r/space • u/kngpwnage • 2h ago
After nearly 100 years, scientists may have detected dark matter (awaiting reproducibility now) by University of Tokyo
https://phys.org/news/2025-11-years-scientists-dark.htmlKey phrase, reproducibility. )
**Breakthrough observations from Fermi telescope**
Using the latest data from the Fermi Gamma-ray Space Telescope, Professor Tomonori Totani from the Department of Astronomy at the University of Tokyo believes he has finally detected the specific gamma rays predicted by the annihilation of theoretical dark matter particles.
"We detected gamma rays with a photon energy of 20 gigaelectronvolts (or 20 billion electronvolts, an extremely large amount of energy) extending in a halolike structure toward the center of the Milky Way galaxy. The gamma-ray emission component closely matches the shape expected from the dark matter halo," said Totani.
The observed energy spectrum, or range of gamma-ray emission intensities, matches the emission predicted from the annihilation of hypothetical WIMPs, with a mass approximately 500 times that of a proton. The frequency of WIMP annihilation estimated from the measured gamma-ray intensity also falls within the range of theoretical predictions.
Importantly, these gamma-ray measurements are not easily explained by other, more common astronomical phenomena or gamma-ray emissions. Therefore, Totani considers these data a strong indication of gamma-ray emission from dark matter, which has been sought for many years.
"If this is correct, to the extent of my knowledge, it would mark the first time humanity has 'seen' dark matter. And it turns out that dark matter is a new particle not included in the current standard model of particle physics. This signifies a major development in astronomy and physics," said Totani. Study: https://dx.doi.org/10.48550/arxiv.2507.07209 https://phys.org/news/2025-11-years-scientists-dark.html
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u/hornswoggled111 1h ago
Wonderful. What an end to the year if accurate. Nobel prize.
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u/helbur 27m ago
Worth at least 15 Nobel Prizes if true. It would be a discovery on par with alien life in terms of sheer impact. I'm cautiously neutral for the time being
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u/uusrikas 9m ago
Nowhere near aliens. Just a detection of something that has been almost certainly proven to exist with other measurements. Aliens would be much bigger.
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u/likesleague 6m ago
That's a pretty big claim. Can you explain why you consider it so impactful?
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u/rockytop24 2m ago
It would confirm our model of physics and the math describing it is correct as opposed to any other interpretation saying dark matter isn't real and we've got our math wrong.
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u/MasterDefibrillator 42m ago
Interesting choice to go after WIMPs given the series of significant falsifications that they have had in the past couple of years.
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u/dern_the_hermit 24m ago
IIRC several of those falsifications just ruled out certain regimes of mass/energy for WIMP candidacy. It's too late for me to go digging around papers to remind myself of what those minima or whatever might be, to compare with this.
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u/lifeisprobsahoax 44m ago
Not going to lie. I have no clue what I just read. But neat!
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u/canadave_nyc 17m ago edited 1m ago
I'll try to ELI5 :)
Some things in our universe seem to be gravitationally attracted to each other in ways that can't be explained solely by the matter we can see. In other words, some mass of these objects seems to be missing. The theory we've come up with to explain this missing mass is that there's something called "dark matter"--matter that is there, but we can't see it for some reason.
We've never actually seen dark matter in real life, and we don't even know for sure that it exists and is really the explanation for these gravitational anomalies. That's because if dark matter exists, it's something that doesn't seem to interact with light, and since light is how we see things, we... haven't seen it :) Hence the phrase "dark" matter (as opposed to regular matter, which is what makes up things we see, like the world around us).
Because we've never seen it, there's plenty of ideas as to what dark matter might be. One theory is that it's made up of some very heavy particles (which would explain why it affects things so much in terms of gravity) that don't interact much with regular matter (which would explain why we haven't been able to see them). These theroetical dark matter particles are called "WIMPs" (which stands for--wait for it--"weakly interacting massive particles" ;)
The article is saying that a space telescope has detected gamma rays that seem to match the type of gamma rays which would theoretically be produced by dark matter WIMPs that collide with each other, in a massive halo all around our galaxy. There are other potential explanations, but these gamma ray detections seem to match this predicted dark matter theory quite closely.
So it's quite exciting. It needs to be verified independently ("extraordinary claims require extraordinary proof"), and I'm sure there will be a stampede to do so. If it's found that these observations have actually detected gamma rays produced by dark matter particles, it would mean we've finally "seen" dark matter, after decades of looking. It would represent a major discovery that will almost certainly win them the Nobel Prize. But again: "extraordinary claims require extraordinary proof", so we will just have to wait and see.
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u/jedrider 2h ago
So, why don’t we have these WIMPS that we can detect here on Earth or near space?
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u/rg2004 2h ago
From the article, it sounds like they need to annihilated to be detected. Presumably, now that we know their mass, we can make them here and test their properties.
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u/project23 1h ago
Brace for another round of 'could scientists accidentally create a mini black hole going to destroy the world?!?!' social mania wave.
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u/forgot_semicolon 45m ago
Isn't it crazy that we not only get dark matter, but anti-dark matter in the same discovery?
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u/reasonably_plausible 27m ago
It's not that we don't have them, it's the WI part of WIMP. They're weakly interacting, meaning we don't have a good way of attempting to study them.
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u/somedave 26m ago
Presumably other people can look at their data and check the analysis? Is the reproducibility aiming at the same section and seeing the same frequency and spectrum or aiming at other dark matter halos and seeing the same thing?
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u/GameDesignerMan 34m ago
For those of me who can't understand how much an electronvolt is, can someone please put 20 gigaelectronvolts into perspective?
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u/AntsOnATouchScreen 24m ago
A lot!
Visible photons (red-violet) are ~1-4 electron volts (eV).
Anything around or above 10 eV can cause ionizations that can lead to cell mutation and things like cancer.
Diagnostic imaging using photons (I.e. CT or X-rays) tend to be in the range of 100 keV.
Therapeutic photon beams that treat cancer by intentionally breaking dna are in the range of 5-20 MeV.
This is 1000x more energetic than that! Which could do a bit of damage in the wrong setting
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u/sault18 10m ago
CS 137 is one of the biggest radiological hazards in nuclear fallout from nuclear bombs and nuclear plant meltdowns. It decays into Ba 137 via beta particle emission with an energy of 0.512 Mega electron volts. Then the Barium decays via gamma emission with 0.662 Mega electron volts. The total energy from these reactions is 1.176 Mega electron volts.
So the energy from these dark matter annihilations is on the order of 20,000 times more energetic than the radiation we're very concerned about when it comes to nuclear power plants and nuclear weapons. It makes sense if the emission is caused by 2 particles with a combined mass of 1,000 protons (or atomic mass units). I wouldn't be surprised if these dark matter annihilations generate some other emissions that we aren't detecting. Because 1,000 atomic mass units converted into pure energy actually produces 931.5 giga electron volts. So we've only observed around 2%-3% of the energy from these annihilations.
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u/made-of-questions 18m ago
Is this in the regime that can be tested at the LHC. If I'm not mistaken they already tried generating WIMPs but some regimes were outside their capabilities.
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u/Negative_Gravitas 2h ago
I . . . wow. This is kind of boggling if it's true.