The Thick Ice of Europa: A Barrier or a Gateway to Alien Life?

Jupiter’s icy moon may be the next place where humans find life, but first, they need to understand its structure.
Planetary physics can often feel like being in a snowball fight. When given an already-formed snowball, most people can leverage their experience and the texture of the snowball to determine its composition: whether it’s made of soft, packable snow or hard, icy snow.

Using nearly the same principles, planetary scientists have been able to study the structure of Europa, Jupiter’s icy moon.

Europa is a rocky moon, home to saltwater oceans twice the volume of Earth’s, encased in a shell of ice. Scientists have long thought that Europa may be one of the best places in our solar system to look for nonterrestrial life. The likelihood and nature of that life, though, heavily depend on the thickness of its icy shell, something astronomers have not yet been able to ascertain.