Thirty-four years after NASA’s Viking missions to Mars sent back results interpreted to mean there was no organic material — and consequently no life — on the planet, new research has concluded that organic material was found after all.
The finding does not bring scientists closer to discovering life on Mars, but it does suggest a greater likelihood that life exists, or once existed, there.
“We can now say . . . that the Viking organics experiment that didn’t find any (organic material) had most likely destroyed what was there during the testing,” said Rafael Navarro- Gonzalez of the National Autonomous University of Mexico.
The original 1976 finding of “no organics” was controversial from the start because organic matter — complex carbons with oxygen and hydrogen, which are the basis of life on Earth — is known to fall on planets all the time.
The new results flow directly from a discovery made by NASA’s Phoenix lander in 2008.
Mary Voytek, senior scientist for astrobiology at NASA, said the findings demonstrate the ever-present risk of reaching “false negatives” in space based on limitations of the equipment used and of the scientists’ understanding of conditions beyond Earth.
The new research found an unexpected and unusual compound to be widespread at its landing site on northern Mars.
The discovery of the highly reactive chemical perchlorate led NASA’s Christopher McKay, an astrobiologist at the Ames Research Center, and Navarro-Gonzalez to test whether the perchlorate had skewed the Viking results that showed no sign of organic material on Mars.
They combined magnesium perchlorate with soil from Earth’s most Mars-like environment — Chile’s Atacama Desert — and heated the sample in the way it was heated by Viking instruments on Mars.
They found that the small amount of organic material known to be in the Atacama soil was detectable when mixed with the perchlorate at low temperatures but was broken up into water and carbon dioxide when heated alongside the perchlorate.
The missions
Viking 1 and Viking 2 were launched in 1975 and arrived at Mars in the summer of 1976. Each had an orbiter and a lander. They took photos of the surface of Mars and tested the atmosphere and surface in a search for evidence of life. Source: nasa.gov; photo of Mars’ Utopian Planitia: NASA
