The popular conception of Saturn is virtually inseparable from its majestic rings. But in a little over a year, skywatchers won’t be able to see these iconic structures: In 2025, Saturn’s rings will be invisible from Earth for several months.
Fortunately, this isn’t a sign of a planetary apocalypse. Rather, it’s a matter of simple physics.
“While it’s true the rings will become almost invisible from Earth in 2025, this is neither a surprise nor reason to panic,” Jonti Horner, an astrophysicist at the University of Southern Queensland in Australia, writes in the Conversation.
Why won’t Saturn’s rings be visible?
In reality, it all has to do with planetary alignment. Saturn’s rings are so thin that they seemingly vanish when viewed edge-on. And as Earth and Saturn travel around the sun on their respective orbital paths, our planet reaches this particular vantage point like clockwork, roughly every 13 to 16 years.
As Saturn completes its orbit over approximately 29.4 Earth years, it leans at an angle of 26.7 degrees. This means that our view of Saturn toggles between the upper side of its rings when it’s tilted toward us and the lower side when it’s tilted away. We get the special, ringless view of the planet when Earth transitions between each of these perspectives and passes through Saturn’s “ring plane,” essentially, any area of space that’s in line with the edge of its rings.
From that angle, “they reflect very little light and are very difficult to see, making them essentially invisible,” Vahe Peroomian, a physicist and astronomer at the University of Southern California, tells CBS News’ Caitlin O’Kane.
In May 1995, Earth crossed through Saturn’s ring plane, and the Hubble Space Telescope captured an image of the gas giant with its rings looking paper-thin. Then, the phenomenon happened again in 2009.
This time, the rings will disappear from sight in March 2025. “They’ll gradually come back into view as seen through large telescopes, before sliding out of view again in November 2025,” writes Horner. “Thereafter, the rings will gradually get more and more obvious.”
Opportunities for science
Getting this rare view of Saturn is a special chance for researchers to learn more about the planet. Astronomers discovered at least 13 moons of Saturn during ring plane crossings in history, including the well-known Titan, Enceladus and Mimas, the “death star” moon. (Now, the planet is known to have 146 moons, the most in the solar system.)
In 1966, scientists spotted Saturn’s E ring for the first time during one of these events. This diffuse ring is the outermost of the planet’s seven—named alphabetically in the order they were discovered—and it can only be seen at ring plane crossings.
With the upcoming crossing in 2025, however, conditions will be less than favorable for observing the planet. Just as it was in 2009, Saturn will appear, from our perspective, very close to the sun in the sky, largely obscured by the light of the star.
For a truly clear view of Saturn “without” its signature rings, skywatchers and scientists will have to wait until 2038 and 2039, which will have three ring plane crossings.
And for the best view of the planet alongside its most iconic feature, observers can look up in 2032, when Saturn will be tilted 27 degrees away from us, displaying the lower side of its rings at peak visibility.
Saturn’s real disappearing act
Even though we briefly won’t be able to see them, Saturn’s rings aren’t going anywhere in the immediate future. But on a greater, cosmic timescale, the planet’s bands of ice and rock might really be on their way out, according to recent studies.
In May, researchers examining old data collected by the Cassini space probe suggested that Saturn’s rings are much younger than thought—they might have materialized in just the last 400 million years. Compared to the 4.5-billion-year history of Saturn, that makes the rings quite new.
But despite their young age, the rings might be more than halfway through their existence—the researchers suggested these structures could be gone in another 15 million to 400 million years.
The driving force of Saturn’s ring loss is a phenomenon known as “ring rain.” Astronomers first coined this term in the 1980s, but then, for decades, it was largely forgotten. The idea—that suggests bits of the rings are falling into the planet—began to gain traction again in 2013.
This year, researchers suggested that meteoroids play a role in causing this “rain,” bombarding the objects orbiting Saturn and eventually sending them down into the planet, where they become snared by its gravity.
Scientists calculated the rings are losing between 952 and 6,327 pounds of water per second—or roughly enough to fill an Olympic-size swimming pool every 30 minutes.
Though we often think of Saturn as the “ringed planet,” it is really one of four in our solar system with a celestial halo—Jupiter, Uranus and Neptune are also encircled. But knowing how Saturn’s rings are withering away, scientists have suggested that these other planets’ rings, which are currently darker and less pronounced, may have one day been as splendid as Saturn’s, before the forces of “ring rain” wore them down.
Yes, Saturn’s rings will likely be gone in the distant future, but the way many astronomers see it, humans experienced a real stroke of cosmic luck to have evolved during the ephemeral period where we can marvel at them. Even if they disappear from sight every once in a while.