Working with nothing more than some frozen gases and a blast of ultraviolet radiation, Louis Allamandola has synthesized primitive cell-like structures more evidence that chemical reactions in interstellar space helped jump-start life on Earth billions of years ago. Scientists first discovered similar organic spherules inside carbonaceous meteorites more than two decades ago, but nobody could explain how the proto-cells formed. A group led by Allamandola, an astrochemist at NASA's Ames Research Center at Moffett Field in California, decided to re-create the conditions in the gas clouds where our sun was born. They zapped a mix of water, methanol, ammonia, and carbon monoxide ices with the kind of energetic rays emitted by hot young stars. In the end, about 2 percent of the frozen gas transformed into oily organic molecules.
|Courtesy of NASA|
When dipped in water, the compound spontaneously forms multiwalled chambers similar in size to living cells. Some of these bubbles glow under fluorescent illumination, meaning they transform ultraviolet into visible light. In short, the proto-cells provide two services essential to life: They have membranes that protect the chemistry going on inside, and they convert destructive high-energy radiation into useful, less intense energy. Allamandola thinks self-replicating molecules might have arisen inside these bubbles, then co-opted their structure to form the first living cells. "This experiment tells us that the kinds of molecules critically important to life's development can exist everywhere in the universe," he says.