An asteroid is very similar to a comet - it is a large rock that orbits the sun. Comets have a tail, while asteroids do not.

Smaller rocks, from the size of a grain of sand to a large bounder are called meteoroids. When they enter the Earth's atmosphere, they are called meteors. If they hit the ground, they are called meteorites. The photo is of a meteorite.

Comets are lumps of rock and ice that travel around the sun. They are usually a few kilometers across. When they get close to the sun, they develop a tail. The tail of the comet always points away from the sun.

Jupiter is the largest planet in our solar system. It is the fifth planet from the sun. It has four planet-sized moons and many smaller moons; 63 in total.

Jupiter is 778,412,020km from the Sun.

Its radius is 71,492km.

Mercury is a small, rocky planet. It is the closest planet to the sun. During the day it can reach 467 degrees Celsius on the surface of Mercury, but at night it can drop to -170 degrees Celsius.

Mercury is 57,909,175km from the Sun.
Its radius is 2439.7 km.

Neptune is the eighth planet from the sun. It was discovered by mathematical predictions, not with a telescope. Neptune has 13 moons; the largest is called Triton.

Neptune is 4,498,252,900km from the Sun.
Its radius is 24,764km.