Montana Skies: Jupiter's mysterious moon Europa

In this week's Montana Skies Dr. Kelly Cline says the absence of our moon means Jupiter is highlighted. Tonight Dr. Cline tells us Jupiter has a mysterious moon of its own.

We have what astronomers call a "New Moon" out tonight, which there's no moon to be seen at all.  In a few days, we'll start to see a thin crescent moon in the evening sky, just at sunset. But for now, gargantuan Jupiter continues to dominate the night time action, and what an amazing planet it is.  It's the brightest thing anywhere in the sky, high up to the South. Jupiter has over sixty moons. And tonight, Jupiter's most mysterious moon will be passing right in front of it, making a tiny little eclipse, only visible with a telescope. This moon is called Europa.

Wow! Look at this crazy moon.  The surface of Europa is covered in ice, real water ice, the same stuff we drive on around here. And look at all these weird brown cracks covering the surface.  That's because gravity from Jupiter and the other moons is constantly squeezing, and stretching, and squashing Europa, breaking up that ice.  Then this dark brown stuff comes oozing up from under the ice, leaking out onto the surface. What's that stuff?  It's water, dirty salt water. If we zoom in for a closer look we see this.

Holy cow! We call this "Chaos Terrain" and you know what those are? Those are ice bergs, floating around in a freezing, slushy sea.  Our calculations tell us that if we could peal back the layers of Europa and look inside, we'd see something like this.

That's an ocean of liquid salt water a hundred miles deep underneath a crust of ice that's an average of 15 miles thick. Is anything swimming around in that ocean?  NASA's working on a space probe to Europa to find out. So think about that when you take a look at mighty Jupiter, high in the South, up in our Beautiful Montana Skies.