A University of Southern California scientist says that experiments done more than 20 years ago on Martian soil collected by Viking landers 1 and 2 show that life exists on Mars in the form of microbes. The significance of that finding was overlooked and the data was lost after NASA concluded that its experiments showed only signs of chemical activity on the surface of Mars, according to Joseph Miller, a USC neurobiologist. But a careful reexamination of a fragment of the recovered NASA record shows a surprising pattern: gas released by the Martian soil and tracked by Viking followed the same kind of rhythms followed by all Earth-bound organisms from humans to fruit flies. ?I think, basically, that it?s bugs," says Miller.
Two Viking spacecraft were launched by NASA in August and September of 1975 and took almost a year to reach Mars. Once there, both sent probes to the surface some 3,000 miles apart to conduct a series of experiments, several of which were designed to look for evidence of life. In one of those tests, a robotic arm scooped up soil samples, which were dropped into a dish along with a radioactive carbohydrate solution. Scientists reasoned that any organisms in the Martian soil would consume the nutrients and release radioactive carbon as a gas, something the probe was equipped to measure.
Viking found clear evidence that the Martian soil generated gas over the nine-week experiment, but scientists concluded that was the product of reactive chemical ?superperoxides? in the soil, not evidence of life. That closed the book on the Viking experiments until Miller, who had worked with NASA in the early 1980s studying the sleep cycles of monkeys in space, asked the agency to go back over the record of the experiment in 1999. ?I figured this was going to be on a website somewhere,? Miller says. ?Well, guess again. They had lost track of it.?
NASA scoured its archives and turned up the long-neglected computer tapes, only to discover they were coded ?in a format so old that the programmers who knew it had died,? says Miller. Working from a printed record that the initial NASA team had saved, Miller has been able to assemble and analyze about a third of the data and plans to present his initial findings at a scientific conference in San Diego. Miller found the gas emissions from the soil sample fell into a cycle of precisely 24.66 hours -- the length of the Martian day -- a pattern that was linked to a slight variation in the temperature inside the mostly insulated lander. That pattern of heightened activity in the warmer daytime and inactivity at night resembles the kind of temperature-driven circadian rhythm that simple terrestrial organisms such as bread molds exhibit.
Also, the amount of carbon gas released rose over the course of the experiment, but then also dropped sharply at one point when the soil sample was heated to 320 degrees Fahrenheit. ?I think that what was happening there was that we were killing all the bugs,? says Miller, who is working to recover the full Viking data record to see if it confirms the pattern. More recent studies have shown signs of climate change on Mars dating back about 100,000 years, instead of millions or billions, suggesting that there could be shallow ice reserves below the planet's surface -- a key to sustaining life there. Miller says he hopes his unexpected findings will encourage both NASA and European researchers to revive biological experiments in the next generation of Mars probes. ?Over the years NASA has primarily been interested in geology,? Miller says. ?But this is something out of the clear blue sky, or I guess I should say the red sky.?
Opinion: It has long been claimed by manned spaceflight scientists at NASA that the Jet Propulsion Laboratory's planetary exploration group has a bias against finding life in the solar system because they fear that this will divert budget to manned spaceflight and away from JPL.
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