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Bacteria survived Columbia explosion, sparking scientific leap


http://www.statesman.com/

Researcher finds evidence to support ancient theory.

Austin-American Statesman (02/22/2006)
By Miguel Liscano

SAN MARCOS—When the space shuttle Columbia broke apart over East Texas in 2003, killing all seven astronauts aboard, Texas State University biology professor Robert McLean thought his bacterial experiment package on board had been destroyed. Then it was found mostly intact in a Nacogdoches convenience store parking lot and returned to him.

Now he says it's evidence that furthers a theory called panspermia: the hypothesis that life can travel through space by hitchhiking from one world to another on meteorites.

McLean said Microbispora was not one of the bacteria involved in the original experiment — studying interaction between three species in microgravity — but he determined before launch that it had contaminated one of his specimens.

"This organism appears to have survived an atmospheric passage, with the heat and the force of impact," McLean said in a written statement. "This is important for panspermia, because if something survives space travel, it eventually has to get down to the Earth and survive passage through the atmosphere and impact."

McLean says his findings do not prove panspermia because the bacteria traveled about a fifth of the speed that a meteorite would travel. But, he said, it was at least six times faster than anything tested before.

His findings will be published in the May issue of Icarus, the international journal of solar system studies.

Evidence of the panspermia theory stretches back to the writings of the Greek philosopher Anaxagoras, according to the online Encyclopedia of Astrobiology, Astronomy, and Spaceflight. Then, in the early 20th century, Swedish chemist Svante Arrhenius said that life, in the form of spores, could survive in space and spread from one planetary system to another by radiation pressure, the Web site said.

There has been little testing of panspermia because of the conditions needed for study.

"This is another piece of the puzzle that shows it is more plausible than has been previously thought," university spokesman Jayme Blaschke said.