Our Sun

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our sun

courtesy of NASA

Our Sun

Our Sun is a giant nuclear inferno at the center of our solar system. It's nuclear reactions are fueled by hydrogen (74%) which is converted into helium (25%) through a proton-proton reaction called fusion. It must be at least 8,000,000°K for this to happen and these temperatures exist only in the core of the sun. A star begins as a contracting cloud of gas being pulled together by it's own gravity. Compressed gas becomes hotter and hotter until the point of nuclear reaction.

The average distance from earth to the sun is 93 million miles. It takes light from the sun about 8 minutes to reach us. It takes light 6 years to reach Pluto. The diameter of the sun is 109 times that of the earth, over 1 million earths could fit inside the sun! An object at the Sun's surface would weigh 28 times as much as it does on Earth's surface!

The sun is about 4.6 billion years old and about halfway through it's life cycle of 10 billion years. (Larger, hotter stars have a shorter life cycle). Stars are continually converting hydrogen to helium through the process of nuclear fusion. Eventually the fuel (H) runs out and the nuclear reactions stop. Our star is a typical G type star based on it's temperature so it will eventually turn into a Red Giant and then cool to a white dwarf. Some larger stars end in a brilliant explosion called a "supernova". The largest stars will turn into a black hole, where the gravity is so strong not even light can escape it. There is a massive black hole at the center of our Miky Way galaxy!

sun erupt

courtesy of NASA

The solar flares in the pictues above are the equivalent of 10 million atom bombs! They are caused by a sudden release of energy stored in the magnetic feild. The energy released by one flare could power the United States for 100,000 years! Scientists are still researching these powerful explosions.

Although our sun is exciting and we cannot live without it, it is rather ordinary as far as stars go. It is one of a few hundred billion stars in our Milky Way galaxy, and there are billions of galaxies. If there are so many more suns...
Could there be intelligent life elsewhere in the universe?


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