Carbon-rich organic molecules,
which serve as the building blocks of life, may be present on Mars after all,
say scientists – challenging a widely-held notion of the Red Planet as barren.
When Nasa’s two Viking Landers
picked up and examined samples of Martian soil in 1976, scientists found no
evidence for carbon-rich molecules or biology.
But after the Phoenix Mars Lander
discovered the chlorine-containing chemical perchlorate in the planet’s
“arctic” region in 2008, scientists decided to re-visit the issue.
This doesn’t say anything about the
question of whether or not life has existed on Mars”
End Quote Chris McKay Nasa’s Ames
They travelled to the Atacama
Desert in Chile, where conditions are believed to be similar to those on Mars.
After mixing the soil with
perchlorate and heating it, they found that the gases produced were carbon
dioxide and traces of chloromethane and dichloromethane – just like the gases
released by the chemical reactions after the Viking Landers heated the Martian
soil more than three decades ago.
They also found that chemical
reactions effectively destroyed all organic compounds in the soil.
“Our results suggest that not
only organics, but also perchlorate, may have been present in the soil at both
Viking landing sites,” said the study’s lead author, Rafael
Navarro-González of the National Autonomous University of Mexico, Mexico City.
But despite the excitement about
the finding, the researchers warn it is too early to conclude that the Red
Planet has ever had life.