The results appear this month in the planetary-science journal Icarus. At 3,200 miles in diameter, Titan is larger than the planet Mercury and is the only body in the solar system with a nitrogen-rich atmosphere like the Earth's. Observing Titan is extremely difficult. High in Titan's atmosphere, ultraviolet light changes methane gases into a thick smog-like organic haze that hides Titan's surface. When the Voyager spacecraft passed by in 1980, it saw only the orange-brown top of Titan's smoggy skies.
Infrared light can penetrate the smog to see Titan's surface.
Unfortunately, Titan is so far away that conventional telescopes see only a fuzzy blob because the image is blurred by Earth's atmosphere. Even the Hubble Space Telescope lacks sufficient resolution, especially in infrared light, to see much detail, though both Hubble and ground-based studies have shown that Titan has a complex surface. With the tremendous power of the Keck Telescope we are able to map surface features 150 miles in size on a moon that is more than 800 million miles from Earth. I telescope, the world's largest, on Mauna Kea, Hawaii. UCLA Professor Andrea Ghez was a pioneer in applying this technique to infra-red astronomy.