star

• clumps of dust and gas in a nebula come together due to gravity and form stars.

• stars are made of hot burning gases.

• they emit light of their own and are very large and very hot.

• light takes about 4.3 years to reach us from the next nearest star proxima centauri.                        
• Stars are heavenly bodies made up of hot burning gases, thus shining by their own light.

• Stars seems to be fixed with respect to each other, in fact they are in rapid motion but they are at such great distance that relative changes in position become noticeable only over the centuries.

• According to NASA proxima centauri is the closest star to the earth after the sun. it is about 4.24 light years away.

• Pole star (or polaris), Sirius, vega, capella, alpha centauri, beta centauri, proxima centauri, spica, regulus, Pleiades, aldebaran, arcturus, Betelgeuse and of course the sun are some of the important examples of the stars.

• Fact about stars.

• There are billions and billions of stars in the sky but only about 2000 stars can be seen with the naked eye on a clear moonless night.

• There are 10^22 stars in the universe.

• About 8000 stars are visible from the earth with naked eye. Out of this 4000 stars are visible in the northern hemisphere and 4000 in the southern hemisphere.

• In either hemisphere, only 2000 stars are visible at any given time.

• The other 2000 are located in the day time sky and brightness of the sun renders them invisible.