If you want to book a vacation to hit the surf on Saturn’s wettest moon, Titan, you are alive at just the right time to look up your travel agent. Titan, which is known to be the only other planetoid in our solar system to have liquid on its surface, has just been shown to be the only other body nearby to have waves. Because these waves are in liquid methane rather than water, however, and exist at temperatures around -290 degrees Fahrenheit, it would have to be a specialized surfing trip involving a very protective wetsuit.
Scientists have been studying Titan for decades, with astronomers like Neil DeGrasse Tyson, Stanley Dermott and Carl Sagan and chemists like Bishun Khare positing first the possibility of life in the atmosphere of Titan, and later the possibility of actual liquid bodies on the surface. The liquid prediction was bolstered by the Hubble telescope in the 1990s and then proven true when the Cassini spacecraft reached Titan in 2004. Cassini has sent back pictures from under the thick blanket of methane and hydrocarbon gases that make up Titan’s atmosphere, and has even dropped a lander called the Huygens Probe, which was able to directly measure conditions on the surface.
These measurements made waves (pun intended) in the early 2000s as proof of stable liquids on Titan became public knowledge. Considering the temperatures on the frozen moon, it is somewhat of a backward world to human eyes in that most of the “rocks” and similar land features on Titan are made of ice, while its lakes, mostly clustered around the moon’s north pole, are made up of gases like methane which are liquid at those freezing temperatures.
Back in the 1980s, Sagan and Khare were able to prove that the materials existed in Titan’s atmosphere to produce the kinds of amino acids that on this planet are associated with the beginnings of life. Speculation has run rife since then about what kind of life might evolve in such an environment, composed as much of natural gas as it is of ice: speculation about whether life could exist at such temperatures even if a liquid element is present, and about what it would breathe and what it would consume. Scientists have posited that life-forms which could eat acetylene, such as is used on Earth in welding torches, could possibly breathe hydrogen.
The most recent news from Titan, however, is a matter of timing. In a recent pass Cassini has sent back data suggesting that light is reflecting off of Punga Mare, a large Titan lake, in a manner that suggests small waves of a few centimeters in height. Not surf-worthy, yet, perhaps, but they are harbingers of things to come.
Produced by new winds calculated to exist at 0.75 miles per second, these ripples have shown up on the placid lakes at the beginning of a Titan climate cycle. At two centimeters in height, the surf that is “up” on the Saturn moon is not exactly titanic as yet. However, it does appear that these tiny waves are only the beginning.
Titan experiences a round of seasons which lasts 30 Earth years. In this cycle, scientists posit, the liquid hydrocarbons on the surface of the moon are “pumped” from the south pole to the north and back again. The Huygens probe previously showed evidence of evaporation around Titan’s lakes similar to mineral deposits from evaporated water on Earth, such as salt flats, corroborating this theory.
Because of this long cycle, however, the evolution of storm conditions on the moon along with the evidence of wave activity on Titan’s lakes has only just begun, and would have been missed if Earthly probes had come visiting at another time in the cycle. Human technology necessary to discover these phenomena came about just at the right moment.
It appears from Cassini’s data that Titan has begun a sort of rainy season, in which methane rain moving hydrocarbons up from the south will fall into the lakes when it does not evaporate in sunlight, bringing about a shifting of the liquids around the moon. Winds which have begun on the surface and which might be responsible for the newly found ripples in the methane lakes are expected to pick up as the season progresses. Scientists posit waves of up to a meter as the season progresses.
Maybe not high enough a surf to be a challenge, but the waves now growing on Saturn’s moon, Titan, are a new frontier for science, and represent an uptick in human understanding of an entirely alien climate cycle and possible ecosystem. Certainly the other conditions on the planet would add enough of a challenge to make up for the small size of the oily otherworldly surf. With the great good luck of having produced the technology to witness this part of Titan’s cycle at the right time, there is little limit to what human science may learn from the moon.
By Kat Turner