August 3, 2012

Asymmetry in nature: The story of our existence


We have seen symmetry everywhere around us. We say everything that is good has something bad too. If we approach this symmetry from Physics point of view, there are electrons and opposing them are protons, then there are neutral particles called neutrons. These three particles are responsible for everything around us, everything we call matter.
But as I have learned, matter and anti-matter is always created together. And keeping the symmetry, matter and anti-matter must have been in equal amounts . We see matter, so where is this anti-matter?
Well of-course the answer lies in the universe outside our earth. As we have seen from Hubble telescope, all the galaxies around us are moving away from us. That means that our universe is expanding. This conclusion gave birth to a new theory, the only one that explains the violent start of the universe and its expansion. And according to this theory, everything must have been at the same place, all galaxies and stars collected together between some 10-15 billion years ago.
Do you remember Einstein's mass-energy equation, E = mc². That equation is a fact, and another fact is that the matter and anti-matter were created together. These two facts taken together implies that ten-billionths of a second just after the Bing bang, the entire Universe would have fitted into a single room, where energy and matter were completely exchangeable - temperature, billions of billions of billions degrees. New particles and anti-particles were created all the time and annihilated back into energy.
So where did these antiparticles go? There should have been equal amounts of matter and anti-matter. But somehow, scientists could not understand why, a small surplus of matter appeared; for every billion anti-matter particles, there were a billion plus one matter particles. Nature created very little asymmetry, which gave birth to all of the universe. This asymmetry gave a kick to the Universe which tipped to the 'matter side'. And as matter increased, within a second the whole of the anti-matter part of Universe was destroyed to nothing. While expanding the temperature continuously dropped till it reached a point where no more particles and anti-particles can be created and all that left was a little amount of matter, which we see as our Universe.
Does that mean, we owe our existence to a little asymmetry between matter and anti-matter? Yes, without that asymmetry, there would have been no universe, no earth, no humans. Universe would have been nothing but light in an empty space.