Planetary Defense

Planetary Defense is a scientific and technical site that provides information on the protection of planet Earth from impact by asteroids, comets, and meteoroids. It is sponsored by the Planetary Society.

The goal of Planetary Defense is to provide accurate and timely information about the threat of impact by Near-Earth Objects (NEOs), what can be done to prevent or mitigate such impacts, and how to prepare for them.

Currently, there are no known NEOs that pose an imminent threat to Earth, but it is important to remain vigilant and continue monitoring the skies for potential threats. There are a number of ways to detect and track NEOs, including ground-based telescopes, space-based telescopes, and radar.

There are also a number of ways to deflect or destroy an NEO before it hits Earth. These include kinetic impactors (e.g., hitting the object with a spacecraft), nuclear explosives, gravity tractors (using the gravity of a spacecraft to tug on an NEO), and solar sails (reflecting sunlight off of a large mirror).

A comprehensive effort involving all of these methods will be required to effectively protect Earth from future impacts. The first step is identifying potential threats early enough so that we can take action to avoid them.