

Three new bacterial species found in the upper stratosphere are probably not alien visitors — but they're still quite remarkable.

The microbes were collected in a balloon sent by the Indian Space Research Agency to the boundary between Earth's atmosphere and space, and are extremely resistant to ultraviolet radiation.

One species was dubbed Janibacter hoylei, a reference to astronomer Fred Hoyle, who believed that Earth's first life came from space. In a press release, the agency noted that the bugs "are not found on Earth" and that "the present study does not conclusively establish the extra-terrestrial origin of the microorganisms" — implying, of course, that they might be alien in origin.

Not so fast, said University of Washington astrobiologist John Baross.

"It is extremely unlikely that these organisms are extraterrestrial," wrote Baross in an email, "and they are likely to originate from soil on Earth."

Bacteria is often found in the stratosphere, and most can be traced to wind-borne dust particles. That the new species were previously unknown means little. Scientists have identified just one percent of all Earthly bacteria. And though the species hadn't been seen, their gene sequences were familiar; they represent a variation on known life, rather than an entirely new form.

But they might still be useful, said Baross. For years, researchers have wondered if bacteria might be capable not only of surviving space, but growing in it. If the new bugs turn out to thrive at the edges of Earth's atmosphere — baked by solar radiation and deprived of liquid water, at Antarctic temperatures — researchers can study them to learn how a spacecraft-riding terrestrial microbe contaminate another extreme-but-liveable environment, such as the surface of Mars.

Of course, Baross wants to prevent such contamination. But humanity might someday want to live on Mars — and that process could very well start with adding terraforming bacteria to the planet.

Image: Indian Space Research Organization

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