Chalk another discovery up to the Mars Phoenix Lander. Several months after finding water ice beneath the Martian soil, the NASA robot has now turned its gaze upward to the sky, and has observed a light snowfall over the polar region. Scientists said the discovery of snow on Mars was made by an instrument that shined a laser into clouds about two miles above the ground, revealing the presence of ice crystals. “Nothing like this has ever been seen on Mars,” said [scientist] Jim Whiteway [Los Angeles Times].
The ice crystals quickly vaporized as they fell through the atmosphere of Mars, but researchers say they’ll be watching during the next two months to see if the snow ever reaches the ground. Over the past few months, as the Martian winter has moved in, Phoenix has also observed frost, ground fog, and clouds of ice crystals.
In another recent experiment, Phoenix examined the composition of the Martian soil and confirmed the presence of calcium carbonates, common clays found in wet environments on Earth…. [T]he presence of carbonates suggests that water was a dominant force in Mars’s early chemistry [National Geographic News]. However, the Phoenix hasn’t yet succeeded in its search for the complex organic molecules that would indicate that the planet was once habitable for microbes.
The Phoenix’s mission is now winding down. Before the end of October, [engineer Barry] Goldstein said, there won’t be enough power left to keep the lander’s robotic arm operating, so digging into the soil and scraping ice samples from beneath the soil will have to stop. By November, Phoenix will be standing rigidly in the pitch dark, and carbon dioxide in the atmosphere will encase it in ice like some otherworldly frozen mummy – at more than 150 degrees below zero Fahrenheit [San Francisco Chronicle]. While the Phoenix has a “Lazarus” program that will send a signal to Earth if its solar panels reactivate after the harsh winter, the lander’s engineers say the chance of a resurrection is extremely slim.
Image: NASA/JPL-Caltech/University of Arizona/Canadian Space Agency
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