Is there life on Mars?
By Daniel J. McLaughlin
I bet you didn't get past the headline without singing the David Bowie classic to yourself. The 1971 hit has nothing to do with extraterrestrial life, summing up a "sensitive young girl's reaction to the media", according to the late artist. The song's narrator ponders the question "is there life on Mars?", and he was not alone with this curiosity.
Ever since Man looked up at the stars, he has wondered whether he is truly alone in this universe. As he started to explore space, discovering planets in the solar system, there were questions about whether life could be sustained. Mars is the fourth planet from the Sun, with an average distance of 225 million kilometres from Earth (ranging from 54.6 and 401 km, depending on their orbits).
With Earth busting with life, is there at least one life form on the Red Planet?
On July 30, 1976, Gil Levin was working from a NASA laboratory in California, monitoring data from NASA's Viking lander. It was, for the first time in history, conducting an experiment on the surface of Mars. He was closely watching a graph that was coming out a printer, and found a thin line measuring radioactive carbon edge upwards. He had seen this before. This had happened when he performed the test with microbes on Earth. This new data came from tens of millions of miles away, and could have been proof of microbiotic Martians.
Or it could be proof of microbiotic Earth life that was accidentally sent there. "It's a Faustian condition of space exploration that we cannot search for life on alien planets without bringing along very small amounts of very small Earth life," the New Yorker writes.
It was not the only experiment conducted on the surface at the time. There were three others that came back with varying results. As the data trickled back to Earth, it became clear that "carbon dioxide was released when organic compounds were added to Martian soul, though not when the mixture was superheated", according to science magazine Nautilus. This was a life signature. It was found in the first two experiments, including Gil Levin's, but the third came back with mixed results.
It was the fourth that added doubt. Employing a gas chromatograph and a mass spectrometer, a device that measures the size of molecules, the fourth experiment showed no signs of life - and more importantly, absolutely no organics on Mars. "Organics exist all over space - on asteroids, comets and meteors, and in interstellar dust," they explain. The experiment suggested that Mars' surface was poisonous or self-sterilising, and Viking had found "a barren, windblown red planet, pockmarked by craters, cold and dead as the moon".
How can NASA find life on Mars? Traditionally, it has followed the water. Since all organisms in Earth require it, and Earth organisms are the only ones they know, they seek extraterrestrial life by applying Earth logic. Recently, they have actually found liquid water on the surface of Mars. An orbiting spacecraft has detected what NASA scientists are calling recurring slope linae. In other words, cold, salty streaks of damp soil on the cold desert planet - they appear seasonally in several craters and chasms.
Is there life on Mars? Your guess is as good as mine, but we are drawing closer - albeit by baby steps - towards a definitive answer.