Space & Physics: Will this "city killer" asteroid strike Earth in 2032?

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February 20 — This week, scientists are eyeing 2024 YR4, a sizable asteroid with a chance of striking Earth in 2032. Also, a purported quantum breakthrough from Microsoft, the physical (and fiscal) folly of the Trump administration's "Iron Dome for America" missile-defense plan, a first-of-its-kind simulation of universe-destroying "cosmic bubbles," and much more. Enjoy! —Lee Billings, Senior Editor, Space and Physics

'City Killer' Asteroid's Earth Impact Risk Rises to Highest Ever Recorded Asteroid 2024 YR4's risk of hitting Earth is shifting with new data, astronomers say

Will it or won't it? That's the question planetary-defense experts keep asking themselves about a roughly football field-sized asteroid, 2024 YR4, that appears to have a concerning chance of hitting Earth in late 2032. If this errant space rock were to strike somewhere on our world—its predicted "risk corridor" includes densely populated places like Bogotá, Lagos, and Mumbai—the energy released could be akin to that of a detonating nuclear bomb. Which is why asteroids of this size are sometimes called "city killers" by the scientists who study them. Ever since 2024 YR4's potential collision course was announced in January, astronomers have been working overtime to precisely determine its orbit, and thus its true likelihood of giving some of us a very bad day in 2032. The estimated impact probability has fluctuated over time, and earlier this week rose to a record-setting 3.1 percent before falling again hours later to 1.5 percent as new data rolled in. That considerable drop likely means the odds of an impact will continue to plummet, but for the time being scientists are staying wary, still watching the skies to ensure that we have the best threat assessment possible for this worrisome space rock. —Lee Billings

Top Stories

Microsoft Claims Quantum-Computing Breakthrough—but Some Physicists Are Skeptical With its 'topological' quantum computers, Microsoft aims to reach useful scales faster than competing technologies Davide Castelvecchi; Nature magazine

Trump's 'Iron Dome' Space Weapons Plan Ignores Physics and Fiscal Reality Proposed U.S. space defenses against hypersonic nuclear missiles are unnecessary, impractical and would trigger a dangerous new arms race Dan Vergano, staff journalist

Quantum Simulation Shows How Universe-Destroying 'Bubbles' Could Grow Physicists are finding new ways to model false vacuum decay, a terrifying, albeit remote, cosmic endgame Dan Garisto

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From the Archive

Don't Panic: The Valentine's Day 2046 Asteroid Will Not Hit Earth. Here's Why How I learned to stop worrying and love the next Earth-threatening asteroid Phil Plait

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