NASA's Hubble Space Telescope released new images Monday, which will be published in The Astrophysicial Journal later this week, that show what appears to be plumes of water vapor erupting out of the icy surface of Jupiter's moon Europa. The discovery is especially intriguing as it means that the ocean below Europa's surface could be probed without having to drill through miles of ice. NPR reports: Europa is one of the most intriguing places in the solar system because it's thought to have a vast subterranean ocean with twice as much water as Earth's oceans. This saltwater ocean is a tempting target for astrobiologists who want to find places beyond Earth that could support life. The trouble with exploring this ocean is that the water is hidden beneath an icy crust that's miles thick. But if plumes are indeed erupting from Europa, a spacecraft could potentially fly through them and analyze their chemistry -- much like NASA's Cassini probe did recently when it sped close to Enceladus, a moon of Saturn that has small geysers. Scientists used Hubble to watch Europa's silhouette as the moon moved across Jupiter's bright background. They looked, in ultraviolet light, for signs of plumes coming from the moon's surface. They did this 10 separate times over a period of 15 months, and saw what could be plumes on three occasions. NASA says the plumes are estimated to rise up about 125 miles, and presumably material then rains back down onto Europa's surface. Using Hubble in a different way, scientists previously saw hints that salty water occasionally travels up to the moon's surface. In 2012, the telescope detected evidence of water vapor above Europa's south polar region, suggesting the existence of plumes that shoot out into space. The agency's Juno spacecraft is currently in orbit around Jupiter, but it isn't slated to take any observations of Europa.