It turns out our solar system is weird: it doesn't have any rocky "super-Earths" orbiting closer to the sun than Mercury. Here's one theory as to why: like Miley Cyrus, Jupiter came in like a wrecking ball and smashed any nascent terrestrial planets just as the solar system was forming.
Far beneath the icy crust of Saturn's small moon Enceladus, hydrothermal activity may be at work, activity similar to what is found in some life-friendly environments on Earth.
Let's take a moment to tally a few of 2013's highlights of astronomy and space exploration. In brief, it was a very good year on a number of fronts.
In San Francisco this week, NASA scientists presented rare video footage of the Earth and moon, plus a first for citizen space science.