A JPL-managed orbiter has found entrances to seven possible caves on the slopes of a Martian volcano, fueling interest in potential underground “habitats” and sparking searches for caverns elsewhere on the red planet, NASA reported Friday. Very dark, nearly circular features ranging in diameter from about 328 to 820 feet puzzled researchers who found them in images taken by NASA’s Mars Odyssey and Mars Global Surveyor orbiters. Using Mars Odyssey’s infrared camera to check the daytime and nighttime temperatures of the circles, scientists concluded that they could be “windows” into underground spaces, NASA reported. A report of the discovery of the possible cave skylights by Glen Cushing of the U.S. Geological Survey’s Astrogeology Team and his co-authors was published online by the journal Geophysical Research Letters. “Whether these are just deep vertical shafts or openings into spacious caverns, they are entries to the subsurface of Mars,” said co-author Tim Titus. “Somewhere on Mars, caves might provide a protected niche for past or current life, or shelter for humans in the future.” The discovered holes, dubbed “Seven Sisters,” are at some of the highest altitudes on the planet, on a volcano named Arsia Mons near Mars’ tallest mountain. – City News Service 160Want local news?Sign up for the Localist and stay informed Something went wrong. Please try again.subscribeCongratulations! You’re all set!