A satellite is a solid heavenly body that revolves round a planet. The moon revolves round the earth, so moon is a satellite of the earth. The inner planets have few moons. Earth has one, and Mars has two tiny satellites.
Moon
The giant outer planets, however, resemble small solar systems, with many moons orbiting each planet. The largest satellite in the solar system is even bigger than Mercury and Pluto while the smallest of these moons is less than 32 kilometers across. The giant planets probably have more small moons yet to be discovered.
The satellites have no light of their own. They shine because they reflect the light of the sun.
Seen from the earth at full moon, there are bright regions and dark regions on the moon's surface. The dark regions are called seas. There are great flat places on the moon which have been given the names 'Sea of Serenity' and the 'Sea of Rains'.
The moon takes days to rotate once on its axis. The force of gravity on the moon is only one-sixth that on the earth. Astronauts from the Apollo space-crafts landed on the moon's surface and brought back rock and soil samples. Analysis of the samples revealed that these rocks are similar to basaltic rock on earth.
The far side of the moon is not visible from the earth because as its period of revolution around the earth, is equal to its period of rotation on its own axis. Photographs of the far side of the moon have been shot by space probes.
