Saturday, March 26, 2005

How to infinitely small rules the universe [part 1]

Some day in the near futur I'll have to make a speach to a amateur astronomer club of my region. I could have made one before but I lacked the "vision" and inspiration for a subject to talk about. This week end it hit me: How atomic laws and quantum mecanic are at the sources of just about every large scale thing in the universe (for dummies). This will be the first in a rather long series in the next few days, week months and is part of my blog deployement of weapon of mass education in the blog war (as of yet the UN as not decreated those weapon part of the non proliferation pact so I should be all right... I hope they don't change their mind I couldn't deal with an embargo right now). So without further delay here is the first part:

Small note on scientific notation: 4x10^6 means 4 times 10 to the 6 power or 4 millions

Stars energy source

Stars are powered by nuclear reaction more preciselly fusion reaction in which transform 4 ionised hydrogen atoms (free protons) into an hellium atom and a lot of energy (and a few other things not really relevent for a weapon of mass education). From Enstein famous equation E=mc^2, in each reaction ~4x10^-29 kg of matter is lost... that means that about 4x10^-10 J of energy is produce by each reaction. That is a very small number however the sun lose: 4x10^9 kg/s (that 4x10^38 reactions each second!) or 4 million ton of mass each second (see weight watcher try to match that!). This little parenthesis aside problem arise when you try to approch proton from each other. You may already know by experience that it require some force to push two identical pole of a magnect togeter. Since all proton are positively charge the same thing happen. So for the fusion to happen the proton in the stars must have enough energy to overcome this electrical repulsion. How do they do this? simple my friend heat and speed! The hotter a gas is the faster the particule in hit go and the more kinetic energy they have. At very high temperature the kinetic energy is large enough to beat the coulomb potentiel (the force pushing the proton away from each other). Once this potential as been breach the fusion can take place and produce the energy needed to created light, life and keep the stars from gravitational collaspe. As a star age (or when stars are much bigger then the sun) heavier element can fusion and that is what produce most of what exist here on Earth. So in a resumed manner that was how atomic laws rules stars light and the creation of heavy element in the universe.. Next, how light push things.

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