our new hope------ green energy: Post 6: Our Mighty Sun

Our Migthy Sun

1. sun : the center of the solar system

"Sun is the star of our solar system, its diameter is about 1392684km (about 109 times of that of earth!!!), and its mass is about 1.989*10^30 kg(about 3.3*10^5 times of that of earth!!!)"(#1). Let me give you an idea about the size of sun. If our earth is as big as a golf ball,that you can easily hold in hands, then sun will be as big as the tuned mass dumper(阻尼器) of Taipei 101!

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Although the mass and volume of sun are both enormous, its density is only 1.410 g/cm^3 which is around a quarter of that of earth. The density of sun is lower than that of earth, because sun is mainly composed of "light" element, such as Hydrogen and Helium. The picture below shows the composition of sun.

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If we take sun as an power generator, then Hydrogen will be the fuel. The reaction that generates tons of light and heat is called "Nuclear Fusion." I will just introduce nuclear fusion shortly at here, if you are really intrested in it, you can visit this website http://atropos.as.arizona.edu/aiz/teaching/a250/pp.html. Four proton(氫原子核) are converted into a Helium's nucleus(氦原子核) and energy. In fact, a Helium's nucleus is a little bit lighter than four proton, that is, some mass "disappear" during the reaction. By mass-energy equivation, mass can be converted into energy. Thus the mass dose not just vanish during nuclear fusion, it is just transfered into energy.

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2. Solar power on earth

Sun is a very kind, generous man, "the power he gives us is ten thousand times of the energy we use per year!"(#2) Remeber that I mentioned almost all green energy come from sun at my first post? Now, let me show you this amazing fact by the pcture below. It's a pity that we can't take advantage of solar power very well because we haven't developed a method to harness it efficiently. However, witnessing a lot of advanced coutries invest a lot of money in developing solar power, I am conviced that a revolution of energy will take place in the near future!

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