Asteroids

Asteroids

Asteroids are made up of rock and iron like the four planets closest to our Sun. Juno, the third asteroid ever discovered, September 1, 1804, was first spotted by astronomers early in the 19th century. It orbits the Sun with thousands of other bits of space rock in the main asteroid belt between Mars and Jupiter. One of the largest asteroids, at a size of 150 miles across, Juno essentially is a leftover building block of the solar system. Learn more about asteroids.