To the eye, Saturn's giant moon Titan is rather boring -- an uninterrupted blanket of orange topped by a thin blue haze, as seen in this view from the Cassini spacecraft. Yet that blanket of orange helps make Titan one of the most intriguing objects in the solar system. The orange is a layer of smog produced by hydrocarbons, much like the smog on Earth. It conceals a surface that is molded by the motions of hydrocarbon rivers, dotted by hydrocarbon lakes, and partially covered by hydrocarbon dunes. The combination of chemistry and energy sources provide the key ingredients for life on Titan's frigid surface. [NASA/JPL/SSI]
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The planet Saturn is quickly pulling into view in the morning sky. It’s low in the east-southeast at first light, and looks like a fairly bright star. Right now, it’s to the lower left of Venus, the “morning star.” The two will slide past each other in a few days.
A telescope will show you Saturn’s largest moon, Titan. In fact, if you look at Titan with even a modest backyard telescope, you’ll know almost as much about the little world as professional astronomers did until well into the last century. It held onto its secrets because it’s so far away.
Dutch astronomer Christaan Huygens discovered Titan in 1655. In the 1880s, George Hill determined its mass by measuring its gravitational effects on the orbit of another of Saturn’s moons.
The first big breakthrough in understanding Titan came in 1944. Using the brand-new 82-inch telescope at McDonald Observatory, Gerard Kuiper detected the chemical “fingerprint” of methane, demonstrating that Titan has an atmosphere. It was the first moon in the solar system known to have any atmosphere, and it’s the only moon with a thick atmosphere.
Bigger telescopes allowed astronomers to see Titan more clearly, yet they revealed few details. That’s because a thick “haze” at the top of the atmosphere conceals not only the surface, but the rest of the atmosphere. More details about Titan awaited its first visitor from Earth — the Voyager 1 spacecraft. More about that tomorrow.
Script by Damond Benningfield, Copyright 2012
This program was made possible in part by a grant from the NASA Science Mission Directorate.