Planet of the Week: Europa

Europa is one of 63 known moons of Jupiter, and perhaps is the most fascinating of them, simply because there is evidence of water. In fact, Europa once had a sea of liquid water below this crust, and it's possible that this is still the case. This possibility was first discovered by the Galileo Spacecraft (Galileo actually discovered Europa), which has taken images that offer insight into the icy crust and the ridges that are evident upon it. These ridges could be caused by cryovolcanism (the eruption of ice and water), and essentially mean that there are contaminants in Europa's icy crust. Europa is a relatively young moon, because it doesn't have any evidence of a large amount of interstellar collisions upon its surface.

The moon of Europa

Cryovolcanic ridges on Europa's icy crust

The Galileo Spacecraft

This clip from "How the Universe Works" truly puts our size into perspective. When you think about the fact that there are over a hundred billion stars in our galaxy alone, you can realize how infinitely small we are. VY Canis Majoris is a billion times larger than our own sun. This means that it is 1000000000000000 times larger than Earth. A billion of something is more than the grains of sand we have on our own planet (to put such a number in perspective). This video is the epitome of our incredible insignificance, and is truly a humbling experience.