Evidence of amino acids and other hydrocarbons from meteorites were brought under close scrutiny when small oil structures were flushed from the Murchison meteorite. Previous observations of such structures had been put down to terrestrial contamination by microorganisms, as they are remarkably similar in chemistry and structure to the phospholipid membranes of living cells.
Lipids are fatty acid chains that have joined together and although the globules, or coacervates as they have become known, are not actually composed of fatty acids they act appreciably like them and are chemically very close. Phosolipids are lipids that have lost one of their fatty acid tails and have a phosphate group instead. Lipids and other fatty substances act as complex fluids which can form interconnected networks or tiny little enclosed worlds in the form of globules very much like those flushed from the meteorite.
The fatty acid-like substance that produces these globules is called PAH, which structurally is very close to the cell membranes. Could these soap bubbles from outer space have landed on a lifeless earth to help the formation of life make a great leap?
It is thought by some scientists that these globules could have acted as microenvironments for the synthesis of steadily more complex hydrocarbons. The molecules that would be far too dilute and unconfined in their natural environment, such as the Earth's early oceans, would have been able to pass through the oily outer layer of these globules due to their ionic distribution. Once inside they find themselves in a steadily more and more concentrated solution in a confined area, which through random chance allows more collisions and reactions to take place.
However once the molecules have reacted together they have altered their shape, size, and charge distribution, which may have prevented them from re-exiting the structure. This would solve the problem of the constituent building blocks being in a harsh chemical environment in very dilute amounts, except that in order for the globules to remain globules and not become random oil slicks on the surface of the water they themselves have to be in relatively high concentrations.
Perhaps a meteorite like the one found at Murchison could have dropped into a coastal region or Darwin’s warm little pound!
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