This artist concept shows a mirror-smooth lake on the surface of the smoggy moon Titan.

This artist concept shows a mirror-smooth lake on the surface of the smoggy moon Titan.

Altimetry Over Ontario Lacus

Cassini streaked past Titan on Dec. 21 at an altitude of 971 kilometers
(603 miles), obtaining radar images of Titan's south polar region and a
topographic profile of the dark, possibly liquid-filled area known as
Ontario Lacus.