Star Stuff is a weekly column by rocket scientist & astrophysicist Summer Ash highlighting some amazing things happening every day on and off the planet, especially great science done by and/or for women. She harnesses her science communication powers to smash the patriarchy and advocate for equality and inclusion across all time and space. Throwdowns with pseudoscience may occur.
One month shy of its 20th birthday in space, NASA’s Cassini spacecraft will end, not with a bang or a whimper, but with a blaze of glory to make even Bon Jovi jealous.
Launched October 15, 1997, from Cape Canaveral, FL, Cassini spent its first six years taking the scenic (and gravitationally effective) route to Saturn by way of Venus twice, a return visit to Earth, and a Jupiter flyby. It finally dropped into orbit around the ringed giant on July 1, 2004.
Prior to Cassini, Pioneer 11 and both Voyager spacecraft imaged Saturn on flybys, but with technology from the late 1960s and early 1970s. I’m sure someone, somewhere was prepared for the awesomeness of Cassini’s camera (built more than 20 years later), but it wasn’t me. Not only that, but the range of vantage points the spacecraft got during its various orbital maneuvers enabled it, and therefore us, to see Saturn as never before.
Cassini’s images drive home the point that Saturn is wonderfully absurd. When most people (myself included) see Saturn for the first time through a telescope, they are convinced it’s fake. Your standard backyard telescope can’t resolve Saturn’s cloud bands or its rings, so it looks more like a bright white cartoon version. Your first instinct is to assume someone stuck a paper cutout on the end of the telescope just to mess with you. But they didn’t. The universe is just that creative.
It’s almost impossible to pick Cassini’s greatest hits based on looks alone. Most people end up selecting the images that show something unexpected or objects we’d never seen up close before. But the ones that get me are the ones that are borderline abstract art. They are like a mash-up of cubism, surrealism, and modernism with lines and curves that challenge your sense of perception. It doesn’t help that there’s no up or down in space, but some of these images make it hard to tell even what is relatively up and down, above and below, near and far. Especially when it comes to Saturn’s moons and ring system. You could hang any one of these images in a world-renowned art gallery and they would fit right in. I would even go so far as to say that Cassini is the Ansel Adams of outer space.
Every time I pull one of these images up, I have to catch my breath. Even now, after years of drooling over them, I still have to try and wrap my head around the fact that Saturn actually looks like this.
You seriously can’t make this sh*t up! Plenty of science fiction films have tried and failed, but that old saying “Truth is stranger than fiction” exists for a reason, and that reason is Saturn.
Saturn has a total of 62 known moons, 53 of which have official names, and eight of which were discovered by Cassini. They range in size from the largest, Titan, which is larger and more massive than our own Moon, to less than 10km on the smallest end (half the length of Manhattan). Additionally, evidence points to tens to hundreds of moonlets hidden throughout the ring system, each the size of several football fields or city blocks.
The rings themselves are comprised almost entirely of water ice with a sprinkling of carbon. They are over nine Earths wide, but only 20 meters thick, and the particle sizes range from dust grains to ginormous boulders. For reference, the Cassini spacecraft itself is just under seven meters by four meters, which means it couldn’t venture too close to the rings during its primary mission for fear of damage to its instruments. But that all changed in April of this year, when Cassini was maneuvered into position for its Grand Finale trajectory.
The Grand Finale is a set of 22 passes taking the spacecraft through the gap between Saturn and the inner edge of its rings. This gap is only 2000 kilometers wide, roughly the distance from Seattle to San Diego. The last of these orbits began earlier this month, and the close flyby of Titan on this past Monday nudged the spacecraft just enough to send it plunging into Saturn on Friday morning. Cassini will be science-ing to the very end, sampling Saturn’s atmosphere as it streaks through it at more than 76,000 miles per hour. At that speed, the probe won’t last much more than one to two minutes before it vaporizes, but oh what a couple of glorious minutes those will be.
While there are no concrete plans to return to Saturn just yet, post-Cassini life doesn’t have to be devoid of wonder and awe. You can lose yourself in Cassini’s image archive anytime you like and even try your hand at processing some raw images. I predict you too will be saying “Are you f**king kidding me, Saturn?” before long.