Titan is the only moon in the solar system to host a significant atmosphere—a roiling haze of organic molecules, which some scientists think might include the ingredients for life as we know it.

It's also the only object in the solar system, other than Earth, to have bodies of liquid on its surface—previous data from NASA's Cassini orbiter revealed hundreds of lakes near the frigid moon's poles.

With surface temperatures hovering around -297 degrees Fahrenheit (-183 degrees Celsius), Titan is far too cold to have liquid water. Instead, the lakes are filled with liquid hydrocarbons, such as methane and ethane.

(See "Methane Rain Formed New Lake on Saturn Moon.")

Now, for the first time, Cassini images show dark regions that appear