If you stand on the pavement by the side of a busy road and take a look at the traffic that seems to move past endlessly – the cars, the buses, the scooters and other numberless vehicles and the sea of people sometimes surging slowly inch by inch, sometimes whizzing past as if possessed, you will surely wonder at the magnitude, the speed and the hurry-oh! Where do all these go? To their homes? Why so much hurry? Surely the city that accommodates all these must indeed be very vast and spacious.
Perhaps your wonder will be greater if you look at the sky on a clear moonless night – the entire dome seems to be lit up with countless points of light some white, some red and some yellow, a few steady but many twinkling, their numbers will amaze you. If you begin to count, sure, you will be lost in no time, though they do not seem to be many, only a couple of thousands, if seen with the naked eye. But in reality, there are millions and millions of stars varying in size and brightness. There are giants and super giants and dwarfs too- radiant marvels in the depths of space where may be found the original stuff- the matter, from which all things are made.
When you look at the night sky many beautiful stars can be seen. There are different kinds of stars in the sky. These stars which are glowing balls of gases are fixed. Some of them are really very big. Some are small while some are medium – sized. Of these numberless stars, our sun is one and it is a medium – sized star. The closest star to the earth is sun and that is why it appears to be big in size. The closest star to the earth after sun is Proxima Centauri also known as Alpha Centauri C. It is the dimmest star in the Alpha Centauri system. Proxima Centauri is 4.3 light years away from the earth.
Stars are present during the daytime as well. But they are not visible because of the bright light of the sun. The sun is the only star visible to us during day time. All the stars appear to move with respect to the earth and change their position with time. Only one star does not change its position with respect to the earth, this star is known as the Pole star. It is also known in the name of Polaris. In the Indian astronomy, it is known as the Dhruv Tara or Laghu Saptarishi. It lies close to the axis of the earth.
If you observe the night sky carefully, you might see different arrangements of stars in the sky. That is known as a constellation. Constellations are named after prominent objects known to ancient people. There are 88 standard constellations known by the International Astronomical Union (IAU) since 1922. It was founded in 1919. Its mission is to promote and safeguard the science of astronomy in all its aspects through international cooperation. Some of the famous and important constellations seen in the night sky are Ursa Major also known as the Great bear, Ursa Minor also known as the little bear, Orion often referred to as the hunter and Cassiopeia also known as Sarmishtha.
All these are present in our galaxy which is the Milky Way or Akash Ganga and all these started with a big – bang. Surely, there is nothing in the world which can be more mysterious than space.