At the end of 2003, there were 2600 known Near Earth Asteroids (NEAs), and of these 691 are brighter than absolute magnitude, which is taken to correspond to a diameter of 1 kilometer or more. Of these, 131 are classed as PHAs (potentially hazardous asteroids) larger than 1 km. This site describes the potentially devastating effects of a collision between Earth and a large meteor or asteroid. It also describes the Spaceguard Survey, which is an initiative to locate and catalog as many potentially hazardous NEAs as possible. Other parts of the site include: a news archive, bibliography, catalog of near earth objects, image gallery, and links to related sites.

No specific technical requirements, just a browser required

No cost

NASA materials may not be used to state or imply the endorsement by NASA or by any NASA employee of a commercial product, service or activity, or used in any other manner that might mislead. NASA should be acknowledged as the source of its material.It is unlawful to falsely claim copyright or other rights in NASA material. NASA shall in no way be liable for any costs, expenses, claims or demands arising out of use of NASA's cassettes and photographs by a recipient or a recipient's distributees. NASA personnel are not authorized to sign indemnity or hold harmless statements, releases from copyright infringement, or documents granting exclusive use rights.

Contributor: David Morrison
NASA Ames Space Science Division