Deutsch: Asteroid / Español: Asteroide / Português: Asteroide / Français: Astéroïde / Italiano: Asteroide /
An asteroid is a minor planet of the inner Solar System. Sizes and shapes of asteroids vary significantly, ranging from 1-meter rocks to a dwarf planet almost 1000 km in diameter; they are rocky, metallic or icy bodies with no atmosphere.
In the aerospace context, an asteroid is a small, rocky or metallic body that orbits around the sun, generally in the inner solar system, between the orbits of Mars and Jupiter. They are thought to be remnants from the formation of the solar system, and are often considered "minor planets" or "planetoids."
Asteroids come in a variety of sizes and compositions, from a few meters to several hundred kilometers across. Some asteroids are composed mainly of rock and metal, while others are made mostly of ice. Most asteroids are irregularly shaped, and many have irregular orbits that bring them close to the Earth's orbit.
Examples of asteroids include:
- Ceres, is the largest asteroid, and a dwarf planet, in the asteroid belt.
- Vesta, the second-most-massive asteroid and is considered a protoplanet.
- Eros, is an asteroid of the Amor group, it was visited by the NEAR Shoemaker spacecraft.
- Bennu, which is a carbon-rich asteroid, was visited by NASA's OSIRIS-REx spacecraft in 2018 and is expected to return a sample to Earth in 2023
- Ryugu, is a small near-Earth asteroid, it was visited by JAXA's Hayabusa 2 spacecraft.
Asteroids are of interest to scientists and the aerospace industry.