Weather on Saturn’s largest moon, Titan, cleared this past summer, allowing NASA’s Cassini spacecraft to beam back revealing views of the giant lakes and Earth-like salt-flats that adorn the frozen mini-world.
Northern spring is kicking into high gear on the ringed giant’s largest moon, bringing with it clear breaks from the cloudy winter weather. That is finally allowing the orbiter’s infrared instruments to get a clear glimpse of the seas of liquid methane and ethane on the moon. (See “Spring Rains Darken Saturn’s Moon Titan.”)
Other than Earth, Titan is the only other world in the solar system that appears to have stable bodies of liquid on its surface, except on this distant moon because surface temperatures are a nippy – 290 degrees Fahrenheit, the liquids here are not water but hydrocarbon.
For some yet-unknown reason, most of Titan’s lakes appear congregated around the smoggy moon’s north pole. Now that the smog is dissipating in the northern hemisphere, Cassini’s sensitive infrared mapping spectrometer and cameras are getting their clearest views yet of the moon’s mysterious land of lakes.
“Titan’s northern lakes region is one of the most Earth-like and intriguing in the solar system,” said Linda Spilker, Cassini project scientist in a statement.
“We know lakes here change with the seasons, and Cassini’s long mission at Saturn gives us the opportunity to watch the seasons change at Titan, too. Now that the sun is shining in the north and we have these wonderful views, we can begin to compare the different data sets and tease out what Titan’s lakes are doing near the north pole,” said Linda Spilker, Cassini scientist.
The new images reveal never-before-seen bright areas that appear unique to the northern hemisphere. Scientists hope these views will offer clues as to why the lakes are concentrated in the region.(See “Methane Rain Formed New Lake on Saturn Moon.”)
The largest of the dark shapes, at the upper right of the black and white image, is Kraken Mare, Titan’s largest sea—equal in area to the Caspian Sea and Lake Superior, combined. To its left lies Ligeia Mare, about 300 miles (roughly 500 kilometers across), the second largest sea. Titan’s north pole, marked with a cross on this image, is just above Punga Mare, some 240 miles (380 kilometers) across.
Also visible in the top color image is the orange-colored terrain that surrounds the great lakes. Researchers believe these could be salt flats made of organic material. The deposits may have formed as the lakes and seas began to evaporate with the approach of summer, bringing warming temperatures. (Related: “Saturn’s Largest Moon Has Ingredients for Life?”)
“Ever since the lakes and seas were discovered, we’ve been wondering why they’re concentrated at high northern latitudes,” said Elizabeth Turtle, a Cassini imaging team associate based at the Johns Hopkins Applied Physics Laboratory, Laurel, Md. “So, seeing that there’s something special about the surface in this region is a big clue to help narrow down the possible explanations.”
Launched in 1997, Cassini has been circling the Saturn system since 2004. Since an entire trip around the sun—one Saturnian year—lasts 30 Earth years, Cassini has been able to observe nearly a third of the ringed planet’s year. In that time, Saturn and its moons have seen the seasons change from northern winter to northern summer.