Get Basic knowledge about Earth

The earth one of the planets of the solar system. We all know that It is the fifth largest planet and in 3rd position in solar system.

Shape

Shape of the is likely an orange in a word.

Structure

The main layers are: 1. crust- 30-35 km in thickness (average); 2 Mantle- 2,900 km in thickness (average); 3. Outer core- 2,100 km of molten material (average); 4. Inner core- 1,370 km of solid mass (average)

Some Important Data about the Earth

Diameter	12,732.2 km
Equatorial diameter	12,756 kms
Polar diameter	12,714 kms
No. of Satellites	1 (moon)
Distance from the Sun	149,597,900 kms
Time to Orbit the Sun	365 days
Mean Distance from the sun (million km)	149.6
Equatorial Diameter (km)	12,756
Period of Revolution Round the Sun or Sideral Rotation	365 days 5 hrs, 48 mts, 45.51 sec.
Period of Rotation on Own Axis or Axis Rotation	23 hrs 56 mts. 4.09 sec.
Mean Temp, of Surface	+22oC
Other Details	Most dense
Facts	Uniquely moderate temperature and the presence of oxygen and copious water maker Earth the only planet in the solar system to support life.

Composition

The earth is mane up of more than 100 different elements. The following 8 elements constitute the important ones:

Oxygen	46.5%	Sodium	2.85%
Silicon	27.72%	Potassium	2.62%
Aluminum	8.13%	Magnesium	2.09%
Iron	5.01%	Other elements	1.41%
Calcium	3.63%

Earth’s Movements

The earth has two types of movements, namely, rotation or daily motion and  revolution or annual motion.

Rotation: The earth spins on its own imaginary axis from west to east once in 24 h (in precisely 23 h 56 min and 40.91 s). it is also called diurnal or daily motion. The axis is an imaginary line which runs from north to south and passes through the centre of the earth.

Effect of Rotation:

(i) Occurrence of day and night
(ii) The position of a place on earth can be fixed

(iii) Change in the direction of wind and ocean currents.