What is a NEO?

Answer 1

A NEO is a Near Earth Object.

It is is a Solar System object whose orbit brings it into close proximity with the Earth. All NEOs have a perihelion distance < 1.3 AU . They include a few thousand Near Earth Asteroids (NEAs), near Earth comets, a number of solar orbiting spacecraft, and meteoroids large enough to be tracked in space before striking the Earth.

NEA have orbits that lie partly between 0.983 and 1.3 astronomical units away from the Sun.

Asteroid 1989 FC approached Earth on March 23, 1989. The 300 meter missed the Earth by 700,000 kilometers passing through the exact position where the Earth was only 6 hours before. If the asteroid had impacted it would have created the largest explosion in recorded history.

Asteroid 1950 DA will approach Earth on March 16, 2880, during its close approach it has been estimated as having a 1 in 300 chance of impacting with the Earth. It has a diameter of about a kilometer (.6 of a mile).

Answer 2

NEO stands for "Near-Earth Object," which refers to any asteroid or comet with an orbit that brings it close to Earth's orbit. Monitoring NEOs is important to understand potential impact threats and develop mitigation strategies in case of a potential impact event.