Extraterrestrial

New York Times Bestseller | Wall Street Journal Bestseller | Publishers Weekly Bestseller | Publishers Marketplace 2020 Buzz Book  | Amazon Best Book of the Year | Longlisted for the 2022 PEN/E.O. Wilson Literary Science Writing Award

“Provocative and thrilling ... Loeb asks us to think big and to expect the unexpected.”

—Alan Lightman, New York Times bestselling author of Einstein’s Dreams and Searching for Stars on an Island in Maine

Harvard’s top astronomer lays out his controversial theory that our solar system was recently visited by advanced alien technology from a distant star.

In late 2017, scientists at a Hawaiian observatory glimpsed an object soaring through our inner solar system, moving so quickly that it could only have come from another star. Avi Loeb, Harvard’s top astronomer, showed it was not an asteroid; it was moving too fast along a strange orbit, and left no trail of gas or debris in its wake. There was only one conceivable explanation: the object was a piece of advanced technology created by a distant alien civilization.

In Extraterrestrial, Loeb takes readers inside the thrilling story of the first interstellar visitor to be spotted in our solar system. He outlines his controversial theory and its profound implications: for science, for religion, and for the future of our species and our planet. A mind-bending journey through the furthest reaches of science, space-time, and the human imagination, Extraterrestrial challenges readers to aim for the stars—and to think critically about what’s out there, no matter how strange it seems.

This riveting, evidence-based argument explores the profound questions raised by our first interstellar visitor:
The 'Oumuamua Anomalies: Why the object’s extreme shape, strange orbit, and lack of a cometary tail defy every natural explanation—except one.The Lightsail Hypothesis: A detailed look at the simplest explanation for ‘Oumuamua’s acceleration: that it was a piece of advanced technology, a solar sail designed by an intelligent civilization.Astro-Archaeology: A call for a new field of science dedicated to searching for technological relics and debris left behind by other civilizations, living or dead.The Great Filter: What the silence in the cosmos—and this first tantalizing clue—reveals about the fate of technological civilizations, including our own.