Who has an even bigger smile than ten years ago? The silly crater for this sight on Mars.
Both of these images were taken by a HiRISE (High Resolution Imaging Science) camera aboard Mars ‘orbit and show how Mars’ surface changes over time – in this case, due to thermal abrasion.
The first of these photos was taken in 2011 and the second in December 2020, around the same season, and shows some different changes. According to the HiRISE team there are color variations resulting from different amounts of light frost on darker soils.
You will also see some of the “blistered” properties change shape due to the sun’s heat causing sublimation – when a solid directly turns into a gas, bypassing the liquid phase.
This thermal abrasion has enlarged the “mouth” face, and the “nose” – which was made up of two circular sockets in 2011 – has grown and merged now.
MRO is one of NASA’s oldest and longest spacecraft. The mission launched in 2005, reached Mars in 2006 and has been tracking Mars ever since. HiRISE is the most powerful camera ever sent to another planet, and it has provided a wealth of stunningly detailed images of Mars’ features. .
Some of our favorites over the years have been avalanches, dark currents that may be shiny materials or may not seep to the surface, images of our own spacecraft and cruising across Mars, and many others.
But major benefits of long-range spacecraft are the ability to track changes in buoys. The HiRISE team has been documenting the “Smiley Face” feature for over a decade, which means we now have good side-by-side comparisons of surface changes, right before our eyes.
“Measuring these changes throughout the military year helps scientists understand the deposition and sleep of polar frosts, and tracking these sites over long periods helps us understand the longer-term climatic trends in the Red Star,” wrote HiRISE research partner Ross Beyer.