Jupiter’s big moon Europa is one of the most likely bodies in the solar system to host life. The moon has a global ocean that holds more water than all of Earth’s oceans combined. The ocean might have sources of energy and chemical compounds that are needed to support microscopic life.

But getting to that ocean won’t be easy. It’s covered by a crust of ice. And a recent study says the ice is pretty thick.

The Juno spacecraft scanned part of Europa with an instrument that can probe conditions below the surface. It found that the average thickness of the ice is about 18 miles. That’s thicker than suggested by some earlier studies. Juno found many cracks in the ice. But they don’t penetrate anywhere close to the water. So there doesn’t appear to be a good way to get through the ice to study the ocean.

That also could be a problem for any organisms in the ocean. Jupiter’s radiation zaps material on the surface, transforming it into possible nutrients.

Without any holes or thin spots in the ice, there’s no direct way to flush the nutrients into the water. But another study found that large concentrations of nutrients could make blocks of ice denser than the surrounding ice. Over time, the heavier blocks could sink all the way through the ice – perhaps helping to sustain any life in Europa’s hidden ocean.

Jupiter is high in the west at nightfall, and looks like a brilliant star. The twins of Gemini stand above it.

Script by Damond Benningfield