ROBERTO OROSEI

Roberto Orosei RADAR SCIENTIST, UNIVERSITY OF BOLOGNA; CO-INVESTIGATOR OF THE MARSIS INSTRUMENT ABOARD THE MARS EXPRESS SPACECRAFT

Roberto Orosei knew as early as 2008 that he’d found something exciting bouncing off the surface of Mars: bright radar “reflections,” spanning about 12 miles across, roughly a mile below the planet’s southern polar cap. The most plausible explanation was an underground lake of some sort, a potential harbor for extraterrestrial life. But Orosei wanted to make sure, which took almost a decade. Martian polar caps are more complicated, geologically and chemically, than Earth’s, containing rocks and thin layers of dust mixed with ice made of water and CO2, all of which can produce misleading radar readings. He and his team set out to knock down their own findings, developing a computer model to compute all the possible reasons for what they were seeing. “We wanted to leave no possibility unexplained,” he says. After running all the scenarios, they felt positive that the bright reflection they detected could only be something out of the ordinary: a shallow lake of briny water that remains liquid well below the freezing point due to the presence of salt or the chemical perchlorate. Orosei’s team described their findings in a paper that was published in Science in August 2018. He won’t be proven wrong, or right, for a long time. “Unless Elon Musk can get to Mars before NASA, any serious exploration of the Martian surface and what’s beneath is at least 20 years away,” he says. For now, Orosei has his sights on Jupiter’s moon Europa, which is suspected of harboring an ocean beneath its crust and will be within range of European and U.S. radar probes within the next few years.