It’s storm season in the northern hemisphere of Mars -- a time when frontal boundaries sweep across the landscape, often stirring up boiling clouds of dust.
A recent study counted more than 300 frontal systems barreling across the planet in one Mars year. Most of them were in the northern hemisphere, during spring and summer. Most lasted a day or two, and stretched across hundreds of miles.
And summer is just getting started in the northern hemisphere, so it’s time for more of these systems. They begin as parts of the polar ice cap vaporize, releasing carbon dioxide and water vapor into the atmosphere. These gushers of gas then move across the high northern plains.
Sometimes, the fronts stir up the powdery Martian dust, creating small dust storms. The dust warms the air, which helps keep the system going while raising more dust.
Some dust storms can grow to gigantic proportions, with the biggest covering almost the entire planet. Most of the really big storms, though, begin in the southern hemisphere. It’s winter there now, so storms are rare.
It’s possible that some of the storms could create lightning, as the dust grains build up an electrical charge as they move through the sky. A study a couple of years ago found evidence of lightning in radio waves from the planet. But other studies have come up empty.
With lightning or without, though, the fronts bring a bit of activity to the normally quiet surface of Mars.
Script by Damond Benningfield, Copyright 2012
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