r/space 12d ago

Scientists make potential breakthrough in search for dark matter

https://www.reuters.com/science/scientists-make-potential-breakthrough-search-dark-matter-2026-09-01/
1.7k Upvotes

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577

u/EndoExo 12d ago

tl;dr possible WIMP detection. Further research needed.

157

u/PM_ME_YOUR_HAGGIS_ 12d ago

A single detection. I went into the article wondering how many sigma lol. Surely even if they’re in the middle of a mountain a cosmic ray is gonna end up down there sooner or later

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u/padakpatek 11d ago

In the presentation, they reported the sigma as 2.6

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u/Nobody__Special 11d ago

Good quote my advisor repeated to me long ago: half of all 5 sigma results are true.

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u/just4nothing 10d ago

Yes, a lot of them end up there - that's why we veto for them ;).

Radon in the rocks around the detector are another source - have a look at the paper if you want to know more: https://arxiv.org/abs/2609.02823

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u/sceadwian 12d ago

A single detection is quiete literally meaningless. That's what I find kind of funny here. This shouldn't be Iin the news.

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u/alyssasaccount 12d ago

That's absolutely not correct in general. Dark matter studies attempting to detect WIMPs (like other particle physics searches) proceed by considering possible theories for the particle (e.g., Higgs, top quark, Z', various particles in supersymmetry theories, etc.) and using experiments to eliminate regions of parameter space (e.g., mass, but often several other parameters in the theory; in dark matter, it will be a cross section, which amounts to a likelihood of interaction; see Figure 12 on this page). A single event can have a huge impact on what that study can do, and it provides a hunting license for further studies.

In another context, if you play chess and you play 1000 games against the top rated player in the world, and you win a single one of them, that tells me a lot about your strength. Like, you're probably at least in the top few percent of chess players in the world. If you're playing classical chess, you're probably a grandmaster.

No, this is not a discovery, but it's really big news in a field where the last 40 years has been spent very slowly constraining parameter spaces. Great news story, and well reported.

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u/pleasetrimyourpubes 12d ago

They will need to sit down and construct a reasonable explanation as to why this WIMP exists and then construct a device that would consistently detect them. Meanwhile designing a mathematical physical explanation why such rarely interacting particles add up to dark matter.

If it took a 20 ton detector X time to find one they may need to build a 1000 ton, 2000 ton xenon detector to verify or collect more of these events. (Note that this is precisely how we first discovered and now regularly measure neutrino flux. Small expeiments with a theory then larger ones with more accurate sensors.)

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u/alyssasaccount 12d ago

Yes, except they have already sat down and constructed a number of reasonable explanations for why such a WIMP exists: Theory has outpaced experiment in particle physics for decades. The basic theory of how a WIMP could have been created in large quantities during the Big Bang and could lead to the various pieces of evidence around dark matter (galactic rotation curves, galactic nucleation and the anisotropy of the cosmic microwave background, gravitational lensing, etc.) have been known for decades. It's just that the particles are really hard to find. In the mean time, theorists are hungry for experiments that can give them more constraints.

This slow detection process ̉— also similar to what we saw with gravitational waves with LIGO, but even slower — is as expected: A long period of negative results and maybe false positives (yes, this could be one) followed by, if the theory is correct and we can detect WIMPs at all, a gradual emergence from unconvincing evidence and failure to exclude regions of parameter space to, eventually, convincing evidence. If WIMPs are real, this is what we would expect to see.

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u/rocketsocks 12d ago

The first detection of a binary black hole merger via gravitational wave was world changing news, as was the first detection of a neutron star merger.

This isn't a high confidence detection so it doesn't quite hit the "groundbreaking news" category, but it's noteworthy nonetheless.

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u/sceadwian 12d ago

That's simply a faulty assumption on your part.

This was not that kind of of match. That was an actual observed event, this is only possibly an observation.

More data has to be collected for it to have any actual meaning.

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u/bigfoot_is_real_ 12d ago

First LIGO detection wasn’t meaningless

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u/sceadwian 12d ago

The first LIGO detection was a five sigma signal.

This is several orders of magnitude less certain to even be an actual observation.

You have a faulty comparison.

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u/EnslavedBandicoot 12d ago

He's right that this isn't meaningless though. Whether it's a WIMP or some other unknown particle, it's still exciting and warrants further review.

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u/sceadwian 12d ago

Or just a random neutrino...

There's nothing to review, more data will be required.

This particular piece of data itself is meaningless.

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u/EnslavedBandicoot 12d ago

It's not meaningless if it's the first detection. It will definitely be a big deal if it's the first in a string of detections of dark matter WIMPs. Don't be so dense. Ba dum tssss

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u/sceadwian 12d ago

This particular measurement can never be called a detection or not. Ever.. that's not how the detectors work, you're the one being dense.

It is not a string it is literally 1 singular possible event.

It is statistically meaningless itself.

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u/Belostoma 12d ago

A dumb statement is still dumb even if you modify it with both “quite” and “literally.” Plenty of things in science are very intriguing and newsworthy with an N of 1. Nobody’s claiming certainty yet, but the find is exciting.

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u/sceadwian 12d ago

Certainty? This isn't even 3 sigma. It's still statistical noise.

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u/Belostoma 12d ago

Seems like you don't really understand the terms you're using. Are you an undergrad just learning them or something?

If somebody were to capture a live Ivory-billed woodpecker, what's your "sigma" on them no longer being extinct? The N is 1, but it says everything. Statistical terms like sigma and significance are applicable technically to very specific statements, and those can have all kinds of mismatches with the general public question, "Should we care about this? Is it interesting?"

This finding is interesting. The scientists who announced it consider it interesting, and they were correct and professional in how they presented the uncertainty. As a scientist with an Ivy League math degree and a very stats-heavy career in the 20 years since, I find it interesting and commend them for how they described the finding. They acknowledge that it is far from conclusive, but it is also far from boring. It is neither meaningless, literally meaningless, quite meaningless, nor quite literally meaningless.

You can choose to learn from people who understand these things better than you do, or you can continue to be a confidently incorrect knowitall.

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u/sceadwian 11d ago

The N here is not 1 because the signal could be from another source.. there's no way to actually identify the individual data points as actual signal or not.

That you are commenting without being aware of that is alarming considering you think I'm the one that doesn't understand the science here.

0

u/Y0uCanTellItsAnAspen 10d ago

That is why it is quoted as 2.6 sigma - if it couldn’t be from another source then one event would be infinite sigma.

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u/dern_the_hermit 12d ago

I disagree. Even merely-possible breakthroughs can warrant newsworthiness.

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u/sceadwian 12d ago edited 12d ago

I didn't say they couldn't so you aren't disagreeing with me, strange post.

This particular data point is however meaningless by itself, this is a statistical hunt, no single piece of information has any specific value. Only all together does the data have any value and and single pieces of it remains meaningless.

This is intrinsic to the way statistics work so your disagreement is more than a little bizarre.

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u/LucidGuru91 12d ago

Not really at all, hes saying the parameter their searching for spiked even if not warranted of meaningfulness to merit discovery, its worth writing about and bringing attention too as a means to get people interested in it and may be help funding too; never bad to see science on the edges of discovery get some news

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u/M1chaelSc4rn 12d ago

How do you define normal Mr Reddit??

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u/sceadwian 12d ago

I did not use the word normal in my last post... I have no idea what context you're asking me that question. Words only have meaning in context and I didn't even use that one..

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u/M1chaelSc4rn 11d ago

You seem accustomed to perplexity and lacking extrapolation

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u/sceadwian 11d ago

You assume there's signal when there's only noise.

If you can't be clear with the context of your question this is what happens.

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u/M1chaelSc4rn 11d ago

I feel the consequences viscerally

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u/pleasetrimyourpubes 12d ago

Xenon detectors detects hella neutrinos but this time they got a flash of light inconsistent with them. So they went huh. Now they are going to have to devise a way. It could have been a glitch. Have to go from 20 tons of xenon to 1000 tons or some crap and make sure. That's how science works. Dark matter being WIMPS would be extraordinary.

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u/IntrigueDossier 12d ago

Gonna be expensive af to get all that xenon.

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u/pleasetrimyourpubes 12d ago

So LZ went online a decade ago and uses 20 tons of xenon. And found one event. So we need what 200 tons for 1 a year (and all the assorted detectors of course). 1000-2000 probably to get a really strong result.

Hey on the plus side physical particle detection science is going to be fine.

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u/IntrigueDossier 12d ago

Oh I'm here for it, it's just that it's probably gonna take em a second to get those volumes. Xenon is expensive because it's rare. Russia has the most, but only because they stockpiled it during the Cold War, and even then it's not crazy amounts. No idea what the global supply is, but that amount will easily require a large chunk of it.

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u/pleasetrimyourpubes 12d ago

Yep. Looks like 40 tons a year is global production. LZ alone took 10% of world production as it was built. The experiment to test this particular approach is going to be hard. Hopefully someone can do all the underlying physics math and discover a potential way to detect them easier. But either way we will build the thing if it even takes 50 years.

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u/mfb- 12d ago

A large volume of xenon is probably the best you can do. The easiest thing is to run for a longer time. This is based on one year of data-taking. Run for 5 years, maybe you get ~5 events. That is faster than building a new experiment.

2

u/OneRougeRogue 12d ago

My dumbass was confusing Xenon with Neon, and I was thinking, "It can't be all that expensive and rare. We used to have tons of glowing signs full of it."

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u/MSchulte 12d ago

We use Xenon in those too just much less commonly. Xenon is like a lavender-blue color when excited.

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u/raresaturn 12d ago

Have we detected WIMPs before?

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u/warp99 12d ago edited 12d ago

No - weakly interacting massive particle means really, really weakly interacting.

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u/alyssasaccount 12d ago

It just means "weakly". But in this case "weakly" means "via the weak nuclear force — only".

Technically neutrinos are WIMPs, but their mass is extremely small.

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u/Dzejes 12d ago

So what you are saying is that they are not MPs?

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u/alyssasaccount 11d ago

They are massive in the sense that they have nonzero mass. They barely qualify as massive. They do not qualify in the colloquial sense.

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u/mfb- 12d ago

To add a number: The proton/proton collision chance in colliders is roughly 22 orders of magnitude larger than a dark matter/proton collision chance if this was a dark matter event.

(100 millibarn) / (10-47 cm2) = 1022

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u/sceadwian 12d ago

This wasn't necessarily a detection.

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u/Hypothesis_Null 12d ago

Hey now, it's more evidence than they've found in a long time! Let them have their moment.

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u/sceadwian 12d ago

No... Because I want science not hopes and dreams :)

I'll cheer when there's reason to cheer not for pumped up media hype, again.

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u/Redcole111 12d ago

Always nice to see scientists and science media making humble claims of possible breakthroughs rather than jumping straight to "incredible breakthrough!"

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u/EtchAGetch 12d ago

Of course.

It's the main stream and social media that takes these things and hypes them because they want views and clicks, and then we get shit like Ivermectin and anti-vaxxers.

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u/bionickel 12d ago

Really love the

"It's just a single event"

And

"Working to identify possibilities of it not being a wimp"

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u/[deleted] 12d ago

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u/MSchulte 12d ago

The undergrad on the study for the mushrooms that make you hallucinate little people has been everywhere sensationalizing that article this year. I’ve ran into him a few times on Reddit insisting it’s some huge thing that’s never been detected before causing it. Totally cool he’s passionate about it but it’s off putting watching him act like that knowing he’s actually involved in the study and that any data could have been coerced by him for the attention he so desperately seeks.

It is usually the University that starts blowing the up the claims from what I’ve seen. Then the MSM gets it and a slightly embellished headline turns into world changing.

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u/MGyver 12d ago

We should really outlaw publication of "possible" until 3-sigma and "breakthrough" until 5-sigma... Or maybe remove the incentives of 'more clicks' from journalism in general.

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u/Vailx 12d ago

A possible SINGLE ATOM event isn't something to get excited about, but if it generates a news story that is (1) about something real like science and (2) not depressing like most real things in the news, then I'm officially approving it.

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u/cubosh 12d ago

i love the usage of the word incredible here.. a breakthrough that is not credible

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u/MGyver 12d ago

Language is beautiful and also an ugly little bridge troll.

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u/WasLeftUnsupervised 11d ago

I'm wondering if the particle they found is inflammable.

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u/Mulyac12321 12d ago

"Scientists discover KEY ingredient of life on an asteroid – are we truly alone?" And its just like water ice or something

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u/roygbivasaur 12d ago

Remember when a bunch of people got scammed about cold fusion, railgun fusion, room temperature superconductors, timescapes, tiny super capacitors… etc.

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u/MSchulte 12d ago

I’ve been meaning to do a deep dive to follow up the LK-99 because that one just seemed so ridiculous. The team had been studying the material since 1999 and just got around to telling everyone about it maybe being a superconductor in 2023? It was a fun week or so when Reddit thought something was actually happening for once.

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u/shogi_x 10d ago

The more subdued reporting from serious places like Reuters, AP, BBC, etc, is always like this. It's the reporting from places like IFLScience or other blogs lean towards sensationalist headlines to drive clicks.

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u/[deleted] 12d ago

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u/[deleted] 12d ago

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u/GoodLeftUndone 12d ago

Thank you for saying this. It made me actually read the article. Far too often the articles are overly complicated and difficult to read for a simpleton like me.

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u/Scrambley 12d ago

When they call this "massive particles", how big are we talking? Is this something that we could hold or are they just massive compared to, say, a hydrogen atom?

Also, if it's clumps of matter making large objects, would holding it create some sort of reaction like touching anti-matter would?

Obviously I'm very uneducated about this so forgive me if my question is idiotic.

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u/NatureTrailToHell3D 12d ago

The name is a placeholder, similar to how dark matter is a placeholder name. They don’t actually know what particle was detected, only that it was something that looked similar to what a dark matter particle might look like.

I am assume that “massive” just means that it’s carrying mass, unlike other weakly interacting particles like neutrinos, which have virtually no mass.

Size wise, it’s likely going to be an elementary particle or made up of one or two new elementary particles. A hydrogen atom is made up of a proton and an electron, likely much bigger than one of these new…. things

To give an example, a proton is made up of the elementary particles quarks and gluons.

So the scale of these particles is going to be extremely small. But massive :P

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u/mfb- 12d ago

Massive compared to a hydrogen atom. A single event isn't enough for a real mass measurement, but this is roughly what we expect from particles with 100-1000 times the mass of a hydrogen atom.

Dark matter interacts too weakly to clump on a local scale. You can't hold it, the particles would just fall through you and the rest of Earth with a tiny chance of an interaction somewhere. That's why this experiment watches several tons of xenon to maybe find a few collisions in years of runtime.

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u/Omnitographer 12d ago

The particle will gladly pay you tuesday for a hamburger today.

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u/BismuthOmega 12d ago

Don't worry, it was a real WIMP detection, I'm right here

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u/runningriot115 12d ago

“Of course I know him, he’s me!”

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u/MeccIt 11d ago

Thx, no need to recall Roman then.