A new rocky exoplanet has been discovered that is the closest one to Earth at 21 light-years away. The alien planet, with the catchy name of HD 219134b, is said to be 4.5 times more massive than our world, qualifying for the "super Earth" category. It orbits close to its star, traveling around it in just three days, so it's thought to be too hot to harbor life as we conceive of it. More at Space.com.