Asteroids, meteorites and comets
Eight planets, several dwarf planets and a large number of small bodies such as asteroids and meteoroids orbit our Sun. Our Solar System harbours asteroid and meteoroid groups at all possible heliocentric distances (measured from the Sun). The most prominent population is the main asteroid belt between Mars and Jupiter. This collection of hundreds of thousands of asteroids could possibly be the components of a planet that failed during its construction.
Asteroids: An asteroid is a small celestial body with a diameter ranging from a few metres to several hundred kilometres that moves in an orbit around the Sun. Its low mass means that its gravity is also too low for it to assume a spherical shape. It therefore assumes an arbitrary shape.
Meteoroids: A meteoroid is a body that also orbits the Sun. It is smaller than an asteroid, with a magnitude in the order of millimetres to metres. However, there is no fixed boundary to the larger asteroids.
Meteors / Shooting stars: A meteor is a meteoroid that enters the Earth's atmosphere and produces a light phenomenon known as a shooting star. A meteor burns up completely in the atmosphere.
Meteorites: A meteorite is a meteoroid that enters the Earth's atmosphere, passes through it and only partially burns up before hitting the Earth.
Comets/Comet nuclei: A comet nucleus is a celestial body with a diameter usually less than 40 kilometres that outgasses near the Sun, producing a luminous tail. This phenomenon is known as a comet. Comet nuclei originate in the outer regions of the Solar System. They may be in stable orbits around the Sun where they return at periodic intervals, or they may only come close to the Sun once in their lifetime.