![The Earth - Teachoo.png](https://d1avenlh0i1xmr.cloudfront.net/8e4d703b-0abe-403b-b46e-c9922551b639/the-earth---teachoo.png)
- Earth : the third planet from the sun, the fifth largest in the solar system, the largest among the inner planets.
- Earth is unique and home to life because of:
- Best location with reference to the sun, not too hot or cold.
- Favourable environmental conditions for the origin and survival of life forms.
- Rotation on its axis keeps the temperature difference between day and night tolerable.
- Favorable temperature for the existence of life, water can be in three forms: ice, water and vapor.
- Adequate water in oceans is ideal for the origin and evolution of life.
- The presence of the atmosphere protects from harmful ultraviolet radiations and has oxygen-rich air for living beings.
- The symbol of the earth is a circle with two perpendicular lines which represent the intersection of the equator and the Prime Merdian .
- Earth looks blue from space due to water, called the watery planet or the blue planet.
- Earth was thought to be flat in ancient times, Aristotle and Copernicus declared it spherical.
- Earth is not a perfect sphere, slightly flattened at the poles and bulging at the equator. That is why, its shape is described as a Geoid.
- The light of the sun takes about eight minutes to reach the Earth.