The Earth and its moon share a special relationship. The only natural satellite of Earth, the Moon produces the tides and lunar eclipses. It has also inspired thousands of years of poetry, myths and stories.
As our home planet, the Earth is the only known celestial body to support life. It has done so for at least 3.5 billion years.
Here are 10 facts about the Earth and the Moon.
1. The Moon is getting further away
Each year, the moon is about 4cm further away from the Earth.
2. The Moon is only the 5th largest natural satellite in the Solar System
Ganymede, Titan, Callisto and Io are larger, but the Moon is the largest when compared to the planets they orbit.
3. The Moon’s rotation is synchronised
That means that it rotates in the same number of days that it takes it to complete one orbit. That is the reason we always see the same side of the Moon. The picture above shows the far side of the Moon.
4. The footprints and Lunar Rover tyre tracks will remain as clear as the day they were made for millions of years
There is no atmosphere on the moon and therefore no weathering. Given time, they may be covered by particles of dust landing on the moon from space.
5. The Moon is one quarter the diameter of the Earth
It is believed that the Moon was formed when a huge asteroid hit the Earth in its very earliest days of formation. Because of its small size, on the Moon you would weigh only one sixth of what you weigh on Earth.
6. The Earth is the only planet with liquid water on its surface
Without liquid water, life as we know it could not exist. The first life may have begun around hydrothermal vents like the one shown above.
7. The Earth is about 93 million miles (150 million kilometres) from the Sun
That is 8 light minutes away. To drive to the sun at motorway speed would take you over 150 years!
8. The Earth is the only planet in our Solar System not to be named after a Greek or Roman god
9. The rotational speed of the Earth is slowing down
The effect is very small and is caused by tidal friction. The rotational momentum of the Earth is gradually being transferred to the Moon, which is therefore increasing in speed. This will stop when the length of the day is the same as the length of the month.
10. The magnetic field of the Earth protects us from the harmful effects of the Solar Wind
The magnetic field creates the Van Allen belts, regions or space near the Earth that trap the particles of the Solar wind.