An experiment to find signs of ancient life on mars

By Paul Voosen Feb. Tucked in the rover's belly are nine stainless steel thimbles, each filled with solvent, that are the mission's best shot for detecting signs of ancient martian life. Now, well into its fifth year on Mars, the rover has reached a mountain thought to be a promising hunting ground, and mission scientists are ready to dump freshly drilled dirt into one of their precious wet chemistry cups.

An experiment to find signs of ancient life on mars

Did year-old Viking experiment discover life on Mars? October 21, by Lisa Zyga, Phys. This image was taken by Viking 2 in Perhaps most intriguingly, they also performed experiments that searched for signs of microbial life in Martian soil. Overall, these life-detection experiments produced surprising and contradictory results.

One experiment, the Labeled Release LR experiment, showed that the Martian soil tested positive for metabolism—a sign that, on Earth, would almost certainly suggest the presence of life.

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However, a related experiment found no trace of organic material, suggesting the absence of life. With no organic substances, what could be, or seem to be, metabolizing? In the forty years since these experiments, scientists have been unable to reconcile the conflicting results, and the general consensus is that the Viking landers found no conclusive evidence of life on Mars.

However, a small minority of scientists argues that the Viking results were positive for life on Mars. At first, Levin thought that the LR results were unclear, and stated merely that the results were consistent with biology.

However, inafter many years of further experiments on Earth, along with new discoveries on Mars which NASA has now declared "habitable"and the discovery of microorganisms living under conditions on Earth as severe as those on Mars, he and his Viking Co-Experimenter, Dr.

Straat, have argued that the Mars results are best explained by living organisms.

An experiment to find signs of ancient life on mars

Recently, Levin and Straat published a perspective piece in the journal Astrobiology in which they reconsider the results of the Viking LR experiment in light of recent findings on Mars and recent proposals for inorganic substances that may mimic the observed metabolism-like processes.

They argue that none of the proposed abiotic substances sufficiently explains the Viking results, and that Martian microbes should still be considered as the best explanation of the results.

How the Labeled Release experiment worked In the LR experiment, both the Viking 1 and Viking 2 landers collected samples of Martian soil, injected them with a drop of dilute nutrient solution, and then monitored the air above the soil for signs of metabolic byproducts.

Since the nutrients were tagged with radioactive carbon, if microorganisms in the soil metabolized the nutrients, they would be expected to produce radioactive byproducts, such as radioactive carbon dioxide or methane. Before launching the Viking spacecraft, the researchers tested the experimental protocol on a wide variety of terrestrial soils from harsh environments, from Death Valley to Antarctica.

In each case, the experiments tested positive for life. In each case, the experiments now tested negative. To further confirm that the experimental procedure would not produce false positives, the researchers tested it on soils known to be sterile, such as those from the Moon and the Surtsey volcanic island near Iceland, which produced negative results as expected.

Once on Mars, the LR experiment was performed after the experiment searching for organic molecules came up empty-handed. So it came as a surprise when both Viking landers, located 4, miles apart, collected soil that tested positive for metabolism.

To rule out the possibility that the strong ultraviolet radiation on Mars might be causing the positive results, the landers collected soil buried underneath a rock, which again tested positive.

Levin and Straat believe that these results provide some of the strongest evidence that the soil contained Martian life. Nonbiological candidates Ever since the LR experiments, researchers have been searching for other kinds of nonbiological chemicals that might produce identical results.

In their new paper, Levin and Straat review some of these proposals. One possible candidate is formate, which is a component of formic acid found naturally on Earth. A LR-type experiment found that formate in a soil sample from the Atacama Desert in South America produced a positive result, even though the soil contained virtually no microorganisms.

Another potential candidate is perchlorate or one of its breakdown products. Inthe Phoenix mission to Mars detected perchlorates in the Martian soil.NASA has picked an ancient river delta as the landing site for its uncrewed Mars rover, to hunt for evidence of past life on Earth's neighboring planet, officials said Monday.

Mars rover steps up hunt for molecular signs of life. that are the mission's best shot for detecting signs of ancient martian life. Now, well into its fifth year on Mars, the rover has reached. A fresh look at NASA data suggests that a robotic mission uncovered microbial life on Mars—more than 30 years ago.

the LR experiment came out positive for life, and the control experiments. Mars rover steps up hunt for molecular signs of life. that are the mission's best shot for detecting signs of ancient martian life.

Now, well into its fifth year on Mars, the rover has reached. Did year-old Viking experiment discover life on Mars? In the NASA Viking landers took samples of soil on Mars and tested them for signs of organic carbon.

Those are ancient of. Jun 07,  · Watch video · "The question of whether life might have originated or existed on Mars is a lot more opportune now that we know that organic molecules were present on its surface at .

Life on Mars: Exploration & Evidence