01.06.2017 Earth and Its Moon, as Seen From Mars
11.15.2016 Schiaparelli Impact Site on Mars, Stereo
11.03.2016 Schiaparelli Impact Site on Mars, in Color
03.30.2016 Erisa Hines
03.30.2016 Buzz Aldrin
03.21.2016 For a Decade Orbiting Mars: One Recent View
03.09.2016 For a Decade Orbiting Mars: One Recent View
03.09.2016 Mars Reconnaissance Orbiter By the Numbers
03.01.2016 MRO sees Frosty Spring Slopes
02.12.2016 Women in Science
02.10.2016 Wind at Work
11.16.2015 Change Observed in Martian Sand Dune
10.05.2015 'The Martian' Story's Ares 4 Landing Site
10.05.2015 The Ares 3 Landing Site (Figure A)
09.30.2015 Avalanche Ho!
06.29.2015 Mars Exploration Zone Layout Considerations
06.17.2015 Active High-Latitude Dune Gullies
06.03.2015 Crisp Crater in Sirenum Fossae
05.20.2015 Sedimentary Rock Layers on a Crater Floor
05.20.2015 Honey, I Shrunk the Mesas
05.11.2015 Icy Wonderland
05.04.2015 Diverse Orbits Around Mars
03.27.2015 South Pole Spiders
03.27.2015 A Smile a Day....
03.25.2015 Pitted Landforms in Southern Hellas Planitia
03.12.2015 Curiosity Heading Away from 'Pahrump Hills'
02.18.2015 Lava Flow Near the Base of Olympus Mons
02.09.2015 Yardangs in Arsinoes Chaos, Mars
02.04.2015 Curiosity Rover at 'Pahrump Hills'
01.22.2015 Frost on Crater Slope
01.16.2015 Components of Beagle 2 Flight System on Mars
12.03.2014 An Enigmatic Feature in Athabasca Lava Flows
12.02.2014 NASA's Journey to Mars
11.07.2014 Mars Orbiter Sizes Up Passing Comet
10.19.2014 Siding Spring Mars Spacecraft
Dry Ice Gone WildHave you ever played with dry ice (with leather gloves on of course!)? Perhaps you've made Halloween punch? Set a spooky scene? The fun comes from the fact that dry ice goes directly from solid to vapor, unlike water ice which melts into liquid when it gets warm.
On Mars the seasonal polar caps are composed of dry ice (carbon dioxide). In the springtime as the sun shines on the ice, it turns from solid to gas and causes erosion of the surface. I enjoy the incredible diversity of forms that the erosion takes, and am studying the factors that give us "spiders", "caterpillars", or "starbursts", all colloquial words for what we rigorously name "araneiform" terrain.
This particular example shows eroded channels filled with bright ice, in contrast to the muted red of the underlying ground. In the summer the ice will disappear into the atmosphere, and we will see just the channels of ghostly spiders carved in the surface. This is truly Martian terrain - this type of erosion does not take place anywhere naturally on earth because our climate is too warm.
This image was taken with the High Resolution Imaging Science Experiment (HiRISE) camera on the Mars Reconnaissance Orbiter on Jan. 12, 2011.
Image Credit: NASA/JPL-Caltech/University of Arizona