15 Facts About Mercury (Planet)
Mercury is one of the most fascinating planets in our Solar system.
As you can see the planet without a telescope (with difficulty), people have known about Mercury's existence for thousands of years, but it wasn't until the 20th century that we really got to understand what the planet was really like.
Closer to the Sun than any other planet in our Solar System and also the smallest of the eight planets, Mercury is rocky and without an atmosphere.
I hope that you enjoy reading my 15 facts about Mercury and find them interesting and fun!
1. Mercury is the closest planet to the Sun, the distance between them being 35,980,000 miles (57,910,000 km).
2. Mercury speeds through space at around 30 miles per second (50 km per second), faster than any other planet in the Solar System.
3. People have known about the planet for thousands of years. The ancient Greeks and Romans made written observations, which we still have.
4. Mercury is named after a god from Roman mythology, who served as a super-fast messenger for the other gods, and is often pictured wearing winged sandals. The Greek version of the god was called Hermes. As well as being a messenger of the gods, he is also the god of financial profit, business, eloquence (and therefore poetry), all forms of communication, travelers, luck, trickery and thieves; plus he serves as a guide to souls in the underworld.
5. The surface of the planet is rather like the Moon. It is barren and rocky and covered with craters.
6. The planet has lots of craters because it has virtually no atmosphere to protect it from meteoroids and asteroids. (The only atmosphere is very thin and unstable).
7. The lack of atmosphere also means that the planet goes through big temperature changes. During the day, because Mercury is close to the sun, it heats up to around 750 degrees Fahrenheit - but at nighttime, without an atmosphere to stop the heat escaping, the temperature drops to -300 degrees Fahrenheit. That's a temperature difference of over 1000 degrees!
8. Because there is virtually no atmosphere, the planet has no winds, or weather systems.
9. Mercury has a very eccentric orbit. At its closest, it is just 29 million miles (46 million km) from the Sun, but at its farthest, it is 43 million miles (70 million km).
10. Because the planet is much smaller than the Earth, it has weaker gravity. Someone weighing 70 pounds (32 kg) on Earth, would weigh only about 27 pounds (12 kg) on Mercury. (It is the weak gravity that stops an atmosphere from forming around the planet).
11. The planet has an iron core, like the Earth. Mercury's core may be molten, however, whereas the Earth's has largely cooled. It is also thought that Mercury’s core makes up 42% of its volume, while the Earth’s core makes up just 17%.
12. Because Mercury is much closer to the Sun than the Earth is, the Sun looks more than twice as large in the sky.
13. Mercury rotates on its axis very slowly. It takes 59 Earth days for the planet to complete a single rotation.
14. The latest space probe to visit the planet is called MESSENGER. Its mission is expected to be completed in 2013.
15. A joint mission between the European Space Agency and Japan is planning to launch a spacecraft bus with two probes called BepiColombo in August 2015, expected to enter orbit around Mercury in January 2022. Once in position, BepiColombo will gather data relating to the planet for around one year, possibly extended to two years.
Solar System Facts
- The Solar System is around 4.6 billion years old.
- The Sun is by far the most significant body in it, containing over 99% of the system’s mass.
- There are eight planets in the system, four inner and four outer.
- The inner planets are smaller and rockier and consist of Mercury, Venus, Earth and Mars.
- The outer planets are larger and gassier and consist of Jupiter, Saturn, Uranus, and Neptune.
- Other objects that exist in the system include dwarf planets, moons, asteroids, the asteroid belt, comets and the Kuiper belt.
- The outermost shell of icy objects is known as the Oort Cloud (named after the astronomer Jan Oort). There are an estimated 2 trillion objects in the Oort Cloud. The objects are thought to be leftovers from the formation of the Sun and planets.
© 2012 Paul Goodman