NASA thinks this frigid world is our best hope of finding alien life - here's why

But once you know that moon hides a vast subsurface ocean - what astronomers think is the most likely place we'll find life beyond Earth - you might wonder why it's taken us so long to get there.

That moon is called Europa, and NASA got the green light last summer to plan a mission to explore it.

And now, with NASA's 2016 budget got an unexpected $1.3 billion raise, it looks like a mission to Europa is closer to being a certainty. About $175 million of the 2016 budget is earmarked for Europa, with $25 million of that going toward developing a lander to touch down on its surface.

It will be at least a few years before a spacecraft and lander launches - they'll have to hitch a ride on a colossal rocket NASA hasn't built yet. Still, the space community is psyched.

Here's what makes Europa such an important place to explore, according to a video from NASA: