125: Oceans, oceans everywhere with Dr. Keane
Dr. James Tuttle Keane discusses why Pluto probably has a huge underground ocean. To make this discovery, he used images of Pluto taken by the New Horizons spacecraft, computer simulations, and good old-fashioned pen and paper.
Don't miss Dr. Keane's planetary illustrations on his twitter feed.
Image: Sputnik Planitia as seen by New Horizons.