WASHINGTON - Tiny bubbles that can build themselves in the freezing vacuum of space suggest that life, or the seeds of life, could have originated out in space, scientists said yesterday.
In an experiment that duplicated the harsh conditions of space - cold temperatures, no air, plenty of radiation - they managed to get artificial cell membranes to form.
The membranes, which resemble soap bubbles, could act as primitive cell walls, David Deamer, a biologist who specializes in membranes at the University of California at Santa Cruz, said in a telephone interview.
"This wall is semipermeable. All membranes are semipermeable, so that things like water and oxygen get in and out very easily," said Deamer, who worked on the study. "That is what life requires: It needs to have an inside that is not totally shut off from the outside."
In an article in today's issue of the Proceedings of the National Academy of Sciences, the researchers said organic compounds from interstellar space might have kick-started life on Earth.
Deamer said the compounds have been found on dust from meteorites carried to Earth, and years ago these compounds were found to self-assemble into soapy, water-repelling bubbles.
When the National Aeronautics and Space Administration started its astrobiology program to search for life in space, researchers teamed up to see what it would take to make a cell in space.
"Scientists believe the molecules needed to make a cell's membrane - and thus for the origin of life - are all over space," the leader of the study, Louis Allamandola of NASA's Ames Research Center in California, said in a statement. "This discovery implies that life could be everywhere in the universe."
The researchers used simple, common compounds, which self-assembled into something that looked very much like a vesicle or cell membrane.
Such compounds could easily have been brought to Earth by a meteorite or asteroid.
"Maybe these molecules were just the raw lumber lying around that allowed origin-of-life chemicals to move in and set up housekeeping or construct their own houses," added Jason Dworkin, a postgraduate researcher at NASA who did much of the work on the study.