For My Next Trick, I Will Make the Rings of Saturn Disappear

Follow this plan and you can become a celestial magician.

The next time you’re at a party filled with astronomical aficionados – what gala isn’t filled with these types of people? – you can wave a wand, proclaim “abracadabra,” and pull off a parlor trick of planetary proportions.

Well, as long as your party takes place in 2025. Or, if you’re reading this article many years after its publication, in 2038 or 2039.

The subject of your trick will be the body known as Saturn.

The first image of Saturn taken by the James Webb Space Telescope - NASA

Other than Earth, Saturn is likely the most recognizable planet to humans. No knowledge of its size or color is necessary. Its ubiquitous rings identify it immediately, although four planets in our system feature rings! The others – Jupiter, Uranus, and Neptune – have far less impressive rings, to the point that we often barely notice them.

Saturn is the second largest planet in the solar system; its radius is 9.5 times as large as Earth. The gas giant has at least 146 moons, including the second largest in the system – Titan, which is larger than Mercury. Its most famous attribute, however, is the ring. According to NASA, Saturn sports seven major rings, with a smattering of smaller, additional coils. They are primarily formed of water ice.

And they create some incredible visuals.

Saturn imaged by the Cassini Orbiter in 2017 - NASA
A cross-section of the rings taken by Cassini (click on image for larger version) - NASA
Saturn's rings take center stage, as the planet eclipses the sun - Cassini/NASA

The last image above is simply an incredible achievement. The Cassini orbiter caught Saturn eclipsing the sun, leaving the rings brightly illuminated. This photograph is up there on a list of the best visuals we’ve ever encountered.

One could write for weeks about Saturn’s rings, but you didn’t come for a dissertation on the scientific facets of the glorious circles. The magic trick, if you please.

As massive as the system of rings around Saturn is, you can indeed watch as they disappear. And then you can take credit for a trick, just like real magicians. The actual magic is your timing.

The tilting of Saturn - graphic by Tdadamemd
The many angles of Saturn

Saturn, like Earth and Uranus, is tilted with respect to its orbit around the sun. This attribute is known as axial tilt or obliquity, and it’s responsible for seasons. Saturn’s axial tilt is 26.73 degrees, slightly greater than Earth’s 23 degrees. As the hemispheres of Earth tilt closer to and farther from the sun, the amount of light received changes, allowing the different seasons to occur.

Take a gander at the animation above and the views of Saturn’s oppositions in the photo above. Notice the one marked 9/21/2025. The rings of the planet appear to be much smaller than normal. In the animation, one can catch glimpses of positions where the rings seem to blink out of existence or, at the very least, become a flat line. This phenomenon occurs because of Saturn’s constantly changing tilt. Normally, the rings of the planet are either tilted “downward” with respect to our viewpoint, in which case we see sunlight hit the tops of the rings, or “upward” with respect to our viewpoint, in which case we see sunlight hit the bottoms of the rings. When sunlight hits the huge number of particles or bodies in the rings, it makes the rings look solid. In reality, the particles are not huge on an astronomical scale. Every so often, as Saturn cycles through its tilting, we come to a point where we only see the edge of the rings. The sun still lights the rings, but, from our perspective, we only see the width of the constituent particles. Astronomers call this zone the “ring plane.”

From 746 million miles away, the result is a veritable disappearing act.

Saturn from the Hubble Telescope, first tilted, then in the ring plane - NASA

The effect is demonstrated by images taken by the Hubble Telescope in 1994 and 1995. The first snap of Saturn is a normal view; the second was taken during a point in the “ring plane.” Even the most sophisticated telescope of the era could barely discern the rings during this phase. From Earth, your telescope-toting, astronomy partiers will look to the sky and see Saturn without its rings!

In addition to being a neat quirk of timing, Saturn’s ring planes provide scientists with a wonderful window to discover things about the planet. At least 13 of Saturn’s moons were discovered during one of these periods, in addition to a new ring, known as E ring. Normally, the sunlight reflected by the myriad ring particles can obscure all sorts of interesting celestial bodies. When the light just hits the edge, we can distinguish some of the non-ring objects that hide in plain sight. Unfortunately, 2025’s ring plane will likely not yield great discoveries, as Saturn will be too close to the sun. The next one – in 2039 – might produce better results.

The interplay between Saturn and Earth as they both swivel around the sun produces a ring plane approximately every 13 years.

Typically, magicians should not reveal their secrets. However, someone might become rather alarmed to learn that something so large as Saturn could just see a major part of its makeup go poof. Perhaps it’s best to explain the science behind the sleight of celestial hand. After all, other than knowing the timetables of the solar system, you didn’t perform any conjuring antics.

Either way, you’ll be the life of the party, as we all love magicians.

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