Earth
sun in the sky
The earth is the nearest planet to the sun and the fifth largest planet in the solar system. In the solar system it is located between Venus and mars. It is a unique planet. It is a bit pear -shaped rather than true sphere.
1) Dimensions of the earth: The earth has on equatorial diameter of 12,756 kilometers and a polar diameter of 12,714 kilometers. It is at a distance of 14, 95, 97,900 kilometers from the sun. It orbits around the sun at a speed of 1, 07,220 kilometers per hour. The earth contains 70.92% of water and 29.08% of land.
2) Earth Axis: Earth’s axis is on imaginary line which runs right across and passes through the center of the earth. The earth spins around its axis which always remains inclined at on angle of 66 ½ degree to the plane of earth’s orbit.
3) Earth’s motions: The earth has two motions namely rotation and revolution.
4) Rotation: the earth moves around its axis from west to east. This movement is called Rotation. It takes 23 hours, 56 minutes and 4. 091 seconds to complete one rotation. Days and nights are caused due to the earth’s rotation.
5) Revolution: The earth also moves around the sun while moving around its own axis. This movement is called Revolution. It takes 365 days, 5 hours, 48 minutes and 45.52 seconds to complete one revolution. Difference in the duration of days and nights and seconds occur due to the revolution of the earth.
6) Orbit: Orbit is the elliptical path of earth’s revolution around the sun.
7) Perihelion: When the earth is nearest to the sun it is called perihelion. The earth reaches its perihelion in the beginning of journey.
8) Aphelion: When the earth is farthest from the sun it is called Aphelion. The earth reaches its aphelion in the ending of June.
9) Eclipse: The earth revolves around the sun and the moon revolves around the earth. While they revolve, at times, it happens that they come in a straight line. Then it appears that a shadow is cast either on the sun or on the moon. This is known as on eclipse.
10) Solar Eclipse: While revolving, the moon, the earth end the sun comes in a straight line. When the moon is in – between the sun and the earth, the moon obstructs the sun’s rays from falling on the earth; it is called a solar eclipse. A solar eclipse occurs only on a new moon day.
11) Lunar eclipse: While revolving, the earth, the sun and the moon come in a straight line. Then the earth comes between the sun and the moon and obstructs the sun’s rays from falling on the moon. It is called a ``lunar eclipse’’. A lunar eclipse occurs only on a full moon day.