Right here in our Galaxy - actually in our Sol-system, it's that close. And more alive than earth.
One of the moons of Jupiter, it's called Io and is alive with volcanic activity surpassing any found in our sol-system.
Io is covered in mountains, and an atmosphere composed of sulfur and sulfur dioxide frost - unlike most of our system's satellites. Io is basically one giant constant volcano. Above are the moons of Jupiter: Io, Europa, Ganymede and Callisto. The most promising for life is Europa which resembles our arctic and contains a subsurface ocean. Left is a direct downward look into an active volcano.
Volcanism is responsible for the incredible features of Io's surface. Gigantic lava flows and volcanic plumes paint the surface, green, red, blue, yellow, black, orange and white - all a result of the sulfurous compounds in the atmosphere.
There are no craters on Io because the volcanic activity erases them not long after they form. Very powerful volcanoes. Io is the same size and density of earth's Moon, so why is it so active? Seems to be the tremendous pull of Europa and Jupiter which continuously heat and melt the unique surface of Io.
Remember the Magnetosphere with protects us from the sun? Jupiter has an immense one, but little Io is barely protected. Io is pockmarked with activity, all manner of bombarding space objects, and generally thought to be, up to now, fairly sedate and quiet.
How wrong we were!
Io is more active, more alive geographically, than earth and in fact it is in this area of space we've been looking - from early days of Voyager to New Horizons, we've learned this forlorn body in space is more active than a 2-year old toddler. Again - what could this mean for the future of Jovian space?
Thank you Senior Galileo Galilei for your discovery.