The Sun

                              The Sun

The Sun is a huge burning ball of gas at the centre of the Solar System. It is the energy giving star to the whole Solar System. The Sun is about 1.4 million kilometres in diameter and 109 times bigger than the Earth. It is 's yellow star of about five billion years old, consisting entirely of hydrogen and helium. The visible surface of the Sun called photosphere has a temperature of about 5,500°C. Dark, cool patches caused by magnetic fields which appear on the photosphere are called Sunspots. Other short-lived activity on the surface of the Sun are flares and prominences. Sudden release of high energy radiation and atomic particles are flares, and huge glowing hydrogen clouds are prominences. The inner atmosphere of the Sun is called chromosphere. The outermost surface which covers the Sun with a thin cloud of gas is the corona. Tiny particles that drop out from the corona cause the solar wind. The corona and chromosphere can be seen only during total solar eclipse.

                    Solar Energy

Solar energy is emitted through a process called nuclear fusion. The four hydrogen nuclel in the Sun join to form a helium nucleus. This process converts a small amount of matter into energy A large quantity of energy is emitted during nuclear fusion This energy is liberated as heat, light and other radiations.

                          The Sun

Diameter: About 1,392,000 kilometres (109 times that of the earth) 

Mass : 332,946 times that of the earth Volume: About 1,300,000 times that of the earth.

Temperature: Surface: about 5500°C 

Centre: about 15,000,000°C

Rotation period: 25.38 days at equator 

Age: 4.6 billion years

Average distance from the earth to the sun: About 150 million kilometres 

Time required by sunlight to reach the earth: About 8 minutes and 20 seconds