Category Archives: Mars

dust devils, HiRise, Mars, Mars Reconnaissance Orbiter

It’s Windy on Mars!

Leave a comment

Dust Devils Just Keep on Dancing Across Mars

Okay, a few weeks ago we had a week’s worth of high winds where I live, typical for Colorado in the late winter.  We call ’em Chinook winds, and they tend to dry things out as they blow at speeds upwards of 70 to 90 mph (112-144 km/hour) and gusts up above 100 (160 km/hr).  That’s all part of a weather pattern that occurs here, and in other parts of the world as the seasons change.  Right now, as we saw in Texas a few days ago, the winds and the associated weather patterns whip up twisters, tornadoes, dust devils.

The winds blow on Mars, too, and the Mars Reconnaissance Orbiter’s High Resolution Imaging Science Experiment (HiRISE) camera has been very good at spying out Martian dust devils.  Unlike a tornado which we see here on Earth, a dust devil typically forms on a clear day when the ground gets heated by the Sun. That warms the air just above the ground, and that air rises quickly through a small pocket of cooler air above it. If the conditions are just right, the air can start to rotate, and as it does, it picks up dust.  This is a  frequent occurrence on Mars.

HiRise view of a dust devil on Mars, taken March 14, 2012. Courtesy NASA/HiRise Team.

On March 14th, HiRISE caught sight of a Martian dust devil roughly 12 miles high (20 kilometers) whirling through a region called Amazonis Planitia.   The dust devil about (70 yards, or just about 70 meters across). The image was taken during late northern spring, two weeks short of the northern summer solstice, a time when the ground in the northern mid-latitudes heats up in the sunlight.

One of the cool things about these dust devils is that they scour the ground of dust, leaving behind a thin, sinuous little path. When those little paths were discovered, their appearance and cause was unknown. It didn’t take long for scientists to connect them with the appearances of dust devils. It appears that these dust devils are one mechanism by which dust gets redistributed around the Martian surface.

Check out the full story and a very cool animation showing what the dust devil might look like from the side at the NASA Mars Reconnaissance Orbiter page. It’s full of wooty Mars goodness!  And, if you experience winds and dust devils where YOU live on Earth, then you have a good idea of what it’s like on Mars when one goes twisting by!

 

 

'Casts, Jupiter, Mars, planets, saturn, venus

Bright Lights in the Sky

Leave a comment

No UFOs Here

The post-sunset view on March 11, planets Venus and Jupiter. Click for a larger view.

Unless you’ve been buried under a blanket of clouds the past few weeks, you’ve probably noticed some bright lights in the western sky just after sunset.  Aside from the Moon (and you know what that looks like, don’t you?), you might be wondering what they are.  Well, if they’re not moving rapidly (like changing position over the space of a few minutes, as aircraft would do), then what you’re seeing are the planets Venus and Jupiter.  Here’s tonight’s view of the pair, well after sunset. You won’t see Mercury (too close to the Sun), but you can’t fail to notice how dazzling the two planets appear these early springish nights.

If you have binoculars or a small telescope, check out Jupiter. You might be able to see its four largest moons. They’ll look like little pinpoints of light on either side of Jupiter.

Mars is just below Leo, and Saturn and Spica rise together later in the evening. Click to ensaturnate.

 

The next couple of nights, these two planets snuggle up really close together in the western sky.   Once you’ve found them, and turn toward the east and look for Mars snuggled up underneath the constellation, Leo the Lion.  An hour or two later, you should be able to find Saturn just rising in the East. It’s a planet spectacular!

Of course, there are a lot of other things to look at in the sky this month, so don’t run back inside after you’ve seen the planet.  Dress warmly (if it’s cold where you are), and explore that sky!  There’s a lot to be found.

By the way, check out “Our Night Sky” at Astrocast.TV for a short program I did on what’s up this month.  It’s free to embed on observatory and planetarium Web sites (with proper credit, of course), so check it out!