When it comes to candidates for alien life in our solar neighborhood, Europa is the apple of every scientist's eye.

The moon — one of 79 whirling around Jupiter — has already offered a few tantalizing hints. Earlier this year, a detailed analysis of the satellite revealed that it’s covered in salt, suggesting a vast, very Earth-like ocean beneath its icy enamel.

And now, NASA is hailing an even bigger breakthrough. According to a research paper published in the journal Nature Astronomy, plumes of water vapor are bursting from the moon’s surface.

They’re scarcely detectable from Earth — just one of 17 observations by the W. M. Keck Observatory in Hawaii was able to pick up on a faint plume released from Europa’s surface.

But it’s enough to dramatically heat up the hunt for life beyond our planet.

"While scientists have not yet detected liquid water directly, we've found the next best thing: water in vapor form," lead researcher and NASA planetary scientist Lucas Paganini noted in a NASA release.

And although spectrographs taken by the W. M. Keck Observatory could just barely make out the plumes, scientists say the moon is releasing a massive amount of water vapor — enough to fill an Olympic-size swimming pool within minutes.

That adds credence to the suspicion that the ocean lurking beneath Europa’s frozen shell is incredibly vast. NASA suspects that shell is between 10 and 15 miles thick. And below, lies a saltwater ocean that plumbs a dizzying depth of anywhere from 40 to 100 miles. Compare that to the 2.3-mile average depth of Earth’s oceans.

And suddenly, we’re swimming in all kinds of possibilities.

“We performed diligent safety checks to remove possible contaminants in ground-based observations," Planetary scientist Avi Mandell notes in the NASa statement. “But, eventually, we'll have to get closer to Europa to see what's really going on.”

NASA is already planning to dip a toe in those waters.

The space agency’s Europa Clipper mission could put a spacecraft, brimming with cameras and spectrometers, in Jupiter’s orbit as early as 2023. From there, it will perform 45 flybys of the icy orb, performing the most detailed analysis of the moon’s surface yet.

And perhaps even do a little fishing.

NASA just found plumes of water vapor bursting from Jupiter's moon
Water vapor escaping Europa hints at a vast saltwater ocean beneath its surface.