mention effects of earth's revolution.

When watching the stars at night, they do appear to move very slowly. This is because the Earth is constantly moving. The Earth completes

one rotation every twenty-four hours. A rotation is when the planet spins around once. The Earth rotates counterclockwise; this is why the Sun rises in the East and sets in the West. It is not the Suns movement that causes days, but rather the Earth turning around in front of the Sun. The Earths axis (the point at which it rotates around, for example, if you were to spin around while standing in one spot, your axis would be an imaginary line running through your head straight down to your feet) is in line with a star named Polaris. Polaris is also known as the North Star since it is directly above the Earths axis. Since this star is directly above the Earths axis, it does not appear to move, however the rest of the stars in the sky move around Polaris (for example: when you spin around, the object directly above your head does not appear to move but everything else seems to spin around that object). Polaris is only seen in the Northern hemisphere and it belongs to the Little Dipper constellation (its the last star at the end of the handle).

Another type of motion is known as revolution. Revolution is when one object completes a circular path around another object. The Earth takes 365.24 days to revolve around the Sun. This is why a year is 365 days long. During the year the Earth is angled differently towards the Sun. These changing angles provide us with different Sun intensities and therefore we get four different seasons. Since the Earth is at different positions in space over the year, we see different constellations throughout the year.

Coriolis Effect:Defection of wind due to rotation of Earth

UP [NORTH]:WestDOWN [SOUTH]:East (On Surface)

Northern Hemisphere:Deflected to the right (clockwise)

Southern Hemisphere:Deflected to the left (counter-clockwise)

Trade Winds:high pressure wind blown to the west from 30N

Westerlies:deflected to the east

Earth is currently in a cool phase characterized by formation of glaciers (glacial maxima), followed by warm periods with glacial melting (interglacialperiods). These glacialinterglacial cycles occur at frequencies of about 100,000 years. We are currently in an interglacial period; these have lasted about 23,000 years in the past. The last glacial maximum was about 18,000 years ago.

The glacialinterglacial cycles have been explained by regular changes in the shape of Earths orbit and the tilt of its axis—Milankovitch cycles.

Circular rotation causes glaciers to melt; more solar radiation; Elliptical= less radiation. The intensity of solar radiation reaching Earth changes, resulting in climatic change. The shape of Earths orbit changes in 100,000-year cycles. The angle of axis tilt changes in cycles of about 41,000 years. Earths orientation relative to other celestial objects changes in cycles of about 22,000 years.