we would eventually call telecommunications.
Cell phones rely on technology that people in the 1600s hadn't discovered yet. Interstellar travel would require us to not only discover new technologies, but technologies that actively violate what seem to be pretty hard physical laws.
If the speed of light really is a universal maximum, and something like an Alcubierre warp drive isn't possible, leaving this solar system is vanishingly unlikely.
You say that they saw books get printed faster, so they could conceive communication getting so fast it’s instant, despite their knowledge being limited to physical material.
By the same logic, couldn’t I say we have theorized wormholes and have already seen objects (like black holes) warp time and space? Therefore maybe we can warp space to travel, rather than literally needing to go faster than light?
I think it’s easier for us now to conceive the idea that one day we could make a wormhole than it is for people with no concept of radio waves to conceive the idea of a cellphone.
Plenty of empires (e.g. the Byzantines) had chains of fire signal towers (IIRC some had mirror signal towers). That's not instant, but it shrinks weeks of delay down to an hour, albeit with just half a bit of information. And the concept of going up a sufficiently tall mountain and being able to see a signal on the other side of the world is comprehensible to basically anyone (it's not physically possible, but they didn't necessarily know that).
Imagine if Mars and Venus were just habitable from the start, with plants, animals, and resources. We would probably have colonies there. Some intelligence somewhere probably had such a predicament.
We're not smart enough — collectively — to recognize we need to work on our feelings... even if our collective existence depended on it.
Source: Points at the geopolitical theater. (What a shame that our dumb systems and shallow leaders allow for so much hurting over petty squabbles. It's deplorable.)
If there are many universes (multiverse), then it's plausible only 1 instance of life forms in a few of them, and we might be the only life in the entire visible universe.
Is there a name for this theory?
I share this because I frequently see assumptions that there must be other life somewhere.
Anything that contradicts Special Relativity requires an exceedingly compelling argument or preponderance of evidence in favor, and Tired Light does not have it.
My (naive) assumption reading the article was that he wasn't proposing that a photon loses velocity over long distances, but that the value C was not constant on a multi-billion year time horizon. I don't see an easy way to prove that it is not changing if the rate of change is functionally unobservable.
But, maybe I am way too uniformed to speculate on this.
What you do have is a vast amount of data in the obseravable universe. So for a theory to be valid, it needs to not contradict all that out there which we can see. Or if it does contradict it, it needs to explain why that is and not contradict other things.
Often, as with particle physics, we're limited by what we can see, so we need new technologies (such as the JWST) to give us greater insights. Just as with modern particle physics, in a lot of cases this helps to reduce the size of error bars in observations or hypotheses, which then helps to reduce the problem space and weed out theories that then fall out of these error bars.
This is why you can have several competing theories at once (for example, various alternatives to dark matter). Some may be more popular than others, or may be more likely than others, but they stay on the table until actually disproven[1].
(Have an astrophysics degree, not a professional astrophysicist)
[1] Although as far as I was aware, Tired Light was actually considered off the table.
[1] https://news.ycombinator.com/item?id=39726388
Dark matter and cords theory are still imperfect working draft compared to other paradigms.
Unless you can link to a systematic study proving the CCC+TL is flawed there is no guarantee you are on the good side of scientific progress. Flat earthers where once convinced they were not on the side of crackpotery.
> there is no guarantee you are on the good side of scientific progress
I know, but I'm very confident. To quote Carl Sagan: 'It pays to keep an open mind, but not so open your brains fall out.'
> We’ve always been taught that the fundamental constants of nature — like the speed of light or the charge of an electron — are unchanging. But what if they aren’t fixed after all?
I mean, sure, what if? Honestly, if you can vary things like gravity, I don't think you need any additional components to explain the dark matter observations.
> The CCC+TL model needs to provide testable predictions that can be confirmed or refuted through observations and experiments
This step is important!
Ok, so dark matter generally: this YouTuber [1](physicist/physics PhD) notes that there are many theories that explain the dark matter observations. But to her, "dark matter" is the data that we need to explain.
Essentially: we have a bunch of weird observations where it looks like there's way more matter than we see. But the actual explanation for what it is, there are tons of those. So throw one more in the pile (this one says "oh there's no extra matter, the universal constants are different over there and light maybe moves slower as it travels farther")
> Admittedly, the CCC+TL model is significantly more complex to work with than the ΛCDM model.
[ ] It cannot explain galaxy rotation curves across all galaxy types.
[ ] It fails to account for gravitational lensing observed in galaxy clusters.
[ ] It cannot explain the Bullet Cluster observations where dark matter appears separated from normal matter.
[ ] It is inconsistent with the cosmic microwave background anisotropies.
[ ] It cannot explain the large-scale structure and formation of the universe.
[ ] It introduces arbitrary parameters without physical justification.
[ ] It lacks a sound theoretical foundation or violates established physics principles.
[ ] It fails to explain the observed velocity dispersions in dwarf spheroidal galaxies.
[ ] It cannot account for empirical relations like the Tully-Fisher relation.
[ ] It cannot be tested or falsified by current or near-future experiments.
[ ] Your claims are unfounded or exaggerated.
——
I’m not a physicist, and cannot fill this in, but I thought I’d provide the template for the first physicist who turns up.
you could argue the same about dark matter/energy.
> It cannot be tested or falsified by current or near-future experiments.
Did we actually directly observe dark matter or dark energy now?
Well, not really. The physical justification is, the multitude of observations that appear consistent with the theory that there is some form of matter out in space that does not interact with photons. It's not something someone just had a dream about one night - it's a real-world observation, with telescopes.
If, tomorrow, a laboratory discovers a new or existing particle that is able to actually, or even just apparently, avoid interacting with photons and matter, then dark matter could be done and proven.
By contrast, most dark matter competitors require us to rethink large swathes of what we know about physics and cosmology. That doesn't mean they're necessarily wrong, it just means the bar of skepticism is a bit higher.
This is it. Everything points towards it being some kind of invisible matter. Scientists know that the very idea is preposterous!
But you can't make up some 'cleaner' hypothesis without also holding that idea up to the same standards as Cold Dark Matter, and to date they have tended not to.
Claiming physics isn't uniform throughout the universe is more problematic than positing the existence of dark matter/dark energy. Lacking any evidence for either position, the principle of Occam's Razor informs us to stick with dark matter/dark energy.
One of the purposes of exercises such as this is to get people thinking of new ways to falsify existing models. So far, dark matter/dark energy are in remarkable alignment with observations. Falsifying either of these ideas would be huge.
They didn't say it existed.
They just said the existence of Dark Matter seems to be more likely than non-uniformity of physics throughout the universe.
Dark matter is a label for "whatever it is that causes the extra gravitation observed across multiple scales in the universe without also causing other indications of matter interaction like photon emission."
These are easy-to-hold handles for the collection of observations for phenomena we know to exist. We don't know the cause, but we know these things are occurring in the universe because we have demonstrated their existence through repeated observation.
Saying the laws of physics may be different in different parts of the universe is a statement that so far can't be substantiated, and we've been trying for over a hundred years now, is far more problematic. That's a dire option that we don't desire to pursue unless we're absolutely forced to - and we're not being forced to.
Between the two options we're going to stick with dark matter/dark energy until evidence suggests otherwise, or until a better, and simpler, idea comes along.
Nothing from the observable universe, just bundling all the mathematical loose ends together and stashing them under the rug.
So to my point, we are not "seeing" dark matter anywhere at all... What we have is a failure mode in our current models to explain the phenomena we see. And to fix it they plug in magic invisible heavy stuff. Literately a chunk of math to balance equations in the rotations of galaxies.
Yes, cold dark matter is something conjectured to explain what we see, because we see these irregularities and we need something to explain what is causing them. If we weren't seeing those irregularities we wouldn't need it.
>> What we have is a failure mode in our current models to explain the phenomena we see.
The thing is, you don't know that, and that concept has already been thought about many times over.
What is surprising about CDM in particular is that it is ridiculous and yet it survives observation and theory better than every other hypothesis to date. It is more intuitive that the mathematical equations are wrong, or they've measured something (like the age of the universe) wrong, or there's some kind of effect that hasn't been accounted for. Yet after testing all that, CDM fails to be thoroughly disproved. The vast majority of evidence points to it being a real thing. If it looks like a duck and it quacks like a duck...
I don't think it's appreciated enough that astrophysicts do know that this is weird. That's why it's so interesting.
However, you need to come up with a competing theory that actually holds up to rigor. It's no good saying "it must be this" without any supporting evidence to support it. It's simply a guess, sci-fi, not science.
Yes, it's entirely possible that it will be explained by some part of physics we currently have no knowledge of. Some addition to the standard model, perhaps, or some miniscule effect that falls out of quantum gravity, whatever that may be. But those things aren't even a hypothesis at this point, just pure speculation without justification.
> The CCC+TL model predicts the age of the Universe as 26.7 Gyr against the generally accepted value of 13.8 Gyr. This is of deep concern and needs the model validation against multiple observations, including BAOs, CMB, Big Bang nucleosynthesis (BBN), and globular cluster ages. Our focus here is on BAOs.
I am not in academia and therefore am not qualified to have strong opinions on any of this, but I do like the idea of papers not swinging for home runs all the time by explaining everything, and instead being happy with hitting a single by proposing something intriguing and asking for others to chime in.
That's not true though. It says in its abstract that it can fit the Type Ia supernovae Pantheon+ data as accurately as the ΛCDM model, and also fit the angular size of cosmic dawn galaxies observed by the JWST. It is the data produced by the JWST that has led to this model.
The article goes on to say:
> The galaxies observed in the early Universe, some less than 500 million years after the Big Bang, appear to have shapes, structures, and masses similar to those in existence for billions of years
It was only nine days ago, and here’s the next one. Yet, we have several fields that are only indirectly coupled to EM — neutrinos come to mind - and if you graph the fundamental fields you get a rather sparse graph.
It should be a surprise to no-one that there are disconnected segments.
It seems dark matter and dark energy exist to balance deficiencies observed in our current understanding of particle physics applied to a cosmological model, particularly for observations that span vast distances extremely far away. From a purely logical perspective we should anticipate great deficiencies the further away we look because our entire understanding of the universe is derived from observations of various EMF transmissions only and only from Earth, or near Earth in the case of JWST. That is an exceptionally limited perspective. We have much to learn and more evidence to gather before conflating one avenue of science into a practice more akin to a religion.
"Spacetime" also does not exist. Time doesn't exist as a force of nature or tangible entity, it's nothing more than a subjective measurement. It exists like your height measurement exists, or the measurement of four meters of distance from you to the wall exists. The matter contained in the space of distance being measured exists, and the events between (subjective) time measurements existed, time itself does not exist. You can measure your height from the ceiling to your head (impractical but you can do it). You can measure time based on Mars going around the Sun. Neither entity exists (your height, nor time; both are subjective based on the anchor chosen). It would be silly to think height measurements are a tangible force of nature, we'll call it HeightSpace, now we must discover how it rules over the universe and seek to observe its magic principles.
The bogus nature of "spacetime" has held back multiple fields for many decades. It has wasted a generation of brains that fell for it.
You can also measure it by using something non-subjective, like atomic state oscillations that are identical anywhere in the universe. You can then use this as a counter while watching entropy increase, and see that you are moving in a single direction as those oscillations tick.
That doesn't leave much room for subjectivity at all.
We don't yet know whether time is emergent or fundamental. It most certainly exists.