A Planetary Odd Couple
This artist's conception shows Kepler-36c as it might look from the surface of neighboring Kepler-36b.
The two planets are far too close to the sun to be in the habitable zone, but they are bizarrely close to each other; on their closest approach, they come within about 1.2 million miles (1.9 million kilometers) of each other.
Kepler-36b is a rocky world, measuring 1.5times the radius, and 4.5 times the mass, of Earth. Kepler-36c is a gaseous giant, measuring 3.7 times the radius and eight times the mass of Earth.