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...is a 5 billion year old star, and is considered to be in the middle phase of its existance. We rely on the Sun for our very exsistance, without the sun, nothing can grow on our planet. Because our sun is our only natural resource for heat and light, our planet will go into a deep freeze, when our Sun dies. The Sun's size is enourmous, about 3 million miles around its equator. The Sun travels about 700, 000 miles per hour, hurtling through space, carrying all planets, including us, with it.
The Sun is made of many layers. The core is called the radiative zone, it reaches temperatures of about 14 million degress C. The layer around the core is the convective layer, then photoshpere, chromosphere (the first layer of its atmosphere where temperatures come down to a cool 6000 degrees C.) Finally, the corona gases, which is it's outside layer.
Solar flares are huge explosions of energy that form in the Sun's core, then sent into space. On Earth they can sometimes be spotted, they are called aurorae.
A couple billion years from today, our Sun will run out of hydrogen and the star will begin to contract. This contraction will cause energy in the core to blaze even hotter then now. This new energy will force the outer layers away from the core and our Sun will become a Red Giant. Its size will grow about one hundred times it's present size and it will burn 500 times brighter. Our Earth will become a sea of hot, molten lava everywhere. The Sun will then begin to shrink into a white dwarf star.