The Begining of Life

Life began on Earth billions of years ago and has evolved greatly to the present date. We have wondered for a long time how life came to be. We're already gotten some clues when comets were examined and we found that they had similar amounts of the chemicals that make up humans (Nitrogen, Oxygen, Hydrogen, and Carbon). Ronald Breslow, Ph.D., University Professor, Columbia University, and former ACS President, described how our amino acid signature came from outer space. Firstly, chains of amino acids make up the protein in people and life. There are two forms of amino acids: the left and the right, which mirror the other in much the same way human's left and right hands mirror each other.
This is known as "chirality." In order for life to arise, proteins must contain only one chiral form of amino acids, left or right, as noted by Ronald Breslow.

"If you mix up chirality, a protein's properties change enormously. Life couldn't operate with just random mixtures of stuff," he said.
On Earth, left handed amino acids dominate. Breslow explained how this compusition of amino acids came to be: as asteroids fly past stars in space, one type of amino acid is destroyed. Stars emit polarized light circularly and thus, on one side, it emits right-polarized light, and on the other, it emits left-polarized light.
Previous experiments have proven have circularly polarized light destroys one type of amino acid over the other, causing an excess of about 5-10% over the other. Asteroids begin with an equal amount until they are affected by this light. In this case, the L-amino acid was the excess.

There has been much proof indicating this L-amino acid domination in experiments and instances of finding meteorites where they had an excess of L-amino acids on the surface. The professeur showed how L-amino acids could become dominant with an experiment starting with a 5% extra of one the L-amino acid and disolving it in water. As the amino acids combined and the water evaporated, it left a huge dominance of L-amino acids and it was chosen selectively by living organisms.

There have been other theories put forth but the evidence behind this theory is overhwelming.
With this discovery, we are closer than ever before, to discovering how life begins and the fact that there could very well be other life on Earth.