Shoreline of Ancient Titan Sea This image from NASA's Cassini
spacecraft shows an ancient southern sea that used to sprawl out
near the south pole of Saturn's moon Titan. In an annotated
version, the red outline traces the ancient shoreline. Within
this basin is the largest present-day lake in Titan's southern
hemisphere, Ontario Lacus. Ontario Lacus appears black,
indicating it is filled with liquid. This image was obtained by
Cassini's radar instrument on July 2009 and January 2010.
Several images have been stitched together. By analyzing these
images, scientists estimate the ancient sea was possibly as
large as 300 by 170 miles (475 by 280 kilometers) across and
likely less than a few hundred feet (meters) deep. Ontario Lacus
is about 80 by 235 kilometers across, and probably at least 30
feet (10 meters) deep at its center. Seas may have covered large
parts of the southern hemisphere less than 50,000 years ago.
Titan, Saturn’s largest moon, is the only place besides Earth in
our solar system that hosts lar