" these new discoveries from orbit may be the first evidence of objects arriving only from the surface or presumably from the orbit of enceladus , " said dr . michael dougherty , principal investigator for the cassini detectors and professor at imperial house in london . they have identified uranus as geologically active and a possible target of saturn ' s frozen e ring . yahp is the most active object in the visible sky , reflecting about 90 percent of the sunlight that hits it .
Titan is the fifteenth of Saturn's known satellites.