In this artist’s illustration, an extrasolar gas giant planet – known to earthly astronomers as Kepler-36c – looms in the sky of its close neighbor, a rocky volcanic world called Kepler-36b. Astronomers at the Harvard-Smithsonian Center for Astrophysics (CfA) published a study about these two worlds on June 21, 2012. They say these worlds constitute closest two-planet system yet found. When the two worlds are closet, say the astronomers, the co-orbiting gas giant planet Kepler-36c would span three times more sky than a full moon does from Earth.
The astronomers say these two planets in the Kepler-36 system have repeated close encounters, experiencing a conjunction every 97 days on average. At that time, they are separated by less than five Earth-Moon distances. If so, these close approaches would stir up tremendous gravitational tides that squeeze and stretch both planets. These forces could promote active volcanism on Kepler-36b.
Astronomer Josh Carter of CfA said:
These two worlds are having close encounters.
Co-author of the study – Eric Agol of the University of Washington – added:
They are the closest to each other of any planetary system we’ve found.
Deborah Byrd created the EarthSky radio series in 1991 and founded EarthSky.org in 1994. Today, she serves as Editor-in-Chief of this website. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named 3505 Byrd in her honor. A science communicator and educator since 1976, Byrd believes in science as a force for good in the world and a vital tool for the 21st century. "Being an EarthSky editor is like hosting a big global party for cool nature-lovers," she says.