{"id":587851,"date":"2026-09-02T10:36:20","date_gmt":"2026-09-02T10:36:20","guid":{"rendered":"https:\/\/www.newsbeep.com\/nz\/587851\/"},"modified":"2026-09-02T10:36:20","modified_gmt":"2026-09-02T10:36:20","slug":"dark-matter-flash-of-light-gives-scientists-burst-of-inspiration","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/nz\/587851\/","title":{"rendered":"Dark matter: Flash of light gives scientists burst of inspiration"},"content":{"rendered":"

\"Angus<\/p>\n

September 2, 2026 \u2014 12:01am<\/p>\n

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Examine, a free newsletter covering science, is sent every Tuesday. You\u2019re reading an excerpt \u2013 sign up to get the whole newsletter in your inbox<\/a>.<\/p>\n

Sometimes it feels as if all the fundamental questions about existence have been solved. Then you remember dark matter.<\/p>\n

This unknowable substance constitutes as much as 85 per cent of all mass in the universe, and yet we cannot see or directly measure it, and we don\u2019t know what it\u2019s made of.<\/p>\n

\"ScientistsScientists believe dark matter underpins the structure of the universe.KIPAC\/SLAC National Accelerator Laboratory<\/p>\n

But the structure of spiralling galaxies, the make-up of the cosmos, and indeed our very existence only make sense if the universe is woven with an undiscovered, invisible essence, holding it all together like a secret skeleton.<\/p>\n

Needless to say, dark matter is the greatest scientific mystery of our time.<\/p>\n

That\u2019s why physicists are intensely excited about a tiny spark of light detected in a pool of liquid xenon in the depths of an abandoned gold mine.<\/p>\n

The data is limited and fresh, and scientists are duly cautious. But there is a possibility this newly reported signal could be the first-ever detection of dark matter.<\/p>\n

How do we know dark matter exists?<\/p>\n

Fritz Zwicky was an unconventional and at times unpopular scientist who once said of his more orthodox colleagues: \u201cAstronomers are spherical bastards. No matter how you look at them, they are just bastards.\u201d<\/p>\n

The Swiss stargazer was investigating the Coma galaxy cluster in 1933 when he realised the galaxies were rocketing around each other at 2000 kilometres per second \u2013 so fast they should have been violently flung away from each other.<\/p>\n

\"TheThe structure and speed of galaxies don\u2019t make sense unless they contain far more mass and gravity than they appear to have.AP<\/p>\n

He calculated the galaxies, to summon enough gravity to stay together, must have 400 times more mass than they appeared to have. What was providing this invisible gravitational glue? He proposed the existence of dark matter.<\/p>\n

Zwicky\u2019s theory was treated as zany. Then American astronomer Vera Rubin spied another anomaly in the 1970s.<\/p>\n

Stars on the outer edge of a galaxy should orbit much more slowly than those at the centre. But Rubin discovered the outer stars of a galaxy travelled just as fast as those closer to the centre.<\/p>\n

The visible matter in the galaxies didn\u2019t have enough gravity to hold on to these distant, fast-spinning stars. Something else was holding on to them. Rubin concluded: \u201cWhat you see in a spiral galaxy is not what you get\u201d, and that dark matter must be real.<\/p>\n

Now astronomers can see how light is warped in space by gravity emanating from dense, invisible regions of suspected dark matter.<\/p>\n

The image below shows galactic gas highlighted in pink, while the blue areas show regions of intense gravity scientists believe can only be explained by dark matter<\/a>.<\/p>\n

\"TheThe Bullet Cluster, a pair of galaxy clusters that collided. Normal matter is shown in pink, suspected dark matter in the cluster shown in blue. This observation has provided one of the clearest direct examples of dark matter.NASA<\/p>\n

But that\u2019s a shadow of a shadow. In the race to truly detect dark matter, instead of looking up through telescopes, we\u2019re burrowing deep into the Earth.<\/p>\n

The deep detector<\/p>\n

Dark matter doesn\u2019t emit or reflect light, and it barely interacts with normal matter. We also don\u2019t know what it\u2019s made of. So how do we find it?<\/p>\n

Dr Theresa Fruth, a dark matter hunter from the University of Sydney, helped design and construct one of the best dark matter detectors on Earth, called the LUX-ZEPLIN (LZ) experiment. About 250 scientists and engineers are participating in the project.<\/p>\n

\"Dr\u00a0TheresaDr\u00a0Theresa Fruth, from the University of Sydney, preparing to descend to the LZ detector in South Dakota.Theresa Fruth<\/p>\n

\u201cIt\u2019s basically a big bucket of liquid xenon,\u201d Fruth says. \u201cXenon is a trace element in the air around us, and it\u2019s a noble gas. But if you cool it down enough, about minus 100 degrees, it\u2019s a really dense liquid.\u201d<\/p>\n

Any skerrick of radiation might mimic dark matter and must be banished.<\/p>\n

\u201cXenon is good because you don\u2019t have any long-lived radioactivity naturally in the xenon. It decays away and you can have this very clean, very quiet liquid.\u201d<\/p>\n

\"TheThe LZ detector was moved 1.5 kilometres underground into a gold mine to shield it from cosmic rays.Matthew Kapust\/Sanford Underground Research Facility\"ResearchersResearchers assess LZ\u2019s central detector while it is wrapped in foil.Matthew Kapust\/Sanford Underground Research Laboratory
\n\"LookingLooking up into the LZ outer detector used to veto radioactivity that can mimic a dark matter signal.Matthew Kapust\/Sanford Underground Research Laboratory<\/p>\n

The ultrapure liquid xenon is contained in two tanks of medical-grade titanium and teflon, in turn encased by more than 250,000 litres of water for extra shielding.<\/p>\n

The entire thing is entombed in an abandoned gold mine in South Dakota, 1.5 kilometres underground, to protect the detector from cosmic radiation lashing Earth from space.<\/p>\n

In theory, if a skerrick of dark matter hits this pool of xenon \u2013 one of the stillest, quietest, most stable places on Earth \u2013 at the right angle, it would spark a tiny flash of light.<\/p>\n

On Wednesday, at midnight, scientists reported a flash.<\/p>\n

Finding WIMPs<\/p>\n

The LZ experiment is designed to detect weakly interacting massive particles, or WIMPs, one of the leading theories for what dark matter could be made of.<\/p>\n

WIMPs are thought to be heavy, slow-moving subatomic particles between 10 and 1000 times heavier than a proton.<\/p>\n

Scientists think they might be constantly passing through the Earth like ghosts.<\/p>\n

\"WhenWhen a WIMP collides with a xenon atom, the xenon atom emits a flash of light and electrons.Greg Stewart, SLAC National Accelerator Laboratory<\/p>\n

If one of these WIMPS struck the nucleus of a xenon atom in the LZ detector, theoretically, this would unleash a tiny flash of light. Five hundred photomultiplier tubes in the tank set-up are tuned to pick up any flashes.<\/p>\n

Scientists pore over the resulting data to see whether flashes might be explained by stray radiation given off by the material of the detector itself, or some other rogue background ray.<\/p>\n

Now they have reported a flash that, as yet, cannot be explained by a background signal: a possible hint of dark matter.<\/p>\n

\u201cWe don\u2019t really know what to do with that because we\u2019re so used to not seeing anything,\u201d Fruth says. \u201cWe usually make these jokes about how we\u2019re not seeing anything better than anyone else.<\/p>\n

\u201cThe moment you see something and you don\u2019t quite know yet what it is, it\u2019s very exciting, but also a little bit scary.\u201d<\/p>\n

Aussie detector in the hunt<\/p>\n

The finding is below \u201c5-sigma\u201d significance, which in physics lingo is the level of statistical confidence needed to report an actual discovery.<\/p>\n

The LZ flash sits at 2.6 sigma, which means there\u2019s a 0.5 per cent chance the flash could be due to a known background signal rather than a WIMP.<\/p>\n

\"TheThe dark matter lab under construction a kilometre underground at the Stawell Gold Mine in 2021.Joe Armao<\/p>\n

The scientists are releasing their data so that other dark matter hunters can analyse and try to explain it, so we\u2019ll know more about this detection in coming months.<\/p>\n

Meanwhile, the LZ detector team is waiting patiently for another event, which could help refine that sigma number. Should further data push the statistical firepower higher, we could be at the start of a historic moment in science.<\/p>\n

Related Article<\/p>\n

Fruth is now working on another dark matter detector running in a gold mine in Stawell<\/a>, north-west of Melbourne, made of ultrapure crystals rather than xenon.<\/p>\n

The type of matter we can see and detect is only a fraction of existence, and yet look at all we\u2019ve made of it.<\/p>\n

Once we unlock dark matter\u2019s secrets, Fruth wonders, what else might we learn?<\/p>\n

Examine, a free newsletter covering science, is sent every Tuesday. You\u2019re reading an excerpt \u2013 sign up to get the whole newsletter in your inbox<\/a>.<\/p>\n

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\"AngusAngus Dalton<\/a> is the science reporter for The Sydney Morning Herald.Connect via X<\/a> or email<\/a>.From our partners<\/p>\n","protected":false},"excerpt":{"rendered":"September 2, 2026 \u2014 12:01am Save You have reached your maximum number of saved items. Remove items from…\n","protected":false},"author":2,"featured_media":587852,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[24],"tags":[111,139,69,393,147],"class_list":["post-587851","post","type-post","status-publish","format-standard","has-post-thumbnail","category-physics","tag-new-zealand","tag-newzealand","tag-nz","tag-physics","tag-science"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts\/587851","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/comments?post=587851"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts\/587851\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/media\/587852"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/media?parent=587851"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/categories?post=587851"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/tags?post=587851"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}