martian anniversary

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Forty years ago, we landed on Mars… and found life?

“The team held their breath as the control experiment was performed, and this is where things get fishy. Subsequent injections of radioactive nutrients failed to produce any response; what we were seeing was consistent with either organic or purely chemical, inorganic processes. Perhaps there wasn’t life on Mars, after all. Despite the initial declaration — that if any of the three tests came back positive, we’d announce life on Mars — these results seemed to be inconclusive. In the forty years since, we’ve never replicated the experiment, and we still don’t know for certain.”

On July 20, 1976, the Viking 1 lander touched down onto the Martian surface, followed just a few weeks later by Viking 2. On board both landers were a suite of three experiments designed to look for signs of life. While the Gas Chromatograph-Mass Spectrometer and the Gas Exchange experiment both came back negative, the Labeled Release experiment — where nutrient-rich molecules tagged with radioactive carbon-14 were added to the Martian soil — gave off a positive release of radioactive CO2. Did our first trip to Mars really find life after all?

Martian Anniversary Selfie

Image Credit: NASA, JPL-Caltech, MSSS

Explanation: June 24th marked the first full Martian year of the Curiosity Rover’s exploration of the surface of the Red Planet. That’s 687 Earth days or 669 sols since its landing on August 5, 2012. To celebrate, consider this self-portrait of the car-sized robot posing next to a rocky outcrop dubbed Windjana, its recent drilling and sampling site. The mosaicked selfie was constructed with frames taken this April and May using the rover’s Mars Hand Lens Imager (MAHLI), intended for close-up work and mounted at the end of the rover’s robotic arm. The MAHLI frames used exclude sections that show the arm itself and so MAHLI and the robotic arm are not seen. Famous for panoramic views, the rover’s Mastcam is visible though, on top of the tall mast staring toward the left and down at the drill hole.