How do Stars Form?
From the pearls hanging in the sky to the demigods who control our destiny, stars, to different folks have different meanings. But here we will concern ourselves only with what the science says. So how are these jewels formed?
It all begins with a cloud of gas—a really big cloud of gas. The clouds are so big, that for comparison, if we think of the earth as an apple, then the cloud would be the size of our national capital, New Delhi. The clouds have hydrogen as its major component. These clouds are normally rotating at a very slow speed. Then comes into play the main ingredient; the gravitational force. Each and every molecule/atom in the cloud attracts each and every other particle. This creates some regions of uneven density. These regions of uneven density have even more gravitational force which helps them attract more particles and the cluster keeps on growing larger and larger. Then a point is reached when almost all the gas in the cloud forms a sphere. The left outs either wander away into deep space or form solid bodies which rotate around the star. This sphere of gas is called a protostar.
When such a sphere is formed, it begins to contract. It keeps on contracting and, as a consequence, the density of the sphere keeps on increasing. And a battle begins between the two forces: the gravitational force which wants to bring still more closely the particles of the sphere, and the electromagnetic force which wants to keep the particles away from each other. This creates a chaos, and in this chaos, the particles of the sphere go on continuously colliding with each other. These collisions produce a tremendous amount of heat, the effect of which is more pronounced at the centre of the sphere. The heat there keep on increasing until it reaches a temperature of 10 million degree Celsius. And then the miracle occurs.
The atoms of the gas fuse in the tremendous heat to ignite a kind of furnace. The hydrogen gas serves as a fuel to that furnace. Till such time the hydrogen lasts, the furnace keeps on burning, producing a massive amount of light and heat—leading to the birth of a new star.
What happens next?
If the parent cloud was large enough we would get a big star of blue color. Big stars burn hydrogen very fast and hence have a very short lifespan. If the cloud was not that large, the star that would form would be red in color. Smaller stars burn hydrogen at a relatively slower rate than the bigger stars and hence they last longer.
What is the difference between the sun and the stars?
There is no difference. The sun is a star and similarly, all stars are suns. Our sun was formed this way, and so were the planet earth we live on, or the moon we see and all other planets and their moons and other solid objects of our solar system. All these are made up of those left-out gases. Our sun is a medium-sized star and has already completed half its lifespan. But there is no need for immediate worry, as it still has 5 billion years to live.
