Register for an account

X

Enter your name and email address below.

Your email address is used to log in and will not be shared or sold. Read our privacy policy.

X

Website access code

Enter your access code into the form field below.

If you are a Zinio, Nook, Kindle, Apple, or Google Play subscriber, you can enter your website access code to gain subscriber access. Your website access code is located in the upper right corner of the Table of Contents page of your digital edition.

The Sciences

Another awesome Martian avalanche

Newsletter

Sign up for our email newsletter for the latest science news

Spring is approaching us here in the northern hemisphere on Earth once again, and we are experiencing the annual thaw of the winter ice. Spring is approaching the northern hemisphere of Mars as well, and with it comes the thaw of carbon dioxide ice. Some of that dry ice sits at the tops of cliffs, and when it thaws it dislodges the material there. The rock and debris on Mars then does the same thing it would do on Earth: it falls. Fast. And when it does, you get this slice of Martian awesomeness:

HiRISE_avalanche_March2010.jpg

Holy scarp! That's another avalanche on Mars caught in the act by the HiRISE camera on Mars Reconnaissance Orbiter. I say another, because a few others have been seen, including this spectacular one two years ago, and lots of older ones that left their marks on the Red Planet's surface. This one is amazing! You can see the debris falling down the cliff's edge (the top of the cliff is to the bottom left of the image, and we're looking almost straight down the cliff's face) and then creating a plume of dust at the bottom, hundreds of meters below. When HiRISE took this image, the slide couldn't have been more than a minute old. If you look at the higher-res image (click the image above to embiggen) you can see that there have been a lot of avalanches here in the past, too. The bottom of the cliff has lots of material clearly deposited by fast-moving falling debris. To be honest, it's not completely sure that the sublimation (the change from solid directly to gas) of carbon dioxide is causing these avalanches, but it does seem the most likely explanation. Whether it's dry ice or not, what this shows us directly is that Mars is still an active place. Certainly the surface is undergoing continual (if small scale) modification, with avalanches, meteor strikes, and other processes still occurring even, literally, today. Mars is a very, very cool place. If you want to learn more, check out the HiRISE blog, which always has great stuff, including explanations of these extraterrestrial rockslides. And when you read about Mars and our exploration of it, remember this: it is an entire world, worthy of our attempts to understand it. And that is one of the grandest things we humans ever do.

2 Free Articles Left

Want it all? Get unlimited access when you subscribe.

Subscribe

Already a subscriber? Register or Log In

Want unlimited access?

Subscribe today and save 70%

Subscribe

Already a subscriber? Register or Log In