NASA, through their Cassini spacecraft, has taken the best photos yet of Titan’s numerous lakes. The latest images even reveal what might be “salt flats” of sorts. Titan (Saturn’s largest moon) is the only other place, besides Earth, that has so far been found to have stable bodies of liquid on it; though, the liquid is not water. Instead, Titan’s hydrocarbon lakes contain liquid ethane and methane.
The images that Cassini captured are infrared ones, and are visually exceptional. The reason Cassini was able to capture such phenomenal photos is that it’s spring time on Titan, a rain-free period on the planet-sized moon. Also, Titan was on an orbital path that afforded Cassini’s visual instruments improved geometry set of parameters to obtain high-quality images.
Right now, in the hydrologic cycle of Titan’s weather, hydrocarbons are being put back into the atmosphere of the moon. The recent images that Cassini have been taking provide added insights into this stage of Titan’s hydrologic cycle.
According to the head of Cassini’s imaging team, Carolyn Porco, they have also discovered a “bright material not seen elsewhere on Titan,” surrounding some of the northern lakes of Titan. She speculates that the bright material might be evidence that the lakes and seas on Titan are beginning to evaporate. If so, the bright material might be deposits of organic material, Titan’s equivalent of Earth’s slat flats, though they wouldn’t actually be composed of salts at all.
Scientists theorize that the deposits may be organic compounds that previously were a component of the methane-heavy haze which surrounds Titan. The bright materials could have dissolved into the methane lakes, and then, after some of the methane evaporated, it could be they were left behind.
What are the “salt deposits” of the lakes of Titan composed of?
No one at this stage know for sure what the “salt deposits” which seem to be a product of the evaporation of Titan’s lakes and seas are composed of. As Jason Barnes, one of the scientists who are involved with interpreting the images that Cassini takes with its VIMS imaging instrument recently said to NBC News via an email, since the bright deposits are likely “non-polar” materials like ethane and methane, they are not actually “salts.”
The images and other data which Cassini is sending back to scientists are not only giving them new insights into Titan’s weather patterns, but also it’s providing the scientists information about the chemicals in Titan’s environment. The atmosphere and chemical environment of Titan might be similar to the type of prebiotic chemistry that Earth once had, prior to the appearance of life on our planet. The thick haze that envelopes Titan has made it difficult, before now, to learn much about Titan’s chemical signatures and processes..
For whatever reason, or sets of reasons, most of Titan’s lakes are located near its north pole. By comparing the data that Cassini is gathering from the different seasons on the moon, according to another Cassini project scientist, Linda Spilker, the scientist might be able to “tease out what Titan’s lakes are doing near the north pole.”
Before turning its attention to Titan, Cassini had been monitoring Saturn since 2004. It had been sending back data about a third of one of Saturn’s years, which last the equivalent of 30 Earth years.
What are the sizes of Titan’s lakes compared to Earth’s?
Some of Titan’s lakes and seas are relatively large. Titan’s largest sea is Kraken Mare. It is as big as Lake Superior and the Caspian Sea combined. Ligeia Mare is Titan’s second largest sea, and is about 500 km wide. Another sea in the northern hemisphere, Punga Mare, is about 380 km wide.
Cassini’s images of Saturn have been the subject of much speculation by scientists, also. An example is a “mysterious six-sided weather pattern known as the hexagon” which is “visible around Saturn’s north pole,” according to a statement by NASA.
It was winter in Saturn’s northern hemisphere when Cassini began investigating the planet in 2004. The are had, for some reason as yet to be determined, a bluish hue to it. In the southern hemisphere, on the other hand, where it was summer, gold-colored tones dominated.
Titan has been the subject of tons of both scientific theories and science fiction short stories and novels. That’s probably because it has seemed to be, other than Mars, the closest equivalent moon or planet to Earth.
The presence of so much ethane and methane in Titan’s atmosphere suggests that there is probably no life on the moon, unless it’s the type that can survive in harsh environments like near thermal vents that are deep in oceans on Earth, or perhaps conditions like areas of geothermal activity, such as Yellowstone Park. Titan might not have life on it, but it’s still a fascinating moon that is, thanks to Cassini, yielding more of its secrets.
Written by: Douglas Cobb