London, Jan 10 : A leading astrobiologist has added another hypothesis to the existing long and varied list of the theories for the origins of life, by claiming that the basic building blocks of life on Earth began on a radioactive beach.
According to Zachary Adam, an astrobiologist at the University of Washington in Seattle, life on our planet first evolved through the collection of radioactive material on a beach.
He suggests that the more powerful tides generated by the moon's closer orbit billions of years ago compared to today could have separated radioactive material from other sediment.
With the help of computer models, Adam points out that sufficient amounts of radioactive deposits accumulated at a beach's high tide mark triggered the self-sustaining fission reactions.
Demonstrating his theory in lab experiments, Adam showed that such a deposit could generate the chemical energy which is required to produce some of the molecules in water that create amino acids and sugars, the key building blocks of life, when irradiated.
Adam added that a deposit of a radioactive material called monazite would also discharge soluble phosphate, another important ingredient for life, into the gaps between sand grains, thus making it available to react in water.
"Amino acids, sugars and [soluble] phosphate can all be produced simultaneously in a radioactive beach environment," New Scientist quoted him, as saying.
Other hypothesis explaining the evolution of life on Earth includes English geneticist J. B. S. Haldane and Russian biochemist Alexander Oparin's "primordial soup" theory.
The theory, devised in 1920's, proposed that life on Earth emerged from a "primordial soup" of simple organic chemicals accumulated on the surface of bodies of water within the hydrogen-rich early atmosphere.
Others include early life forming in inorganic clay, the initial energy coming not from chemical reactions but from sunlight or lightening and the influx of microscopic seeds of terrestrial life on chunks of meteorites or comets, and the intervention of a divine, intelligent designer.
Adam's study is published in this week's New Scientist magazine.