Moon is a natural satellite of Earth and its nearest neighbour in space. Moon is the first and the only object in the space to be visited by men. Men first landed on Moon on July 20. 1969.
Moon circles around the Earth in approximately 27 and 1/3 days in an elliptical orbit. The average distance of Moon from the Earth is 384,403 kilometers. The Moon also rotated around its axis in about the same time (27 and 1/3 days).
Average diameter of moon is 3476 kilometers,which is about 1/4th the diameter of Earth. The gravitational force on Moon is about 1/6th of that on Earth.
At night the Moon is the brightest object in the sky. But reality is that the moon emits no light. The sun appears to be bright only because of the light of the sun reflected by it. Moon appears so bright only because it is so near to the Earth. In reality stars are much brighter like the sun, but because of their distance from the Earth appear to be smaller and less brighter.
The phases of the Moon, or the changes in the shape of the moon from a complete round on a full moon night, gradually reducing to a thin crescent over a period of about fortnight on a new moon night, and again increasing to full moon in next fortnight. These phases of moon are caused by different parts of the sunlit side of the moon facing the Earth.
Moon has no life or air. Till recently it was believed to have no water on its surface. However just about a few months back a scientific satellite launched by India, has collected data that points to possibility of water on surface of Moon. This matter is still being investigated, and no firm information has been released to the common media.
Earth surface is marked by a very large number of craters formed by meteorites hitting the surface of the Moon. There are around 1/2 million craters which are 1.5 kilometer wide or bigger. In additions there are billions of smaller craters including some as small as 30 centimeters wide. Moon also has big plane areas, which appear as dark spots on the moon when seen with the naked eye from Earth. These plains have been formed by volcanic activity, which filled the depressions with lava.
The temperature of the Moon fluctuates much more widely than on Earth. The highest surface temperature in Moon is about 130 degrees centigrade and the lowest temperature is about -240 degrees centigrade.
Moon was formed at the same time as Earth about 4.5 billion years back. There are different theories put forward about how exactly the moon was formed. But there is no conclusive proof to support any one theory to the exclusion of others. The Moon could have formed as a separate small planet circling the sun and later attracted toward Earth to become its satellite when at sometime these two came very near. A second group of theories assumes that the Moon was a part of earth and got separated from it at a later date. A third theory is that the Moon has formed out of lot of loose material that was near the earth when the Earth was formed. These loose material collapsed together to form the Moon.
No comments:
Post a Comment