The Universe which exists in space is very big. It is beyond human imagination. And a tiny part of the Universe is The Milky Way Galaxy. And the Solar System is a small part of The Milky Way Galaxy. And the Earth is a part of this solar system. So, now it’s quite understandable how enormous our universe is. ( Watch this video to have a perspective)

• The moon moves around the earth.
• The moon completes one revolution around the earth in 27.3 days.
• The moon is the only natural satellite of the earth.
• The surface of the moon has great plains and big mountains.
• There is no life on the moon as it has no water and air and also it lacks atmosphere which protects against the strong harmful rays of the sun.
• No sound can be heard on the moon due to the absence of air.
• Neil Armstrong and Edwin Aldrin became the first men to step on the moon on 20th July 1969.
• They were carried on the moon by Apollo 11 spacecraft. (Link for further reading)
• The moon’s gravity is one-sixth(1/6th) of the gravity of the earth.
• The rhythmic rising and falling movements of the ocean water are known as tides.
• The gravitational forces of the sun and the moon combine to pull on earth’s water causing the tides.
• The surface of the water where it is pulled up it forms the high tide and where the water is lowered if forms the low tide.
• When the moon comes in between the sun and the earth, the moon is not visible to us, this is known as the new moon.
• When the earth comes in between the sun and the moon, a full moon is visible to us, this is known as the full moon.
• The different shapes of the moon that is visible to us are called the phases of the moon.
• The first artificial satellite sent into space was Sputnik-I which was sent by USSR on 4th October 1957.
• First Indian artificial satellite sent into space was Aryabhatta.
• Other Indian artificial satellites are Rohini, INSAT-1B. 

The uses of Artificial Satellites are:

• Brings us television pictures from the other side of the world.
• Satellites are used by ships or planes to help them navigate.
• Some satellites are useful to take photographs of the earth.
• Communication satellites are helpful in giving us the live coverage of the events happening anywhere in the world.