Answer:
Explanation:
The stars are great globes of hot, glowing gas just like our sun. They contain a great deal of hydrogen and helium gases. They shine by changing hydrogen into helium in the vast nuclear furnaces of their central core.
Astronomers have discovered that the stars contain most of the other elements found on the earth. They have identified more than sixty of the elements like air, water, fire etc. found on the earth. The elements are not in the same proportion as they are on the earth. They vary from star to star. The stars contain lighter elements like hydrogen, helium, iron and calcium in a large proportion.
Astronomers use an instrument called spectroscope to split the starlight into a broad band of colours. Sometimes there are a number of dark lines in the band. The position, the number and the size of the lines, give a lot of information about a star’s atmosphere including its gaseous chemical content, its density and temperature.