Could the hunt for the universe’s missing matter be the biggest wild goose chase in scientific history? ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏
September 15, 2026—The search for dark matter is dragging on—what if we never find it? Plus, we speculate which million-dollar math problem will be solved next, and we examine data behind school lunches.
—Andrea Gawrylewski,
Chief Newsletter Editor
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Yaroslav Kushta/Getty Images
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Last week an OpenAI model reportedly solved one of the million-dollar math problems. Which one will AI likely solve next? | 8 min read
Join the discussion: Which Millennium Prize Problem do you think will be solved next? And will it be humans or AI that claim the prize? Share your thoughts here.
How much do universal lunch programs affect academic performance? Scientific American looked at the data. | 6 min read
It's official: the U.S. has weapons in space. A high-ranking official announced yesterday that the U.S. military has deployed weapons into orbit to counter threats from Russia and China. | 3 min read
How do you think the number sequence 1, 2, 4, 8, 16... continues? Most people would guess 32. But the answer is not what you think and is related to Moser’s circle problem in math. | 6 min read
We sat down with sociologist Sherry Turkle to discuss her upcoming book Artificial Intimacy: Who We Become When We Talk to Machines and how the advent of artificial intimacy is warping actual human behavior. | 27 min podcast
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Photomultiplier tubes in the XENONnT experiment at Italy’s Gran Sasso National Laboratory search for signs of dark matter particles interacting with liquid xenon. XENON Collaboration
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What is Dark Matter?
Today we launched our October issue, which deals in impossible questions—a survey of scientific quandaries that may never get definitive answers. At the top of the list is dark matter.
Last month, a flurry erupted among physicists at the reported observation of a single unexplained collision in one of dozens of detectors. Many wondered (hoped?) that scientists had finally observed dark matter, the elusive substance that makes up five sixths of the universe’s matter but has yet to be identified. But, as our senior reporter, and former dark matter researcher, Joseph Howlett writes, if the 30-year search is any guide, this latest discovery likely won’t be the answer.
The backstory: In the 1970s, astronomer Vera C. Rubin meticulously cataloged the movement of stars within as many galaxies in the sky as she could. What she found was that the stars near the edge of every galaxy in the observable universe are moving way too fast. Like a racecar hitting a corner with too much speed, these stars should be sent flying off their orbital racetracks and into the void. The gravity of everything we can see within their galaxies simply isn’t enough to hold them in. But that’s not what happens. So there must be a lot of invisible matter in these galaxies creating the gravity to hold stars in—in fact, the gravity of these galaxies is about five times stronger than their visible stars and dust would suggest. But what the heck is causing the pull?
The candidates: A strong contender for dark matter, for decades, was weakly interacting massive particles, or WIMPs. These as yet undiscovered particles would have to be some 50 times the mass of a proton to explain the contradictions in Rubin’s data. But so far, the hunt for WIMPs has come up short. Other options: axions (ultra-light elementary particles) or lower-mass WIMPs or primordial black holes (objects dating to the big bang that would have a mass maybe a bit less than the moon’s packed into a microscopic ball).
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Joseph Howlett (center) and other scientists huddle around a computer screen far below the Gran Sasso mountain, in a large WIMP-searching lab, watching the results of a critical equipment test. Masaki Yamashita
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The vibe: But what if dark matter is none of these things, asks Howlett? “What if it is not connected to our world through any force besides gravity? In that case, no conceivable technology could sense a single particle of the stuff,” he writes. “Dark matter would be like a shadow realm, superimposed on but disconnected from our own except through its collective tug, its denizens utterly unknowable to us.”
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The search for dark matter is certainly taking my colleague Joe Howlett to a ... dark place. He writes in his feature this month that perhaps this enduring cosmic mystery can be explained by something that philosophers have known all along, that "science will never give us a complete picture of reality." The 18th century German philosopher Immanuel Kant had a similar radical idea: we humans can never step outside the machinery of our own cognition to see reality as it truly is. Even if that is fundamentally true, and even if all scientists come to believe it, I still trust that discovery and observation will carry on and lead us to remarkable new insights.
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—Andrea Gawrylewski,
Chief Newsletter Editor
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