near-Earth object

Near-Earth objects (NEOs) are astronomical bodies, such as asteroids and comets, whose orbits around the Sun bring them close to Earth. These objects pose a potential hazard due to the possibility of collision.1

NEOs are categorized based on their orbits:
* Mars crossers: Cross Mars's orbit, with perihelion distances greater than 1.3 AU.
* Amors: Have perihelion distances greater than Earth's aphelion distance (1.017 AU) but no more than 1.3 AU. They do not currently cross Earth's orbit.
* Apollo asteroids: Have mean distances from the Sun greater than or equal to 1 AU and perihelion distances less than or equal to Earth's aphelion distance.
* Atens: Have mean distances from the Sun less than 1 AU and aphelion distances greater than or equal to Earth's perihelion distance (0.983 AU).
* Atiras: Have orbits entirely inside Earth's orbit.

The danger from an impact depends on the object's mass and velocity, determining the kinetic energy released. While small objects burn up in the atmosphere, larger ones can cause significant devastation, including global climatic changes and mass extinctions. Scientists actively conduct search programs to detect NEOs and assess their potential threat.1