An asteroid is a low gravity body. It 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.
An asteroid is Not a comet. Nor is it a meteorite.
Comets are small icy dirtballs that orbit the Sun; comets are made of
ice and dust while asteroids are made of rock. A meteor is a space
rock—or meteoroid—that enters Earth's atmosphere, as it – burns up upon
entering Earth's atmosphere, it creating a streak of light in the sky
(often called "shooting stars"). The first discovered asteroid, Ceres,
was originally considered a new planet. It was followed by the discovery
of other similar bodies, which with the equipment of the time appeared
to be points of light like stars, showing little or no planetary disc,
though readily distinguishable from stars due to their apparent motions.
This prompted the astronomer Sir William Herschel to propose the term
asteroid, coined in Greek as ἀστεροειδής, or asteroeidēs, meaning
'star-like, star-shaped', and derived from the Ancient Greek ἀστήρ astēr
'star, planet'.
I am an aerospace engineering PhD candidate. I work on space probes which aim to land on asteroids. I am also a pilot. In fact I am a private pilot.