These three images, created from Cassini
Synthetic Aperture Radar (SAR) data, show the appearance and evolution
of a mysterious feature in Ligeia Mare, one of the largest hydrocarbon
seas on Saturn's moon Titan. Image credit: NASA/JPL-Caltech/ASI/Cornell. Full image and caption - (Images of the feature taken during the Cassini flybys)
NASA's Cassini spacecraft is monitoring the evolution of a mysterious
feature in a large hydrocarbon sea on Saturn's moon Titan. The feature
covers an area of about 100 square miles (260 square kilometers) in
Ligeia Mare, one of the largest seas on Titan. It has now been observed
twice by Cassini's radar experiment, but its appearance changed between
the two apparitions.
The mysterious feature, which appears bright in radar images against
the dark background of the liquid sea, was first spotted during
Cassini's July 2013 Titan flyby. Previous observations showed no sign of
bright features in that part of Ligeia Mare. Scientists were perplexed
to find the feature had vanished when they looked again, over several
months, with low-resolution radar and Cassini's infrared imager. This
led some team members to suggest it might have been a transient feature.
But during Cassini's flyby on August 21, 2014, the feature was again
visible, and its appearance had changed during the 11 months since it
was last seen.
Scientists on the radar team are confident that the feature is not an
artifact, or flaw, in their data, which would have been one of the
simplest explanations. They also do not see evidence that its appearance
results from evaporation in the sea, as the overall shoreline of Ligeia
Mare has not changed noticeably.
The team has suggested the feature could be surface waves, rising
bubbles, floating solids, solids suspended just below the surface, or
perhaps something more exotic.
The researchers suspect that the appearance of this feature could be
related to changing seasons on Titan, as summer draws near in the moon's
northern hemisphere. Monitoring such changes is a major goal for
Cassini's current extended mission.
"Science loves a mystery, and with this enigmatic feature, we have a
thrilling example of ongoing change on Titan," said Stephen Wall, the
deputy team lead of Cassini's radar team, based at NASA's Jet Propulsion
Laboratory in Pasadena, California. "We're hopeful that we'll be able
to continue watching the changes unfold and gain insights about what's
going on in that alien sea."
The Cassini-Huygens mission is a cooperative project of NASA, the
European Space Agency and ASI, the Italian Space Agency. JPL, a division
of the California Institute of Technology in Pasadena, manages the
mission for NASA's Science Mission Directorate, Washington. The radar
instrument was built by JPL and the Italian Space Agency, working with
team members from the United States and several European countries.
For more information about Cassini and its mission, visit: http://www.nasa.gov/cassini - http://saturn.jpl.nasa.gov
Preston Dyches
Jet Propulsion Laboratory, Pasadena, Calif.
818-354-7013
preston.dyches@jpl.nasa.gov
Source: JPL - Caltech
