Near-Earth object Near-Earth object A near-Earth object (NEO) is any small Solar System body whose orbit brings it to proximity with Earth. By convention, a Solar System body is a NEO if its closest approach to the Sun (perihelion) is less than 1.3 astronomical units (AU). If a NEO's orbit crosses the Earth's and the object is larger than across, it is considered a potentially hazardous object (PHO). Most known PHOs and NEOs are asteroids, but a small fraction are comets. There are over 19,000 known near-Earth asteroids (NEAs), over a hundred short-period near-Earth comets (NECs), and a number of solar-orbiting spacecraft
Earth's orbit Earth's orbit All celestial bodies in the Solar System, including planets such as our own, orbit around the Solar System's centre of mass. The sun makes up 99.76% of this mass which is why the centre of mass is extremely close to the sun. Earth's orbit is the trajectory along which Earth travels around the Sun. The average distance between the Earth and the Sun is 149.60 million km (92.96 million mi), and one complete orbit takes days (1 sidereal year), during which time Earth has traveled 940 million km (584 million mi). Earth's orbit has an eccentricity of 0.0167.