26 Mar 2012

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standard model
The Standard Model of particle physics is a theory concerning the electromagnetic, weak, and strong nuclear interactions, which mediate the dynamics of the known subatomic particles. Developed throughout the mid to late 20th century, the current formulation was finalized in the mid 1970s upon experimental confirmation of the existence of quarks. Since then, discoveries of the bottom quark, the top quark and the tau neutrino have given further credence to the Standard Model. Because of its success in explaining a wide variety of experimental results, the Standard Model is sometimes regarded as a theory of almost everything.

 Still, the Standard Model falls short of being a complete theory of fundamental interactions because it does not incorporate the physics of dark energy nor of the full theory of gravitation as described by general relativity. The theory does not contain any viable dark matter particle that possesses all of the required properties deduced from observational cosmology. It also does not correctly account for neutrino oscillations (and their non-zero masses). Although the Standard Model is believed to be theoretically self-consistent, it has several apparently unnatural properties giving rise to puzzles like the strong CP problem and the hierarchy problem.

5 Mar 2012

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E=mc2 what does it really mean
Energy=mass x the speed of light squared
One of Einstein's great insights was to realise that matter and energy are really different forms of the same thing. Matter can be turned into energy and energy into matter.
For example, consider a simple hydrogen atom, basically composed of a single proton. This subatomic particle has a mass of.
0.000 000 000 000 000 000 000 000 001 672kg
This is a tiny mass. But in everyday quantities of matter there a lot of atoms ! For instance, in one kilogram of pure water, the mass of hydrogen atoms amounts to just slightly more than 111grams or 0.111kg.
Einstein's formula tell's us the amount of energy this mass would be equivalent to, if it were suddenly turned into energy. It says that to find the energy, you multiply the mass by the square of the speed of light, this number being 300,000,000 meters per second:
E=mc2
=0.111 x 300,000,000 x 300,000,000
=10,000,000,000,000,000 Joules.


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