Test: The Earth- 1

A constellation is a group of stars that appears to form a pattern or picture like Orion the Great Hunter, Leo the Lion, or Taurus the Bull. Constellations are easily recognizable patterns that help people orient themselves using the night sky.

Earth also travels on an elliptical orbit around the Sun. And it takes one year to make a complete trip. In one year Earth makes one revolution around the Sun.

A rotation is a circular movement of an object around a center of rotation. The geometric plane along which the rotation occurs is called the rotation plane, and the imaginary line extending from the center and perpendicular to the rotation plane is called the rotation axis.

An equator is an imaginary line around the middle of a planet or other celestial body. It is halfway between the North Pole and the South Pole, at 0 degrees latitude. An equator divides the planet into a Northern Hemisphere and a Southern Hemisphere.

Earth is the only planet in the universe known to possess life. The planet boasts several million described species, living in habitats ranging from the bottom of the deepest ocean to a few miles up into the atmosphere. Researchers think far more species remain that have yet to be described to science.

The earth takes about 24 hours to complete one rotation around its axis.

As the Moon moves around Earth in its orbit, the light reflecting off the side of the Moon creates a sliver of shape. This is a crescent moon. Because it's getting bigger, we can also call it the waxing crescent moon.

The Earth rotates on its own axis and it rotates in the eastward direction and in a counter-clockwise in prograde motion. So the direction of the earth's rotation is considered as from west to east.

The earth rotates once in 24 hours. Since the rotation of the earth in the direction from west to east, the moon, sun, and all other celestial bodies appear to move from east to west. This is the reason for which we say the sun rises in the east and sets in the west.