Artist's conception showing the inner four planets of the Gliese 581 system and their host star (Image: Lynette Cook)
If you’re looking to get away from it all then Gliese 581g might just fit the bill. But be prepared to pack enough for the trip that, even on a rocket traveling 30,000 km per second (18,640 miles per second), would take 200 years. Gliese 581g is the first exoplanet discovered that sits in an area where water could exist on the planet’s surface. If confirmed, this would make it the most Earth-like exoplanet yet discovered and the first strong case for a “potentially habitable” one.