Phoenix Mars Rover Dectects Red Snow

Finishing up its work on Mars before winter comes, Phoenix used its LIDAR instrument this week to detect snow forming in clouds high above its current location.

The instrument fires a laser toward the sky, and the beam is scattered off airborne particles—ice crystals, in this case. There are no signs as of yet that the snow actually makes it to the ground, however; it appears the snow is vaporized in midair.

Nonetheless, scientists are eagerly remaining vigilant in case any snow may make it all the way to the surface. “We’re going to be watching very closely over the next month for evidence that the snow is actually landing on the surface,” said York University’s Jim Whiteway, lead scientist for the lander’s weather station.

Any sign of water making it to the surface of the red planet would no doubt excite astrobiologists, who cling to hope—despite years of disappointments—that Mars may still harbor microbial life or signs of it.

In addition to the snow, Phoenix has detected frost, ground fog, and clouds, each occurring more frequently as the weather turns colder. The mission also detected subsurface ice (see More Ice on Mars?), which was considered news this summer.

There are no signs as of yet that the snow actually makes it to the ground, however; it appears the snow is vaporized in midair.

Also, NASA has interpreted certain geological finds on Mars—such as calcium carbonate and possible clays—as other signs of the presence of liquid water on Mars’s surface at some point in the past.

The University of Arizona’s Bill Boynton, lead scientist for the lander’s TEGA instrument, said, “Assuming we really do need liquid water to form these carbonates—which appears to be the case—then what this says is that we might have had standing water at some point in the past.” (Read more on that news at ScienceNOW.) These findings likewise excite evolutionary biologists in their quest for water (and life, as the evolutionary tale goes) on the planet. Of course, there is plenty of geological evidence for water in the history of Mars, but a dearth of evidence of life.

As for Phoenix, it will not be reborn after the winter. As Martian winter comes, Phoenix is receiving less and less sunlight and consequently less power for its solar batteries, even while it must expend more and more energy to warm its systems. By April of next year, the Sun will disappear completely in the Martian Arctic for three months, during which time frost will build up on the lander’s solar panels, leading to cracks and perhaps causing them to fall off. The temperature will eventually fall to -184˚F (-120˚C) and even colder. It almost brings an icy tear to our eyes, since the lander spawned four News to Note items (the weeks of June 7, July 5, August 2, and August 9) during its short life!