Ocean waves spotted on Titan are the first ever seen on a world other than the Earth.
The remarkable sight was detected by the Cassini spacecraft orbiting Saturn. The waves were observed on Punga Mare, a sea on Titan, 235 miles wide.
Oceans on Saturn's largest moon are composed of methane, ethane and other hydrocarbons. With an average surface temperature of almost 300 degrees below zero Fahrenheit, these chemicals remain liquid on the surface of Titan.
The frozen, miniature world has a dense atmosphere, winds and rains hydrocarbons. The landscape is frozen, with iceforms continually shaped by the wind and precipitation. Titan experiences seasons, but they run on a 30-year-long cycle.
The strong winds, rain and low gravity led astronomers to believe waves should be common on Titan. However, for the first 90 passes of the giant satellite, all cameras aboard Cassini observed were still seas all over the surface.
Jason Barnes of the University of Idaho studied images taken by the spacecraft back in 2012. These photographs were taken of Titan's north pole, and showed light reflecting off Punga Mare. This light appeared to be reflecting off hydrocarbons, in the same way sunlight reflects off water here on Earth. He set to work to determine if waves were the cause of the reflection.
Barnes and his team became convinced they have found the first waves ever discovered on a world other than our own. However, these are small, compared to those on our home world. Calculations performed by Barnes and his team show the waves in the image are angled at just six degrees. The winds that caused them were blowing at less than two miles an hour, and the total height of the waves would be just over three-quarters of an inch. The image of the possible waves took up just four pixels on the original image.
There have been some strange readings recorded by Cassini of hydrocarbon reservoirs on Titan. Tides may be able to explain some of those unexpected readings.
It is also possible what Barnes observed are not waves at all, but a wet, solid surface like a mudflat.
Another report, announced the same day, covered a "magic island" in another of Titan's seas, Ligeia Mare. It appeared in one image, then was not visible in a second photograph, taken 16 days later.
"Titan may be beginning to stir. Oceanography is no longer just an Earth science," Ralph Lorenz of Johns Hopkins University, said.
As seasons on Titan change, wind speeds are expected to increase in the north. This could lead to larger, stronger waves near the north pole.
Barnes announced his findings at the Lunar and Planetary Science Conference. While referring to the tiny size of the waves, Barnes told the audience, "Don't make your surfing... reservation for Titan just yet."