Life on Mars Found by NASA's Viking Mission?

New analysis suggests robots discovered microbes in 1976.

In 1976 NASA sent two space probes, Vikings 1 and 2, to Mars to determine whether life exists on the red planet. The probes carried three experiments specially designed for the task, one of which was called the Labeled Release (LR) apparatus.

The LR experiment worked by scooping up a bit of Martian soil and mixing it with a drop of water that contained nutrients and radioactive carbon atoms.

(Related: "Mars Soil Resembles Veggie-Garden Dirt, Lander Finds.")

The idea was that if the soil contained microbes, the life-forms would metabolize the nutrients and release either radioactive carbon dioxide or methane gas, which could be measured by a radiation detector on the probe.

A number of control experiments were also performed, including heating

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