martes, 2 de noviembre de 2010
Life on Mars Could Stem From Earth
* Scientists are developing a detector to identify and classify DNA and RNA found on Mars.
* They suspect any Martian life, if it exists, is related to Earth life.
* Simulations and experiments show microbes can survive the radioactive environment of space.
Martian DNA could remain viable for about one million years or so underground. Click to enlarge this image.
A team of scientists suspects that if there is life on Mars, it may look familiar.
"We think that if there is life on Mars, it could be related to us," Massachusetts Institute of Technology engineer and scientist Christopher Carr told Discovery News.
With NASA funding, Carr and colleagues at MIT are developing a prototype device to decode alien DNA, a project known as the Search for Extraterrestrial Genomes (SETG). They hope to fly an instrument as part of a joint NASA-European Space Agency mission to Mars slated to launch in 2018.
Working with subsurface ice, brine or soil samples, SETG would attempt to isolate, amplify, detect and identify nucleic acids -- right there on Mars.
"If the DNA or RNA is as we know it, then we should be able to detect it with this instrument," Carr said.
He estimates Martian DNA could remain viable for about one million years or so underground, where it would be shielded from the harsh ultraviolet rays and space radiation that sterilize the planet's surface.
"Everybody expects there to be organics on Mars. There might have been life on Mars. There might be evidence of that stuff preserved if you go to the right places," said Cornell University planetary scientist Steve Squyres at a NASA astrobiology conference in October.
"The problem is that there are processes at work on Mars that destroy organic materials," he added. "If you want to have a fighting chance of getting to material that has been unaffected by these processes, it's good to go down."
The idea of looking for transplanted life stemmed from studies of meteorites from Mars that landed on Earth. Mars and Earth have swapped about a billion tons of rock over the years, Carr says, and experiments show that some hitch-hiking microbes can survive the journey.
Admittedly, the quest is a bit like looking for lost keys where the light shines, rather than in the darkness. However, Carr says there's good logic behind that philosophy when it comes to life on Mars.
"We would feel awfully silly if we spent a lot of time looking for something that was very different and didn't spend time looking for something that was very similar," Carr said. "Life could have arisen independently, but that is not the most likely scenario."
The scientists are concentrating on genes that are fairly ubiquitous in life on Earth. It will take another two years to refine SETG technology before it's ready for field tests in Chile's Atacama Desert or the dry valleys of Antarctica -- both of which resemble the cold, dry deserts of Mars.
Carr presented his team's project at a NASA workshop about applications of synthetic biology in space exploration, held at the Ames Research Center in California Oct. 30-31.