(ESTD. BY GOVERNMENT OF TAMILNADU)


Sun


The Sun is a star at the centre of the Solar System. All the planets and other minor objects revolve around it. The surface of this burning ball of gas is 5500ēC.

But, deep inside the Sun, the core temperature remains at a sweltering 150 lakh ēC The Sun is so large you could fit over 10lakh Earths inside it Variations in the Sun's magnetic field cause huge jets or loops of stellar material to shoot out into space. These are solar flares.

Solar flares can be accompanied by dense clouds of electrically charged particles, travelling at around 450km per second.

When they reach Earth, they can affect communications satellites. Earth’s magnetic field protects us from these harmful high-speed particles.

The solar wind when interacting with the atmosphere causes the beautiful display of aurorae in the Polar Regions.

Life on Earth is totally dependent on the energy it receives from the Sun. This energy is produced when hydrogen atoms inside the Sun fuse to form helium.

The Sun consumes four million tons of hydrogen every second. Even so, it's so vast that our star has enough fuel to keep it shining for another five hundred crore years.

After that, when that fuel is exhausted, the sun will change. As the outer layers expand to the orbit of the earth or beyond, the sun will become a red giant star, slightly cooler at the surface than at present and 10,000 times brighter.

It will remain a red giant, with helium-burning nuclear reactions in the core, for only about 50 crore years. After the red giant stage it will shrink to a white dwarf star, about the size of the earth, and slowly cool for several billion years.

The Sun's energy output is estimated to be 38,60,000 crore crore megawatts every second. So in 15 minutes our Sun radiates as much energy as mankind consumes in all forms, during an entire year.