Frosty Changes on Mars’s “Happy Face Crater” Has Made Its Grin Even Bigger

Given the year we’ve just given up, you don’t have to worry too much about being happy right now (we’ll ask for a break) but it didn’t stop at widening Cheshire Cat Green in Tuesday’s “Happy Face Crater”. The cheerful-looking crater is helping scientists track climate trends on the Red Planet, and once-melting snow is not a sign of bad news. The hole is located in the South Pole region of Mars, which is icy, but changes due to heat loss. A decade of documenting this feature means we now have a comparison of how much heat loss has occurred over the past decade.

NASA’s Mars Reconnaissance Orbiter 200 has been studying Mars since 2006. Its HiRISE (High-Resolution Imaging Science Experiment) instrument is the most powerful camera ever sent to another planet, regularly returning incredibly detailed images of Mars’ features to glaciers from ancient rivers as they happened. This first crater spread in 2011 because people like to see faces and recognizable things in unusual places, because the smiley feature was dubbed as Happy Face Crater. From gorillas and Muppets to Batman’s signals and (well, that’s pretty good) Mars is a true treasure trove for “spotting” unexpected items from one dragon to another. During the first of the same season, December 13, 2020, another image of the crater taken on December 1315 showed how much frost had been reduced as a result of the then heat loss as more parts of the red land were exposed. 

According to Ross Beyer, a member of the HiRISE team, “The ‘blobby’ properties of the polar caps are due to the sun’s removal of carbon dioxide in these circular formations.” Bliss is when a solid liquid bypasses the step and turns into a gas. Mars is a very cold planet due to its thin atmosphere and lack of moderate temperature from the ocean. In the Martian winter, carbon dioxide solidifies to form a thin layer of dry ice on the ground. When the sun shines on it, the ice melts, avoiding the liquid step and turning directly into steam, causing surface erosion.

As you can see in the image above, the “nose” in 2011 consisted of two rounds of depression. By 2020, these dips have grown in size and merged. Measuring these changes helps scientists understand the annual cycle of deposit and removal of polar frosts. Long observations provide insights into long-term climate trends on Mars. It is important to understand these climate trends in our search for human exploration and the possibility of Mars settling on another planet, determining whether or not Mars may have the appropriate conditions to support life.