Titan's morning weather forecast: Widespread drizzle

This false-colored image of Titan shows surface details and atmosphere. "Xanadu" is the bright region at the center right. Image credit: NASA/JPL/Space Science Institute

Mornings on Saturn’s moon Titan are often cloudy and drizzly over a wide area, according to a new astronomy/weather report by astronomers using giant telescopes on Earth.

Titan is one of 60 known moons of Saturn, our sixth planet. It is larger than our moon and is the only heavenly body other than Earth that has huge, stable areas of surface liquids.

In 2004, the Huygens probe, named for the Dutch astronomer who found the moon in 1655, landed on Titan. It landed on a damp surface that was wet with methane mist after descending through clouds of methane. The probe only provided information about a very small area on the large moon.

Máté Ádámkovics and colleagues recently used advanced instruments at two large telescopes that allowed them a better view than ever before possible. They detected widespread precipitation, or drizzle, of methane from horizontal clouds around the equator of Xanadu, one of Titan’s brightest continents.

This research supports the findings of the Huygens probe and expands it over a larger area. Researchers even predicted weather conditions based on their knowledge of weather on Earth. They write that on Titan, the prevailing eastern winds transport a moist mass of air up over mountains, and that night time cooling brings morning mist of methane to Xanadu.

The majority of Saturn’s atmosphere is hydrogen, with about 1 percent of methane. These astronomers answer another question about Titan. That small amount of methane needs to be replenished. Adamkovics and coauthors suggest that the widespread methane drizzle is a closed cycle and continually replenishes the methane cycle much like Earth’s hydrological cycle.

This study appears in the 11 October issue of Science Express.

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