Really Close Alien Planets Experience ‘Planetrise’

Astronomers have discovered two alien planets circling the same star and there orbits are believed to be so close together that they each rise in the night sky of their sister planet. Standing on either planet would essentially look like an exotic full moon rising and falling in the sky.

Located 1,200 light-years from Earth the planets differ greatly in size and come within 1.2 million miles of one another, closer than any other pair of planets ever discovered.

The planet Kepler-36b is 4.5 times the size of our own planet and is known as a rocky “super-Earth.” Kepler-36b likely features 30 percent Iron, 15 percent water and atmospheric hydrogen with less than 1 percent helium. The other planet, called Kepler-36c is a gaseous Neptune-size world nearly eight times as massive as Earth. 36c is believed to have a substantial atmosphere filled with hydrogen and helium.

Every 97 days the planets meet in conjunction and become their most visible in each others sky.

When the two planets reach their closest distance they are five times the distance from Earth to the moon.

In an email to Space.com co-lead author Eric Agol notes:

“They are as different in density as Earth and Saturn (the highest and lowest density planets in our solar system), yet they are 30 times closer than any pair of planets in our solar system.”

The planets were detected by NASA’s Kepler Space Telescope.

Kepler-36c orbits once every 16 days at an average distance of 12 million miles while Kepler-36B orbits every 14 days and sits 11 million miles from its star.