Four moons circling Jupiter? What a sensation when Galileo discovered them in the early 17th century! They're still amazing. Find out which one is bigger than a planet, which seethes with volcanic activity and has mountains taller than Everest, and where there is an ocean that could harbor life.

Jupiter's Galilean Moons

I've made a Pinterest board of pictures related to this article.

You have a wonderful astronomy site. And I love how you've added the pinterest boards. My husband teaches technology at the high school and he's always looking for new ways to communicate online. Very cool!

Thank you for your kind comments, Alice. Other BellaOnline editors were using Pinterest, so I looked at it and thought it would be a wonderful way for people to see the pictures that my articles linked to - and some that I discover after putting up the article. I even find that I enjoy looking at them myself!