The Earth’s Natural Satellite
The moon is our closest neighbor in space and is the brightest and largest object to be seen in the night sky. In reality it is very tiny compared to the planets and stars. It looks big to us because it is the nearest to our earth, only 384,400 kilometers away. Compare this distance with earth’s distance from the Sun. The Soviet probe ‘Luna 2’ landed on the moon for the first time in September 1959, while the USA landed the first men on the moon on 21st July 1969. What were their names ? Who was the first man to step on the moon’s surface ?
We know today that the surface of the moon is dusty and full of craters that were formed between 4.6 to 3.5 billion years ago. In the early years of the formation of the solar system, thousands of meteorites bombarded the moon to form these craters. These craters have been carefully preserved, because the moon has no atmosphere, volcanoes, water or earthquakes, which would change the appearance of its surface. The moon surface gets very hot during the day (165oC) and becomes very cold at night. Temperature dips down to as low as minus 155oC. Do you think that life can exist on the moon in such conditions?
The moon spins on its axis almost exactly in the time it takes to journey around the Earth, i.e. eastward in 27.3 days. Scientists explain that the earth’s gravity has ‘braked’ the moon’s spin gradually. It was faster earlier. As a result, we see the same side of the moon – the nearer side. The far side was seen only after October 1959. Each night the shape of the moon seems to change. These changes are called the phases of the moon.