1. The English name for the planet comes from the Romans, who named it after the Roman god 'Mercury'.
2. Mercury is denser than any other planet in the solar system, except Earth.
3. Before 4th century BC, Greek astronomers believed Mercury to be two separate objects: one visible only at sunrise, which they called 'Apollo' and the other visible only at sunset, which they called 'Hermes'.
4. Mercury can only be seen early morning and in twilight.
5. Mercury has no atmosphere and no known satellites.
6. Mercury has a large iron core, which generates a magnetic field about 1% as strong as that of the Earth.
7. Mercury is the only planet whose orbit is coplanar with its equator.
8. The first visit to Mercury was made by the Mariner 10 spacecraft, in 1974.
9. Despite being the planet closest to the Sun, Mercury is not the warmest. Rather, Venus is warmer and Mercury can be one of the coldest planets in the Solar System.
10. If you were to stand on Mercury, Sun would appear two and a half times bigger than what it looks from Earth.
