Cassini Spots the Sun Shining on Titan’s Sea

Infrared mosaic image showing sunglint off Titan's Kraken Mare. (NASA/JPL-Caltech/University of Arizona/University of Idaho)
Infrared mosaic image showing sunglint off Titan’s Kraken Mare. (NASA/JPL-Caltech/University of Arizona/University of Idaho)

There’s nothing like the beautiful reflection of sunlight off the mirrored surface of a lovely lake… regardless if you’re on Earth or Saturn’s moon Titan! This picture, a mosaic of images acquired by Cassini’s Visual Infrared and Mapping Spectrometer (VIMS) instrument during a flyby on August 21, 2014, shows exactly that: sunglint reflecting off the super-smooth surface of the moon’s largest polar lakes.

(Except unlike on Earth this lake isn’t filled with liquid water but rather liquid methane and ethane!)

Although this isn’t the first time sunlight has been spotted by Cassini reflecting off Titan’s lakes — the last time was in July of 2009 — this is the highest-angle reflection yet, giving a much better resolution image in infrared.

Because the Sun was a full 40 degrees above the horizon as seen from Kraken Mare, nearly twice as high as before, this glint was visible through the haze at much lower wavelengths… down to 1.3 microns.

For a sense of scale, Kraken Mare covers about the same area as the Caspian Sea and Lake Superior put together. (Read more about Titan’s northern lakes here.)

The view above contains real color information although it is not the natural color the human eye would see. Red in the image corresponds to 5.0 microns, green to 2.0 microns, and blue to 1.3 microns. These wavelengths correspond to atmospheric windows through which Titan’s surface is visible. (From Cassini’s vantage point our eyes would see nothing but thick orange haze!)

Read more here on the NASA/JPL news release.

Update: here’s a version of the VIMS image recolored to approximate more natural hues on Titan as our eyes would see them (although we still couldn’t see through Titan’s haze in optical wavelengths from space.) Rotated and cropped: