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Saturday, November 20, 2010

The Sun

Like a precious spring in the vast empty desert of space, the Sun makes our Earth a beautiful living oasis in the cold, dark universe around us.

What makes the Sun shine and keep on putting out such colossal amounts of energy for billions of years? It is amazing to me that, like most people, I didn’t ever ask that question when I was growing up. Maybe it was because the Sun is so awesome that I didn’t think anyone could possibly know the answer.

But Einstein figured it all out in 1905 when he developed his famous equation: E=mc2

That equation simply says that energy (E) and matter (m) are interchangeable -- one can be turned into the other. In the Sun, incredible amounts of energy (E) are created when very, very small amounts of matter (m) are destroyed. That’s because the constant (c2) that is on the same side of the equation as the mass (m) stands for the enormous speed of light multiplied by itself.

The Sun is made up of gases, about 75% hydrogen and 25% helium. In the very hot centre of the sun (15 million degrees Celsius), two hydrogen nuclei fuse when they collide, and the helium nucleus that forms as a result has a mass (m) that is very slightly less than the combined masses of the two hydrogens. That lost mass (m) is converted to the prodigious amount of energy (E) in the form of heat and light that the Sun gives off and has been giving off for billions of years. Watching this short YouTube clip helps visualize this thermonuclear reaction happening in the Sun.

So far the Sun has used up only about half its hydrogen, so no worries, there is no reason it won't keep flooding planet Earth every single day with an amount of energy that is equivalent to the whole of the world’s oil resources. That constant and beautiful supply of energy has been a major cause of the truly awe-inspiring evolution that has occurred on our planet – that, and of course the laws of nature.

One of nature's laws - the famous Second Law of Thermodynamics – says that in an isolated system, Entropy, or disorder, increases. But what about a system that is not isolated and that is receiving the wonderful energy from the Sun constantly? A relatively new theory, Complexity Theory, recognizes that if you pump energy into an isolated system, order will increase!!

Darwin certainly made great breakthroughs – recognizing evolutionary patterns and coming up with his ‘survival of the fittest’ dictum. But consider the tremendous driving force for the increasing complexity on the planet that is now being directed by us. And where do we get our energy? Indirectly, like everything else on Earth, from that marvelous thermonuclear reaction going on in the Sun! Rie

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