asteroid

/ˌæstəˈrɔɪd/

/ˈæstərɔɪd/

Other forms: asteroids

An asteroid is a large, irregularly shaped object in space that orbits our Sun. If one of these giant rocks ends up on a collision course with Earth, we are in for big trouble.

An asteroid is like a comet. However, while comets are mostly made of ice, asteroids are made up of rock or even metal. This makes them dangerous because they can cause a lot of damage if they collide with a planet. The craters on the Moon were formed by asteroids and some think it was an asteroid that wiped out the dinosaurs. Around a million asteroids are located between Mars and Jupiter in an area called the “asteroid belt.”

Definitions of asteroid

1. noun

   any of numerous small celestial bodies composed of rock and metal that move around the sun (mainly between the orbits of Mars and Jupiter)
   examples:

   Apollo asteroid

   an asteroid whose orbit crosses the Earth's orbit

   Ceres

   the largest asteroid and the first discovered

   Pallas

   a large asteroid; the second asteroid to be discovered

   Vesta

   the brightest asteroid but the fourth to be discovered

   types:

   Chiron

   an asteroid discovered in 1977; it is unique in having an orbit lying mainly between the orbits of Saturn and Uranus

   type of:

   minor planet, planetoid

   any of numerous small celestial bodies that move around the sun
2. adjective

   shaped like a star
   synonyms: star-shaped

   angular, angulate

   having angles or an angular shape