Who has an even bigger smile than ten years ago? This crazy-looking crater on Mars.
These two images were taken by the HiRISE (High Resolution Imaging Science Experiment) camera aboard the Mars Reconnaissance Orbiter and show how the surface of Mars changes over time – in this case due to thermal erosion.
The first of these images was taken in 2011 and the second in December 2020, around the same season, and shows several different changes. There are color variations that are due to different amounts of bright frost over dark red earth, according to the HiRISE team.
You will also see that some of the “spot” characteristics have changed shape due to the heat of the sun causing sublimation – when the solid turns directly into a gas, bypassing the liquid phase. This thermal erosion has enlarged the “mouth” of the face, and the “nose” – consisting of two circular depressions in 2011, has already grown and merged.
MRO is one of NASA’s oldest and longest-running spacecraft. The mission launched in 2005, arrived on Mars in 2006 and has been observing Mars ever since. HiRISE is the most powerful camera ever sent to another planet and has provided many incredibly detailed images of the characteristics of Mars. Some of our favorites over the years have been in the process of avalanches, dark streams that may or may not be salt material penetrating the surface, images of our own spaceships and rovers on the surface of Mars, and much more.
But one of the main advantages of long-range spacecraft is the ability to observe changes in what is observed. The HiRISE team has been documenting this “smiling face” feature for more than a decade, which means we now have good comparisons on the surface of change, right before our eyes.
“Measuring these changes during the Martian year helps scientists understand the annual deposition and elimination of polar frost, and observing these places over long periods helps us understand the longer-term climate trends of the Red Planet,” wrote HiRISE co-researcher Ross. Beyer.
See more amazing images of Mars on the HiRISE website.