End Times

How to Defend the Planet

A six-mile-wide asteroid ended the dinosaurs, and the same could happen to us one day. But NASA is at work on ways to keep us safe.

An illustration of an asteroid in space. Image credit: NASA / JPL / Caltech.

Asteroids, supervolcanoes, nuclear war, climate change, engineered viruses, artificial intelligence, and even aliens — the end may be closer than you think. For the next two weeks, OneZero will be featuring essays drawn from editor Bryan Walsh’s forthcoming book End Times: A Brief Guide to the End of the World, which hits shelves on August 27 and is available for pre-order now, as well as pieces by other experts in the burgeoning field of existential risk. But we’re not helpless. It’s up to us to postpone the apocalypse.

News that a “city-killer”-scale asteroid came within 45,000 miles of the Earth on July 25 — and that astronomers didn’t see it until the object had already passed by the planet — is a timely reminder that the universe can be a hostile place. But unlike a number of other natural existential risks, we have the ability to protect ourselves from such near-Earth objects (NEOs) — at least, theoretically.

The way to stop an NEO is to deflect it, though that word is deceptive. Rather than trying to knock an asteroid to the side, we would try to either slow down or accelerate the…