NASA's Mars Recognition Orbiter (MRO) spotted a deep well, approximately 180 meters in diameter, during its expedition around the planet.
The images were originally captured on January 24th by the equipment's HiRise camera and showed a kind of black spot.
For a better analysis, researchers at the University of Arizona had to adjust the brightness of the photos when they were taken by surprise. “The well's floor appears to be smooth sand and goes down to the southeast”, wrote NASA geophysicist Ross Beyer.
After discovering the well, the researchers will analyze whether it may be connected to other tunnels that would have been left behind by fast flowing lava channels. These tunnel networks exist on Earth, in places like Hawaii's Volcanoes National Park.
"The hope was to determine whether this was an isolated well or whether it was a skylight in a tunnel, much like skylights in Hawaii's lava tubes," said Beyer.
The hypothesis that ancient volcanoes may have left large cavernous lava tubes on the surface of Mars is an old one. Some scientists even defend that they may be large enough to house planetary bases in a possible human colonization of the Red Planet.
It's not the first hole
The discovery of this well is not the first of a hole of this magnitude. In 2012, the MRO found some other holes that resembled a 225-meter-high cave chain.
But to be sure what it is about, NASA needs to better develop its drone technology that can fly on Mars, because a rover like Perseverance, for example, it would be unusable if it fell into a hole like that.
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