Hunch Leads Astronomer to New Neptune Moon Planet's 14th moon is just 12 miles across By Rob Quinn, Newser Staff Posted Jul 16, 2013 2:18 AM CDT 3 comments Comments This diagram provided by NASA shows the orbits of several moons located close to the planet Neptune. (AP Photo/NASA) (Newser) – An astronomer poring over old images from the Hubble Space Telescope has discovered a previously unknown 14th moon of Neptune. SETI Institute researcher Mark Showalter—who has five other moon discoveries to his name—followed a hunch while studying ring segments around the planet and tracked a white dot to find the tiny moon, the Atlantic reports. The moon—called S/2004 N1 for now—is believed to be just 12 miles across and is so small and dim that it is 100 million times fainter than the faintest star that can be seen with the naked eye, NASA says. The images used to make the latest find in our solar system were taken by Hubble between 2004 to 2009 and had long been in the public domain, so "anyone could have discovered this," Showalter says modestly.