“We’d seen hints of interesting subsurface features for years, but we couldn’t reproduce the result from orbit to orbit,” says study co-author Andrea Cicchetti, who’s also on the MARSIS team. She says data resolution in the past was just too low. But the team found a new way to operate the instrument that avoids processing data on the aging spacecraft and instead sends observations to Earth, allowing a higher sampling rate.The discovery is especially intriguing because underground lakes like this are also found near Earth’s poles, particularly in Greenland and Antarctica. And in recent years, scientists actually drilled deep beneath the Antarctic ice into one of these, the subglacial Lake Whillans , which had been cut off from the surface for millions of years. They found bacteria still living there in complete isolation.Scientists have also traveled deep underground into mines and found microorganisms related to ancient species that once lived in watery environments much closer to the surface. Such migrations raise the possibility of the same thing happening on Mars — as the water retreated, life moved deeper underground.However, while the find is tantalizing for astrobiologists eager to find alien life, it’s also a bit of a tease. It will be decades before astronauts can visit the surface of Mars, and likely much longer before we can drill a mile beneath the dusty surface. So we may not see any Martian fishing expeditions in our lifetime.This article originally appeared on Discovermagazine.com