Still, understanding how well microbes can survive in space is of importance when sending out orbiters or landers around bodies that might present the right conditions for life, such as Mars. Scientists want to be careful to avoid contaminating other worlds with life from our own. And microbes' resilience to outer space enhances the prospects of panspermia, in which life can be seeded between planets via meteors and other traveling bodies.
This basis formed part of the rationale for a study led by Rocco Mancinelli, a senior research scientist at the Bay Area Environmental Research Institute, a nonprofit space and atmospheric science research group.
"Results from of this study are relevant to understanding the adaptation and evolution of life," Mancinelli wrote in an e-mail to Astrobiology Magazine.
In his experiment, Manicelli took pure cultures of two salt-loving microbes, Halorubrum chaoviator and Synechococcus nägelli, from solid salt crusts and grew them. After drying them, some of the samples were sent to the International Space Station's external platform space exposure facility, called EXPOSE-R. Those microbes remained on the exterior for nearly two years. Other microbes were held back on Earth as control samples.
Surprisingly, some of those in space survived, Mancinelli said.
"Those organisms that were exposed to only the space vacuum all survived. Those exposed to high doses of ultraviolet radiation died, those exposed to lower doses of UV showed some survival," he said.
That said, the typical time to move between the planets is millions of years, making the result "irrelevant" if they were SNCs, Mancinelli said. Microbes could, however, survive in meteorites with a transit time of a few years, providing they are shielded from UV radiation.
http://static.ddmcdn.com/gif/moon-microbes-670x440-150604.jpg
No comments:
Post a Comment