Solar System
The Moon
Planet Earth
Our home planet. The Moon as seen through a 0.9 metre telescope.
Image copyright NASA
Image copyright T.A.Rector/I.P.Dell'Antonio/NOAO/AURA/NSF
Planet Earth is a marvelous glowing jewel of the Solar System and it is the largest rocky planet. More importantly it is the only planet with life and is akin to being an oasis in the galactic desert. The reason it supports life is because it has an atmosphere that contains oxygen and also because the surface is 70% water. The other factor is that it is the 'right' distance from the Sun and is situated in the Goldilocks Zone.

The atmosphere of Earth is 78% nitrogen, 21% oxygen and 1% other gases. It also has an ozone layer that protects the surface from ultraviolet radiation.

One unique aspect of planet Earth is that it has seasons. The cause of the seasons is that Earth is tilted at 23.3 degrees on its axis. Earth's sky is blue because the atmosphere is more efficient at the scattering of blue light than any other.

Earth has one moon, which is vital to the existence of life on Earth. It causes tides and it also smoothes out a wobble in the Earth's rotation thus stabilising the climate.


Name: Earth

Distance from Sun: 92,955,820 miles

Diameter: 7926 miles

Length of Day: 24 hours

Length of Year: 365.24 days

Number of moons: 1


The Moon in stark contrast to Earth is a lifeless dusty planetoid that has many craters, mountains and flat dark areas known as maria. The craters are easily visible as opposed to the relative few on Earth.

The reason for Earth's craters not being easily visible is because they have been eroded by wind. Also the same side of the Moon faces Earth and the far side was first photographed in 1959 by a Russian probe called Luna 3.

  White Mountain waterfall   Cuban Sunset
White Mountain waterfall in America.
Image Copyright P. Greenspun
Sunset and moon over Cuba.
Image Copyright D. Heller