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Let It Snow [on Mars]

NASA’s Phoenix Mars Lander has seen snow falling on the red planet!

One of the probe’s atmospheric instruments detected ice crystals coming from clouds about 2.5 miles (4 kilometers ) above, although the flakes seem to have vaporized before they reached the ground.


—Image courtesy NASA/JPL-Caltech/University of Arizona/Canadian Space Agency

This probably isn’t a huge surprise, as we already knew Mars has glaciers and ice caps that grow and retreat with the seasons, so it was a good bet it still has a hydrological cycle of some sort. Still, way cool to be potentially seeing it in action.

NatGeo News reporter Anne Minard has the full scoop, including other data from Phoenix that bolster Mars’s likely history as a wet and wild world.

The news got me to thinking: Which other bodies in our solar system have snowfall?

After a quick roll around teh Internets, it seems the answer depends on how one defines “snow.”

In 1995 researchers found evidence that scorching hot Venus has a dusting of snow on its highland mountains. A 2004 study suggested that this venusian powder is made not of water ice but of lead and bismuth sulfides.

And well before Phoenix’s arrival, research had indicated that parts of Mars might have hydrogen peroxide snow created by swirling dust devils.

Up near the poles, the recently seen Martian snow seems to be made of water ice, although carbon-dioxide snow may be a possibility when winter gets in full gear.


The lander’s location near the north polar ice cap in an image by the Mars Global Surveyor

—Image courtesy NASA

The gas giants—Jupiter, Saturn, Uranus, and Neptune—don’t exactly have much in the way of surfaces for snow to fall on.

But Galileo spacecraft images from 2001 show that Jupiter’s moon Io, famous for its massive volcanism, has snows of sulfur dioxide created when gases condense from its erupting plumes as they shoot material high into the thin, cold atmosphere.

So far I’m not finding many candidates to host the 2278 Winter Olympics. Anyone know of any other snowy bodies that I’m missing? Drop me a note!