Posted on June 3rd, 2014

Reaching Orbit – Cassini

SaturnThis stunning view of Saturn was mosaiced from 165 images taken by the Cassini spacecraft as the planet was blocking the Sun. The image is a composite of ultraviolet, infrared and clear filter images that were then manipulated to appear in natural color. (Credit: NASA/JPL/Space Science Institute)
EnceladusWhile this appears to be a computer animation, it is actually an image of Enceladus from Cassini’s narrow-angle camera capturing images in the visible spectrum. (Credit: NASA/JPL-Caltech/Space Science Institute)
PanSaturn’s moon, Pan, creates a gap in the planet’s A ring, hundreds of kilometers in size. (Credit: NASA/JPL-Caltech/Space Science Institute)

Saturn is a pretty amazing planet, very different than any other planet in our solar system. It’s so interesting that NASA instigated the Cassini mission to explore Saturn from orbit, along with its moons and rings. Cassini has made many significant discoveries, including determining the depth of the Titan Sea. Titan is the largest moon orbiting Saturn, and it is of great interest due to the presence of liquid on its surface – the only other body in our solar system to have something similar is our Earth. Normally radar data wouldn’t be able to penetrate liquids like water, but Titan’s lakes are composed mostly of methane and ethane, allowing for its depth of 560 feet to be measured using this technology.

Saturn’s most notable feature is its rings, and while they spread hundreds of thousands of kilometers, further then the distance between Earth and our Moon, they are remarkably thin. In some instances the rings may only be 10 meters thick. The particles orbiting the planet don’t create just one large ring, instead they are grouped together into main ring sections based on their composition and characteristics.

For instance, the ring furthest away from the planet, called the E ring, is believed to be the product of ice particles spewing from the moon Enceladus. While the surface of the moon is estimated to be about -330 degrees Fahrenheit, there is a hot spot at the moon’s south pole, where water vapor and ice particles are ejected, begging the question of whether there is liquid water on the moon that could harbor life. Another interesting discovery is that the polar activity is more prevalent when the moon is orbiting further away from Saturn and is less active when it swings closer.  One hypothesis is that the fissures, where the particles are being ejected, are squeezed shut by the force of Saturn’s gravity. All of this was discovered by the Cassini spacecraft and its many sensors, and up until that point, it was believed that Enceladus was a dead, icy moon with no subsurface activity.

Enceladus is just one of dozens of moons that orbit Saturn and Titan is the most famous of these, however Pan is also a very interesting satellite. Pan is the moon that orbits closest to Saturn, so close it bisects Saturn’s A ring, creating the Encke Gap that is 325 kilometer wide. The moon creates waves in the particles orbiting closer to the planet; and since they are traveling at faster speeds, these waves intersect further into the ring and become bunched up, making wakes.

The more we discover the more questions we have. Cassini has found new ringlets, moons and materials floating in the rings that resemble straw and rope features also present on some of its moons. Cassini continues to make amazing Saturn discoveries but there is still so much that is unknown about this fantastic planet.

Katie Nelson
Geospatial Ninja
(303) 718-7163

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