Photographed in 2011 by the HiRISE instrument on the Mars Reconnaissance orbiter, a mysterious hole measuring 35 meters in diameter on Pavonis Mons, a large shield volcano in the Tharsis region, has left scientists scratching their heads. The cave below is approximately 20 meters deep and likely used to be 90 meters deep before collapsing and filling. This geological feature is a puzzle that awaits future exploration by spacecraft, robots, and astronauts.
The cause of this hole remains unknown as caves of this size on Earth are usually formed through the dissolution of limestone by water. However, Mars lacks carbonate rocks like limestone and has very little water. Therefore, another explanation must be sought for this unusual feature on Mars.
One possible explanation is that it led to a lava tube. Lava tubes form when the top layer of a lava flow hardens above ground while the lava continues to flow underground in a pipe-like structure. The collapse of sections of the roof can create holes like this one as seen in orbital images. These types of holes are of interest to NASA as they provide potential sheltered locations for Martian life that could withstand the harsh surface conditions.
Future exploration plans involve using spacecraft, robots, and astronauts to investigate further into this geological mystery on Mars.
