Titan’s True Colors

Titan’s True Colors

Titan in true color. Images taken with the narrow angle camera using red, green and blue spectral filters were combined to create this color view. The images were obtained at a Sun-Titan-spacecraft, or phase, angle of 67 degrees and from a distance of approximately 13.1 million kilometers (8.2 million miles) on June 10, 2004. Image scale is approximately 79 kilometers (49 miles) per pixel. Image Credit: JPL/Space Science Institute

Controllers have released this natural color image of Titan, Saturn’s largest moon.

The moon is surrounded by a thick atmosphere rich in organic molecules, which give it this featureless orange glow. Cassini will get a much better view soon, though, as it will make its first close flyby today. It will release the Huygens probe in early 2005 which will actually land on its surface and give scientists a better idea of what’s beneath those thick clouds.

Despite the views of Titan’s surface that Cassini is able to provide, the moon remains inscrutable to the human eye. In true color images that are taken in the visible wavelengths, Titan’s photochemical smog, rich in organic material, gives the moon a smooth featureless orange glow.

Titan, the largest moon of Saturn was discovered by Dutch astronomer Christian Huygens in 1655 and certainly deserves its name. With a diameter of no less than 5,150 km, it is larger than Mercury and twice as large as Pluto. It is unique in having a hazy atmosphere of nitrogen, methane and oily hydrocarbons. Titan, with a diameter about two-fifths that of Earth, ranks second largest of all the solar system’s moons after Jupiter’s Ganymede. As Saturn’s largest satellite, it is comprised of a 50-50 mix of ices and rock. The chemical composition of its environment resembles that of early Earth but it is far colder and lacks liquid water.

Titan’s atmospheric pressure near its surface is 60 percent greater than on Earth at sea level. Although it was explored in some detail by the NASA Voyager missions, many aspects of the atmosphere and surface still remain unknown. Titan was impenetrable to cameras aboard the Pioneer and Voyager spacecraft that flew by the Saturn system in the late 1970s and early 1980s. Thus, the existence of seasonal or diurnal phenomena, the presence of clouds, the surface composition and topography are still under debate. There has even been speculation that some kind of primitive life (now possibly extinct) may be found on Titan.

Titan’s changing face as dark and light patches rotate in circulation. Image Credit: JPL/Space Science Institute

One theory of Titan’s color is the abundance of an organic material called tholin. Tholin is a sticky, waxy, dark-red residue whose tiny particles cause the brownish haze.

Titan’s hydrocarbon haze is mainly this smoggy component containing molecules named from the Greek word, muddy. These aerosols can form the foundations of life’s building blocks and were first called "tholins" by Carl Sagan’s group.

The Cassini orbiter carries specially-designed spectral filters that can pierce Titan’s veil. Its piggybacked Huygens probe will descend through the atmosphere in early 2005, giving an up-close-and-personal look at this mysterious orange moon.

Huygens landing probe to Saturn’s moon, Titan.
Image Credit: ESA

There are 12 instruments onboard the Cassini Spacecraft orbiter, and 6 instruments onboard the Huygens Probe. The Huygens probe is geared primarily towards sampling the atmosphere. But the probe has no legs, so when it sets down on Titan’s surface its orientation will be random. And its landing may not be by a site bearing organics.





Related Web Pages

Chronology of a Scientific Safari
Long, Strange Trips
Titan’s Icy Bedrock
Saturn– JPL Cassini Main Page
Alien Landers: Extreme Explorers Hall of Fame
Titan: Biological Birthplace?
Solar System Bodies: Titan (NASA JPL)
The Probe Mission (NASA JPL)
Why Titan? (ESA)