New research suggests that lakes of liquid water could be buried in the icy crust of Europa, a moon of Jupiter. The processes that create the lakes could also provide nutrients crucial for life on Europa, the scientists say. 
 
 A file image from the Galileo spacecraft shows the Conemara region of Jupiter's frozen moon Europa. Scientists say the surface features suggest that a lake of liquid water once existed beneath the ice. 
 
 Mysterious depressions and domes on Jupiter's ice-encrusted moon Europa may signal the presence of subsurface lakes, at least one of which holds enough water to fill the American Great Lakes. 
 
 The finding, if confirmed, could be a boost for those who speculate that simple forms of life could exist on the moon. 
 
 For several decades, scientists have known that an ocean of liquid water exists beneath Europa's crust of ice. But some research suggests that Europa's ice shell could be miles thick. The subsurface lakes described by NASA scientists Wednesday, however, appear to exist within that icy mantle, meaning they would be at a far shallower depth than the underlying ocean. 
 
 Moreover, the lakes could be part of a planetary dumb-waiter system that transfers potential nutrients from the surface to the subsurface ocean, the team suggests. That transfer of nutrients could be crucial to any potential life on Europa. 
 
 With liquid water, Europa already has one necessary ingredient for life. That has made it "a compelling object for study for decades," says Tori Hoehler, an astrobiologist at NASA's Ames Research Center in Moffett Field, Calif., who was not part of the research team. 
 
 But another requirement for life, he adds, is a source of energy, a.k.a. food. The moon's upper crust is rich in compounds that could be a food source, but the potential nutrients would need a system to deliver them to the ocean deep below. 
 
 The mechanism that forms the subsurface lakes – involving rising plumes of heat – could provide that service, the team suggests. 
 
 If the team is right, "you've moved from a system that checks [off] one of the requirements for life to a system that checks two requirements for life," Dr. Hoehler says. 
 
 The results, set for publication in Thursday's issue of the journal Nature, grew out of an attempt to explain two different areas within Europa's "chaos terrain" – a landscape of jumbled surface features visible in images from the Voyager and Galileo spacecraft. 
 
 The two areas that have puzzled scientists cover significant large patches of the moon's surface and host icebergs with ground-up ices filling the channels in between – much as jumbled ice chunks fill gaps between icebergs as they calve from ice shelves in polar regions on Earth. 
 
 One of the two areas appeared as a depression in the surface. The other appeared as a dome. 
 
 "Why are these two features so similar but so different?" says Britney Schmidt, a planetary scientist at the University of Texas at Austin who led the research team. 
 
 In trying to solve the puzzle, the team was struck by parallels on Earth. Similar features are apparent in ice that forms above under-ice volcanoes, as well as at ice shelves where warm sea water is thought to be thinning the ice from underneath. 
 
 The team suggests that plumes of warmer water, heated by Europa's core, migrate up through the thick icy crust until they reach a "sweet spot" where a combination of pressure, temperature, and the composition of the ices allows a subsurface lake to form. Since liquid water takes up less volume than water ice, the icy lid on top of the lake begins to crack and collapse in a kind of frigid sink hole. The surface ice breaks into chunks in the process. As it does, some of it overturns, mixing the potential nutrients into the water below. 
 
 That explains the depressions. But what about the domes? 
 
 Over time, the lake refreezes and expands. This pushes remaining large ice blocks upward. The brine surrounding the blocks also refreezes, expanding as it does, adding to the dome. 
 
 One of the features, Thera Macula, is a depression, suggesting that a Great Lakes-scale body of water some two miles below currently is sculpting the surface, the team says. A dome feature, known as Conamara Chaos, represents the end of another lake's thaw-freeze process. 
 
 Over time, researchers have debated whether the icy shell covering Europa is thin or thick – thick roughly defined as more than six miles top to bottom. But neither camp can adequately explain how the chaos terrain forms, the team posits. 
 
 The team's new explanation "is a really interesting half-way point that is much more realistic," says Geoffrey Collins, a planetary scientist at Wheaton College in Norton, Mass. "It's not just 'only liquid down here and only ice up there.' There are perched lakes or slushy areas in the ice shell that may be having a huge effect on the surface geology," he says. 
 
 The thin-thick argument is of interest to astrobiologists, says Dr. Collins. If the crust is thick – say, 18 miles or so – that would leave little hope of ever being able to sample the ocean and check for signs of life. If it's thin, hope would spring eternal for sending a robotic mission to study what's beneath. 
 
 The new explanation leaves open the possibility for exploring potentially habitable environments even if the icy shell turns out to be a thick one. 
 
 Collins, however, is less convinced that the process can bring nutrients in the upper crust down to any hidden ocean. In the scenario the team lays out, the heat plumes that form the lakes – and the lakes themselves – don't come into contact with an ocean at any depth below the surface. 
 
 But Curt Niebur, NASA's program scientist for the outer planets, explains that it's possible the overturning ice can transfer any potential nutrients to the water or slush below. That leaves the enriched material free to migrate back down through cracks in the ice. 
 
 These ideas require missions to Europa to test them, researchers acknowledge. 
 
 Even so, "I'm really excited" about the team's proposed solution to the chaos terrain conundrum, Collins says. Thick shell or thin, if the presence of the lakes can be verified, they could be "interesting, accessible bodies of liquid water." ||||| Jupiter’s smallest Galilean moon, Europa, not only has a massive global ocean, it has huge lakes beneath its icy crust, according to new research. 
 
 NASA has been very confident for about a decade that there is a huge ocean on Europa, according to NASA program scientist Curt Niebur. But the ocean is capped by an ice crust and no one was sure about its thickness. Europa is relatively large among the dozens of moons of Jupiter. 
 
 Some scientists thought it was a mile or two thick, but most scientists thought it was several miles thick. A thick crust would be bad news for life because it would mean the ocean could never splash up on Europa’s shores to interact with possible sources of food needed to sustain life. 
 
 New research announced Wednesday indicates the crust is thick, but it also shows that there are lakes above the oceans and that they are churning. This is key, because it means possible life forms in Europa’s oceans could make it the surface via the lakes to find food. 
 
 "One opinion in the scientific community has been, 'If the ice shell is thick, that's bad for biology — that it might mean the surface isn't communicating with the underlying ocean,' " according to Britney Schmidt, a postdoctoral fellow at The University of Texas at Austin's Institute for Geophysics and the lead author of a new study published in the journal Nature. 
 
 "Now we see evidence that even though the ice shell is thick, it can mix vigorously. That could make Europa and its ocean more habitable," she said in a statement. 
 
 This is fantastic news for scientists hoping find signs of life on Europa, said Niebur. 
 
 The lakes are estimated to be 2 to 3 miles below the crust, while the oceans are estimated to be 30 miles down, Niebur said. “It’s a missing link to understanding to whether it (Europa) could support life.” 
 
 Scientists are basing their findings, in part, on what they learned from images taken by the old Galileo spacecraft, which was launched in 1989 to gather data and images from Jupiter and its moons. (It crashed into Jupiter in 2003). Those pictures show round bumps called chaos terrains. Based on the way ice moves around on Earth, the researchers developed a model to explain the bumps. 
 
 The only way to confirm the model would be to fly a spacecraft to Europa to investigate. A mission is on the drawing board, but NASA hasn’t approved anything yet, according to Niebur.
– The chances of life existing on Jupiter's ice-covered moon Europa—and of Earthlings being able to find it—are looking a lot stronger, NASA scientists say. A vast ocean is believed to lie beneath as much as 20 miles of ice on Europa, but new research suggests that huge lakes exist a lot closer to the surface. A suspected interchange of water between the lakes and the ocean means that nutrients could be transferred from near the surface to life far below, the BBC reports. The research team examined bumps known as "chaos terrain" on Europa's surface and developed models based on the way ice moves around on Earth. If the researchers are right, "you've moved from a system that checks one of the requirements for life to a system that checks two requirements for life," an astrobiologist tells the Christian Science Monitor. The only way to confirm the findings would be to send a spacecraft to Europa to investigate. A mission is on the drawing board but NASA hasn't approved anything yet, CNN notes.