Question: why do we have stars

Shikha Sharma answered on 11 Nov 2014:

Hi 328bera39,
Long back our universe was completely dark and very hot. There were only dense cloud of protons and electrons. It was so dense that even light couldn’t pass through. Hence it was completely dark. It remained such dark for 650 million years. As universe cooled down, protons and electrons started combining to form Hydrogen. As free electron reduced, it created passage of lights and our universe became visible. Dark age ended. Later due to gravitational force Hydrogen atoms comes together to form large clouds and formed gigantic starts. Inside the core of stars hydrogen atoms started converting into heavier atoms mostly Helium and emitting enormous energy inform of light and heat. This is called fusion. This is what happens when an atom bomb blasts. So the stars are combination of billion & billion atom bombs. Those early age stars are no longer exist. Because they burnt all its Hydrogen fuel, lost all energy, stopped emitting light & heat and finally died. It is like; we take birth, grow, work, loose our energy and die. But formation of stars is continuous. Even today we see new stars are being formed in universe with powerful telescope. Thus we see so many stars around us. In our observable universe there are approximately 100,000,000,000,000,000,000,000,000,000 (29 zeros after 1) stars we can see.
That’s really a big number 🙂