Friday, August 24, 2012

The "broth of life" could cook with element alien

The examination of meteorites realizes too much numbers of left-handed amino acids. There is more evidence than ever that life on Earth may have originated as a result of material from asteroids or comets. Previous research had already shown as amino acids, the structure blocks for constructing natural life could form anywhere in the universe.

These molecules can form in two different versions, but life on Earth is based on only one of them. Now research published in the Astrophysical Journal Letters shows how conditions that 

occurred around a very distant star could have favored the formation of a type of amino acids over the other.

Without explanation

Amino acids are molecules with a corkscrew shape can be formed by turning clockwise or counterclockwise, and the chemistry favors no intrinsic shape is formed in one direction or another. But, without exception, nature uses only the version you prefer, turn left. A famous experiment conducted in 1952 showed how a spark in a soup of chemicals representing the primordial Earth could form amino acids.

As many of the experiments followed, produced in the same number revolving toward the left and to the right. The idea that amino acids could have reached Earth via meteorites, which in turn are formed by asteroids or comets, study provided another route. And the investigation of meteorites realizes majority of left-handed amino acids.

Last week, the NASA astrobiologist Daniel Glavin and his companions followed that track and announced that his research showed that a large number of types of meteorites could hold majorities of the same type. However was to determine the mechanism by which these versions of left-handed amino acids are preferentially produced in the cosmos to be later picked up and taken to Earth.

Circular argument
Now, Uwe Meierhenrich, University of Nice Sophia Antipolis, France, and his colleagues have found a method by which one could explain this "symmetry breaking" natural. Began taking frozen pieces of material contain various simple molecules: water, methanol and ammonia, from all ingredients which can form amino acids. Subsequently expose to a particular type of ultraviolet rays.

The type of light has a polarization, which means that the beams oscillate along a particular direction, up or down, right or left. Although we cannot directly see this effect is somewhat apparent when using a polarizing sunglasses that block the reflected light tends to be polarized and along the line from right to left. In contrast, the light used by researchers is what is known as circular polarization. More than one direction, the polarization traces the shape of a corkscrew.

It is known that the light in the region where there is the birth of a star is polarized circularly and having to go through a lot of clouds and granular powder that is aligned by magnetic fields. Did you choose the life of a random one form over the other? It seems that Nature helped a bit.

Daniel Glavin, an astrobiologist at NASA

Experiments showed that the circularly polarized light both versions of driving left and right hand of amino acids. But there were just over 1% additional versions left. This is the same level of excess that Professor Glavin and his colleagues found in meteorites found on Earth, and the mechanism is a fact to argue convincingly the extraterrestrial origin of the first amino acid of the Earth.

"We must break the symmetry in some way, because this is key. Breaks But how? This is one of the most important issues: life chose randomly one form over the other? Seems Nature helped a bit "Glavin told the BBC. However astrobiologist said molecules can change their shape and that a mixture of the two type’s uneven end terminating in a mixture with the same time, a chemical process called raceme mixture.

"These are exactly the kind of experiments we need to do but we need to keep in mind the big picture," he said. That is, to bolster the idea that life on Earth began with the sending of a package of extraterrestrial ingredients still must specify the mechanisms by which the unequal mixture can be preserved in the long day's journey from the formation of distant stars.

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