Atacama Desert has "Mars-like" soil
DB: This is Earth and Sky. The Viking spacecraft landed on the surface of Mars in 1976.
JB: Its instruments scooped up soil samples and analyzed them for signs of life, but they found no evidence of organic compounds. Now, almost 30 years later, NASA scientists are scooping up soil in Chili’s Atacama Desert – a place that gets no rain, not even any fog. Its soil is the driest, most lifeless soil on Earth. That’s what gives it our planet’s nearest analog to the soil on Mars, according to Chris McKay at NASA’s Ames Research Center.
Chris McKay: There are organics in the soil in the Atacama, even in the driest region. But if Viking had landed there, it would not have detected those organics, because its instruments are not as capable as those that we would carry down to the field with us now…
DB: Another inhospitable feature of this Atacama soil is that it contains a chemical oxidant – a substance that decomposes organic matter – think of bleach or hydrogen peroxide.
Chris McKay: It’s this double whammy of not being able to grow, because there’s no water, and having to fight off this oxidant which is there in the soil… We think the same conditions would apply on Mars.
JB: And for today, that’s our show. Special thanks to
The image at left is Chili’s Atacama desert as seen from space. (NASA) Twenty–five years ago, on July 20, 1976, Viking soft–landed on the surface of Mars, becoming the first U.S. spacecraft to land successfully on the surface of another planet. Read Earth & Sky’s radio show about looking for life on Mars, or check out NASA’s web site on its Mars Exploration Program. Chris McKay told Earth & Sky: Our thanks to:
“When we say that the Atacama soil is ‘Mars–like,’ we really mean like the soils measured at the two Viking sites. The question is, how typical of Mars are those two Viking sites? Our guess is that it’s probably typical of the soils in the equatorial and mid–latitude regions. But near the ice–rich polar regions, things might be very different.”
Chris McKay
Space Science Division
NASA Ames Research Center
