Mercury

In the 15th century, Mercury was first spotted by Johannes Hevelius. Mercury is made up of a small lump of rock, half as big as our moon. There are no clouds on Mercury to protect it from the Sun or to keep it cool at night. Because it has no atmosphere, during the day its temperature is 420° C and at night it drops to a very chilly - 180° C. Astronomers had a very detailed look at Mercury in 1974, with Mariner 10. Mercury is the first planet away from the Sun. It is one of the four inner planets. In Earth time, it takes it 0.24 years for it to orbit the Sun. It takes 58days 15hrs 36mins to rotate on its own axis. It is the fastest moving planet in the solar system and it is 36,000,000 miles from the Sun.

Martin Dicks and Andy Loades