Furthermore, to keep our comparison with our very own old, long-in-the-tooth planet, this youngster is 10 times the size of the Earth. It has a third of the mass of Jupiter. We could say that we have ...

For the better part of a century, we believed there were nine planets in our ... being so similar in size, some consider Pluto and Charon to actually form a double-planet system.

Finding new planets lurking ... as how long it takes the planet to complete an orbit and how much light it blocks as it passes in front of the star offer clues to its size and orbit.