Asteroid Impacts Gave Crucial Spark to Early Life

Dec. 8, 2008 -- Better known as end-bringers than life-givers, asteroid impacts may have forged the chemicals essential for life in Earth's ancient oceans.

Between 4.2 and 3.8 billion years ago, in a period known as the Late Heavy Bombardment, space rocks rained down on the planet 100,000 times more frequently than they do today. It would seem an inhospitable environment for life to take its first tentative steps.

But new research on the chemistry of this fiery onslaught suggests the impacts produced a host of carboxylic acids, amines, and amino acids -- essential compounds for building proteins, and a food source for primitive organisms.

Yoshihiro Furukawa of Tohoku University in Japan and a team of researchers found how these complex molecules were forged in a laboratory experiment mimicking the impact of an iron and carbon-rich asteroid into seawater.

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"Carbon and nitrogen are already abundant in the atmosphere," Takeshi Kakegawa, also of Tohoku University, said. "But hydrogen and oxygen are still needed to form organic molecules."

That's where the asteroid comes in. In an impact, the iron in a meteorite acts as a catalysts to break up water molecules, allowing hydrogen and oxygen to bond with carbon and nitrogen to form the complex molecules.