Earth,+Sun+and+Moon

=Earth, Sun and Moon=



**The Sun**
The sun is a star and it is responsible for all activity in the solar system – it gives out immense amounts of light and heat. It is roughly spherical in shape and is many times bigger than the earth. In fact, the sun makes up 98% of all the material in the solar system, and due to its vast size, it has more gravity than anything else in the solar system, which is why all planets, satellites and other materials orbit it.

**The Earth**
The Earth is a roughly spherical shape and like all planets it orbits the sun. A year is the time it takes to complete one orbit and on Earth this is equivalent to 365 days.

The Earth also turns on its own axis - the side of the Earth facing the sun experiences daytime. The side facing away is in darkness, and as the Earth spins, day becomes night and vice-versa. A full axial rotation takes 24 hours.

In addition, the seasons are determined by Earth’s tilt as it orbits the sun, so during winter months, the Hemisphere furthest from the sun experiences less direct sunlight and the opposite is happening in the other Hemisphere.

The Earth is the only planet in the solar system capable of sustaining complex life forms. This is due to its distance from the sun which provides optimal temperature, weather and atmospheric conditions to sustain life in an otherwise desolate solar system. Almost 7 billion human beings inhabit the planet, but humans are relatively new life forms, and the planet has sustained life for millions of years.



**The Moon**
The Moon is Earth’s only natural satellite. It is also roughly spherical though in the image above it seems to swell during its phases as light from the sun reflects off different parts of its surface.

It is the largest natural satellite of a planet in the Solar System relative to the size of its primary, having a quarter the diameter of Earth and 1⁄81 its mass. The **Giant Impact Hypothesis** is a current theory that suggests that it was formed from the matle of the Earth, during the Earth's collision with a hypothetical planet, Theia. The debris from the collision spun off and formed the moon and the Eart's graviity helld it in orbit as it formed.



It orbits the Earth once every 28 days (A Lunar Month). On Earth, we can see the Moon because it reflects light from the sun. The Moon spins on its own axis at the same rate that the earth rotates so as it moves around the earth, we see the same side at all times. The legendary 'far side of the moon' is always hidden from the Earth. The far side is battered in appearance and has more impact craters, thought to be due to the near side being protected by the Earth with the far side taking the brunt of passing comets.

The changing shape of the bright part of the moon that we see is called its phase. As the Moon makes its way around the Earth, its position in relation to the Sun and Earth changes the angle and the part we see lit from earth is changed. There are 8 named phases.



**Extra**
There are 8 planets in our solar system. They are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. The order in which they are named depends on their distance from the sun, with Mercury being the closest to the sun, and Neptune the furthest away. Pluto is no longer classified as a planet! It is a dwarf planet.

The eight planets all orbit the sun. The size of these orbits depends upon the planets’ distance from the sun. Mercury therefore has the smallest orbit and Neptune the largest.

Planets also rotate on their own axis. Each planet rotates at a different speed. In addition, all planets except Mercury and Venus are orbited themselves by satellites similar to our Moon.