Newly released imagery from the Cassini spacecraft shows just how cool the giant planet's rings really are.
The false-color reading is color-coded to reflect temperature data from Cassini's Composite Infrared Spectrometer. In its description of the imagery, NASA said Thursday that the data represents "the most detailed look to date at the temperature of Saturn's rings."
Red represents temperatures of 261 degrees below zero Fahrenheit (110 degrees Kelvin), and the blue areas are even colder — minus-333 degrees F (70 degrees K). Green is equivalent to minus-298 degrees F (90 degrees K). The Kelvin temperature scale is used to measure very cold substances; zero corresponds to absolute zero, and the freezing point of water is 273 degrees K.
The readings show that the opaque region of the rings, like the outer A ring (on the far right) and the middle B ring, are cooler, while more transparent sections, like the Cassini Division (in red, just inside the A ring) or the inner C ring (shown in yellow and red), are relatively warmer.
The temperature data were taken on July 1, looking at the unlit side of the rings. In order to show the full breadth of the rings, a strip of temperature data was mapped onto a picture of the lit side of the rings taken with Cassini's narrow angle camera on May 11, a little more than a month before Saturn orbit insertion.
In this picture, Saturn is overexposed and thus is nearly pure white. Saturn's moon Enceladus is visible as a mere speck below the rings, toward the center. (You can see the original black-and-white picture at NASA's Planetary Photojournal.)
The $3.3 billion Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA. The Cassini orbiter was designed, developed and assembled at JPL. The Composite Infrared Spectrometer team is based at NASA's Goddard Space Flight Center in Greenbelt, Md.