Space & Physics: Planet-Jostling Primordial Black Holes Could Explain Dark Matter

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September 26 — This week, our top story asks whether the universe's mysterious dark matter might be made up of minuscule black holes—and explains how, if so, we should see one passing through the solar system and subtly jostling the planets every decade or so. Elsewhere, we have coverage of quantum entanglement in quarks, Earth's latest mini moon, the prospect of nuking planet-threatening asteroids, and more. Enjoy! Additionally, we have a correction for last week's newsletter. In the section entitled "What's Standing in the Way of a U.S. Lunar Return?" the text should have noted that NASA's Apollo program sent nine crews of astronauts to the moon and back, not 10. --Lee Billings, Senior Editor, Space and Physics

Dark Matter Could Be Hiding Out as Atom-Sized Black Holes The universe's hidden mass may be made of black holes, which could wobble the planets of the solar system when they pass by

A Wild Way to Look for Dark Matter For decades, scientists have been speculating about a tantalizing dark horse in the race to understand the nature of dark matter, the invisible substance that binds together galaxies and larger cosmic structures. Rather than being made of undiscovered subatomic particles or arising from oversights in theorists' equations, dark matter could be a bizarre class of black holes that may have arisen shortly after the big bang. Such "primordial" black holes could be about as heavy as an asteroid yet as small as an atom. And according to a new study, if they are indeed dark matter, they should be so prevalent as to pass through our solar system about once per decade, causing subtle-but-detectable shifts in the motions of some planets, moons and asteroids. Is this wild idea plausible? Remarkably so. Is it probable? That's a thornier question. But as scientists' increasingly thorough searches leave whatever's behind dark matter with ever-fewer ways to hide, the possibilities that remain must be carefully considered—no matter how unlikely they may seem. --Lee Billings

In Other News

'Spooky Action at a Distance' Observed in Quarks for the First Time Physicists report the first observations of quantum entanglement in top and anti-top quarks, the heaviest known fundamental particles and their antimatter counterparts, inside the Large Hadron Collider Dan Garisto; Nature magazine

Scientists Nuke an Asteroid in a Lab Mock-Up Experiment shows that a nuclear explosion could save the planet from a deadly asteroid impact Jonathan O'Callaghan; Nature magazine

Earth Is Getting a New Mini Moon A small asteroid, 2024 PT5, will spend the next two months alongside our planet as a mini moon before swooping back to deep space Lee Billings

Why Do So Many Tiny Asteroids Have Moons? Scientists are putting a new spin on the creation of binary asteroids Phil Plait

What Really Happened at the Pentagon's Once-Hidden UFO Office? An office in the Pentagon investigated UFOs—and the paranormal—over a decade ago, segueing into a long saga leading to Congressional hearings and breathless news stories today. But the real story looks more like former defense officials pushing their personal mythology, rather than any cover-up of aliens Luis Cayetano Simmari, expert writer; Vicente-Juan Ballester Olmos, expert writer

As Earth's Climate Unravels, More Scientists Are Ready to Test Geoengineering More and more climate scientists are supporting experiments to cool Earth by altering the stratosphere or the ocean Mark Fischetti

This Elegant Math Problem Helps You Find the Best Choice for Hiring, House Hunting and Even Love Math's "best-choice problem" could help humans become better decision-makers, at everything from choosing the best job candidate to finding a romantic partner Jack Murtagh

From the Archive

Is Dark Matter Made of Black Holes? A hidden population of black holes born less than one second after the big bang could solve the mystery of dark matter Juan García-Bellido; Sébastien Clesse

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