As we know, the Sun is our main source of energy, it is
an ordinary star that lies about 28,000 light years from
the centre of our galaxy, in one of its spiral arms.
Although the Sun is just a medium sized star compared to
other stars in the galaxy,it is absolutely huge compared
to the planets of our solar system. It's diameter is
approximately 1,392,000 kilometers(865,000 miles), more
than a hundred times of that compared to earth's. The
sun's mass is about 2*10^21 tonnes
(2,000,000,000,000,00,000,000 tonnes). That massive
fireball contains about 99% of the total mass in the
solar system. In the core of the giant, the weight of
the hydrogen pushing down makes the environment dense
and hot enough for hydrogen to be fused together into
helium by a nuclear reaction known as nuclear fusion.
Some of the hygrogen is changed exactly into energy,
and to be exact,the Sun uses up 400 million tonnes of
hydrogen in a second. The amount of energy produced is
so immence that the temperature when the reaction occurs
can reach up yo 15 million degrees celsius.
PARTS OF THE SUN
The outer layer is called the corona, which oooks like a white halo during a solar eclipse, containing particles at temperature of millions of degrees. And there is the yellow surface that we see is called the phrotosphere and the temperature there is about 5,500 degrees celcius. Many people think that the sun is a burning rock, but it's been proved wrong. The Sun is a ball of hydrogen with a helium core. The outer part of the sun is fusing and it transports the heat to the phrotosphere for it to radiate.
Many solar activities occur in the sun, like sunspots and Solar flares. Sunspoits are caused by strong magnetic force in the Sun and can last for many months, but one normally disappear in 10 days or so. They usually occur in groups, but individual spots can measure kilometres across. These spots are darker but as bright as full moons.Also, they are 1,500 degrees cooler than the rest of the photosphere. However, solar flares are the opposite. Flares happen near the sunspots. In the flare, enormouse amount of energy is given off in just a few minutes, causing the temperature to rise up to more than 100 million degrees celsius. These hot stuffs produce X-Rays, radio waves and clouds of atomic particles that shoot into space.
WILL THE SUN DIE?
When will the sun exhaust its hydrogen supply? Scientists have predicted that the sun would still last for about 5,500 years million years and when it does die, it will expand a hundred times larger than it is now and will engulf the earth in the process. The sun's outer layer of gas will be thrown off to become a shell of glowing gas, commonly known as a planetary nebula. The giant's temperature will then fall and become a red giant. It then shrinks and thereby becomes a white dwarf. At this point of time, one teaspoonful of the sun's material would weigh over a tonne as the whole sun's mass is concentrated in that white dwarf. The white dwarf cools and as time passes...
[9 major planets]
By TNN & Co.
By TNN & Co.