For anyone mildly interested in exoplanets, you are familiar with the term ‘Goldilocks Zone’. This is the region of space around a star where conditions are ‘just right’ for liquid water to exist on the surface of a planet. Liquid water is necessary for our type of life to evolve. Everywhere on Earth where we find water – underneath ancient arctic ice, at the bottom of the oceans, and even in the clouds – we find thriving life. This gives us a way to predict the habitability of planets or moons we find. If we see evidence of liquid water, the planet or moon becomes more exciting, for it too may harbor life.
National Geographic has an amazing graphic depicting all the various world's and there place in (or out of) the Goldilock's zone. In the image, the circular dots stand for planets. The infograph lists the mass of the planet according to how many Earth-masses it is. You can also scroll over the planets to get their names, radius, and exact mass. Check out the full, interactive graphic here.