Humans love to give fitting nicknames to formations out in space, whether it's theor the . You can see exactly why the "Happy Face Crater" on Mars got its unofficial moniker. It seems to be quite pleased that it's helping scientists track climate trends over time on the red planet.
The crater is located in the region of Mars' south pole. That's a frosty place, but it isn't frozen in time. The landscape shifts in appearance, as seen by the differences in images taken by NASA's Mars Reconnaissance Orbiter in 2011 and 2020.
The difference is in the amount of frost covering the ground. "The 'blobby' features in the polar cap are due to the sun sublimating away the carbon dioxide into these round patterns," wrote MRO HiRise camera team member Ross Beyer in a statement Thursday. "You can see how nine years of this thermal erosion have made the 'mouth' of the face larger." Sublimation happens when a solid turns into a gas.
The face's nose has also transformed, from two distinct circles into one blob. The Mars Reconnaissance Orbiter monitors seasonal changes, but this sort of observation across nearly a decade of time "helps us understand longer term climate trends on the red planet," said Beyer.
The MRO has been in orbit around Mars since 2006. The spacecraft's HiRise camera and its science team at the University of Arizona have witnessed all sorts of Martian wonders, fromto an .
The Happy Face Crater is in good company. Last year, the MRO found an impact crater that looked like the.