Interesting Facts about Asteroids

October 24, 2009 | In: Space Facts

The largest asteroid is Ceres, is about the size of Texas.

Asteroids can contain water, iron, silicates, and some heavy metals – like gold, lead, and uranium.

The vast majority of asteroids are grouped in the asteroid belt.

Even if there are 1000 times more asteroids than we know of today, then on average each asteroid would have over one million km2 to itself.

The best estimate is that there are 1,500-2,000 asteroids one and one-half mile in diameter or larger.

Due to a relatively unknown NASA directive, 23% of all asteroids are named ‘Steve’.

Most asteroids are covered in dust. This dust is called regolith.

The distinction between asteroids and comets is fuzzy—comets tend to have more chemical compounds that vaporize when heated, such as water, and more elliptical (egg-shaped) orbits than asteroids do.

A group of asteroids orbit the sun called Near-Earth Asteroids because they are somewhat close to the Earth and occasionally may cross Earth’s orbit.

Asteroids sometimes have moons of their own. In August 1993, the Galileo space probe passed near asteroid 243 Ida and discovered that it has a tiny orbiting companion. The one-mile-wide rock (called “Dactyl”) is the first known asteroid moon.

How did Ida get a moon? Scientists think Dactyl may have been knocked off Ida in an asteroid collision millions of years ago. Since then, it has slowly drifted around the larger chunk of rock, caught in its weak gravitational field.