Transient features in a Titan sea

• Published in: Nature geoscience Vol. 7; no. 7; pp. 493 - 496
• Main Authors: Hofgartner, J. D., Hayes, A. G., Lunine, J. I., Zebker, H., Stiles, B. W., Sotin, C., Barnes, J. W., Turtle, E. P., Baines, K. H., Brown, R. H., Buratti, B. J., Clark, R. N., Encrenaz, P., Kirk, R. D., Le Gall, A., Lopes, R. M., Lorenz, R. D., Malaska, M. J., Mitchell, K. L., Nicholson, P. D., Paillou, P., Radebaugh, J., Wall, S. D., Wood, C.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.07.2014; Nature Publishing Group
• Subjects: 704/445/242; 704/445/847; Astrophysics; Cassini mission; Dynamics; Earth; Earth and Planetary Astrophysics; Earth Sciences; Earth System Sciences; Equator; Geochemistry; Geology; Geophysics/Geodesy; Hydrologic cycle; Lakes; letter; Methane; Physics; Polar environments; Saturn satellites; Sciences of the Universe; Solar energy; Spacecraft; Summer; Titan
• ISSN: 1752-0894; 1752-0908
• DOI: 10.1038/ngeo2190

As northern summer solstice nears on Saturn’s moon Titan, dynamic processes on its surface are expected. Recent observations by the Cassini spacecraft reveal transient bright features in or on a Titan sea that are consistent with an ephemeral phenomenon such as waves. Titan’s surface–atmosphere system bears remarkable similarities to Earth’s, the most striking being an active, global methane cycle akin to Earth’s water cycle 1 , 2 . Like the hydrological cycle of Earth, Titan’s seasonal methane cycle is driven by changes in the distribution of solar energy 2 . The Cassini spacecraft, which arrived at Saturn in 2004 in the midst of northern winter and southern summer, has observed surface changes, including shoreline recession, at Titan’s south pole 3 , 4 and equator 5 . However, active surface processes have yet to be confirmed in the lakes and seas in Titan’s north polar region 6 , 7 , 8 . As the 2017 northern summer solstice approaches, the onset of dynamic phenomena in this region is expected 6 , 7 , 9 , 10 , 11 , 12 . Here we present the discovery of bright features in recent Cassini RADAR data that appeared in Titan’s northern sea, Ligeia Mare, in July 2013 and disappeared in subsequent observations. We suggest that these bright features are best explained by the occurrence of ephemeral phenomena such as surface waves, rising bubbles, and suspended or floating solids. We suggest that our observations are an initial glimpse of dynamic processes that are commencing in the northern lakes and seas as summer nears in the northern hemisphere.