While it’s hard to come up with original words to convey the awe and beauty that is the ringed world Saturn, more words will definitely be needed as a NASA spacecraft sends back its final images this year.
The billion-dollar Cassini spacecraft has spent 12 and a half years orbiting the gas giant with the intricate ring system. And it has revolutionized our understanding of the gaseous globe of Saturn, its 62 moons and, of course those sheets of rings.
Cassini is now beginning a new orbit that will take it a mere 4,000 miles from the edge of the rings and looping over Saturn’s poles once every seven days for three months. And then in April, like threading a needle, the spaceship will plunge into the gap between the planet and rings—a dangerous bonus maneuver where photos and data will be spectacular.
Those planned 22 orbits inside the rings will be the icing on the cake of one of NASA’s most successful interplanetary missions. The sight inside the rings looking out was never imagined when Cassini was launched from Cape Kennedy, Florida on Oct. 15, 1997. But as the original 4-year year mission was extended several times, planetary scientists conceived of a plan to loop the spacecraft over the poles and through the ring gap and planet.
This maneuver will be risky, as the rings consist of millions of gravel-like ice and rock of all sizes sorted out by gravity and controlled by a host of small, “shepherd” moons. Though the space looks empty between the innermost ring and the outer edges of the super cold hydrogen gas of Saturn, there are undoubtedly thousands of stray objects from the size of sand grains to marbles that could rip through Cassini.
The rings are unbelievable. Like grooves on a vinyl record, they are super-thin sheets of rocks and ice that are sifted by size in regions that undulate up and down like rafts on an ocean. They are divided into sections, labeled A-F from the inside out, and the sections have different compositions and the orbital periods vary by distance. They are about 100,000 miles wide on each side of the planet.
But here’s the amazing fact—the rings are around 1,000 feet thick! That is less than a quarter-mile thickness, or the length of three football fields.
To put Saturn’s rings into perspective, hold a business card in your hand edgewise and imagine it is 20 miles wide: that’s the thickness/distance ratio of the rings. Really? Yes, that’s pretty delicate.
So tenuous are the rings that small perturbations in gravity from nearby moons will pull and push the rocky-ice material. There are moons just a mile or so big, that are imbedded inside rings, clearing out small sections.
And, there are actual cliffs rising out of the rings, betrayed by long shadows captured by the cameras of Cassini.
As jaw-dropping as many of the images from Cassini have been, we are in for more scintillating views of Saturn’s rings as the NASA mission comes to a close. In September the spacecraft will be commanded to crash into Saturn, burning up by friction as it flies through the dense gases.
But there will be 300,000 images and hundreds of terabytes of data files to analyze over the next years and decades, no doubt providing more answers to the riddle of the rings.
But understand, in time, we will. As mankind’s nature is to explore and satisfy our curiosity about who we are and where we live.
For more Saturn images, visit the official site: the Cassini Imaging Central Laboratory for Operations—www.ciclops.org.