A group of scientists says it has collected an alien bacterium 10 miles (16 kilometers) above Earth, plus signatures of other extraterrestrial microbes even higher in the atmosphere. The claims were met with immediate skepticism by other scientists.
The bacterium was collected at that altitude by a balloon operated by the Indian Space Research Organization. Chandra Wickramasinghe, who leads a study into the results, called the microbe a previously unknown strain of bacteria and said it likely came from a comet.
Wickramasinghe and a colleague, Fred Hoyle, say the findings support an idea they pioneered, called panspermia, which holds that the seeds of life are everywhere in space and are the source for life on Earth.
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Matthew Genge, an expert on meteorites and cometary debris at London's Natural History Museum, said he was flabbergasted by the claim.
"I don't believe the authors have provided the kind of evidence that would be needed to support their claim," Genge said. "Their announcement appears premature."
Genge, who does not rule out panspermia as a possibility, said nonetheless that the supposed alien bacteria could have been previously unknown strains of terrestrial bacteria.
"Hitherto unknown strains of bacteria are found virtually every day," Genge told SPACE.com. "If no one had ever seen or heard of an elephant and suddenly one was discovered this wouldn't be evidence that it comes from space."
Wickramasinghe countered that procedures precluded the instruments aboard the balloon from being contaminated on the ground or on the way up, but he acknowledged the possibility of contamination at the point where the collection was made.
"Earthly bacteria could get up to 15 kilometers from several sources," Wickramasinghe told SPACE.com. "Also there is a chance that unknown strains of bacteria were lofted from the heights of the Himalayas."
Wickramasinghe said his group wouldn't reveal details until the microbe is studied further.
High-flying bacteria
Genge echoed the cautions of other scientists in saying that dust carrying terrestrial bacteria had been found in the collection filters of NASA U-2 aircraft doing similar research for 15 years.
"There is in fact enormous amounts of dust from the Earth's surface at high altitude, both artificial and natural in origin, and some of it undoubtedly carries bacteria," Genge said.
"Another possible form of contamination could also be human waste," Genge said. "Passenger aircraft fly at 10 miles altitude and eject human waste into the atmosphere. A fine spray of such liquid released into the atmosphere at high altitude will form tiny ice grains containing bacteria. These will become widely dispersed."
NASA also commented on the claim, pointing out that living spores have been found previously as high as 10 miles.
"While NASA's astrobiology effort has certainly not come down on the side of panspermia, it has identified panspermia as worthy of serious investigation, along with more conventional ideas about the origin of life on Earth," said a press release out of NASA's Ames Research Center.
Other scientists also urged caution in interpreting the results. Meanwhile, recent studies by other groups have boosted panspermia into the spotlight, and many leading researchers are warming to the idea that microbes may be hardy enough to endure the rigors of space travel.
Next page: New evidence of more microbes at 52 miles (83 kilometers) up
on this data, produced by a team led by Ray Russell of the Aerospace Corporation, found organic compounds indicating that the building blocks of life could have survived a trip from space to Earth.Working with the Leonid fireball data in a separate study, the Cardiff team concluded that the fireball actually did contain a signature of microbes that rained down from space. The study analyzed the infrared light emitted by the fireball, which the researchers say showed signs of burning bacteria. Further, they say this signature resembled the infrared spectra of comet dust.
"There is little chance of any earthly bacteria resident at such great heights," Wickramasinghe said.
But Genge flatly refuted the group's analysis of the Leonid fireball data.
"The infrared spectra of the Leonid meteors are not evidence for bacteria, nor are the infrared spectra of comets," Genge said. He added that the data show a feature that is common in all organic material.
"If you took me, put me in an oven, dried me at 300 degrees and then took my infrared spectra, I'd have [this feature] too. This would certainly not be evidence that you'll find Matt Genges on comets.
The whole debate is reminiscent of claims of microscopic fossils in a meteorite from Mars, reported by NASA scientists in 1996. Scientists are still debating that finding.
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