If the people of Earth ever wanted to make a move on Saturn, next Sunday may seem like a prime opportunity — no rings.
The incredible rings of Saturn are slowly disappearing, at least from our perspective. On March 23, the second-largest planet in our solar system will rise without its rings because of a quirk of celestial positioning.
But don’t worry, Saturn’s “ears,” as Galileo called them, will perk up again soon.
“Next week is when Saturn's rings cross the plane of its orbit with the Earth,” said the University of Wyoming planetarium coordinator Max Gilbraith. “We’ll see them disappear for a few days before and after the equinox, and then they’ll slowly reemerge.”
While that happens for time to time, Saturn’s rings are actually disappearing for good, according to NASA research. And in fact will be gone in about 100 million to 300 million years.
Put A Ring On It
The rings of Saturn are the planet’s most distinctive feature. Jupiter, Uranus and Neptune all have rings, but they pale in comparison to the immensity and intensity of Saturn’s.
“If you were to measure from the outside edge of Saturn’s rings to the center of the planet, it would be roughly 200,000 miles,” Gilbraith said. “That’s the distance between Earth and the moon.”
The rings are composed of 99.9% pure water ice, shattered into particles no bigger than 30 feet in diameter. The rings' age varies, but most astronomers believe they’ve been surrounding Saturn for between 10 and 100 million years.
While the rings of Saturn are incredibly wide, they’re not very thick - less than a mile at the thickest point, and considerably thinner in some spots. If Saturn were scaled to the size of a basketball, the thickness of its rings would be dwarfed by a single human hair.
That’s why the rings will appear to disappear next week. Earth will pass through the plane of the rings, which means Saturn will be positioned so that the rings will be completely on edge from our perspective, creating the illusion of a ringless Saturn.
“The rings are very much compressed into the equatorial region of Saturn,” Gilbraith said. “If Earth had similar rings, they’d look like a weird line in the sky. As you went further north or south, you’d see the rings projected up into the sky out to the same distance as the moon. It’s crazy to think about.”
Saturn’s Ears
Galileo Galilei, the legendary Italian astronomer, was the first person to observe Saturn’s rings with his custom-built telescope in 1610. However, he didn’t recognize them as rings at the time.
“He watched Saturn as it went through the seasons for decades, and noticed how the rings would ebb and flow in size,” Gilbraith said. “He called them the ears of the planet.”
Galileo mused on the disappearing ears when earth passed through the plane of Saturn’s rings in 1612.
"I do not know what to say in a case so surprising, so unlooked for and so novel,” he wrote. "Has Saturn swallowed his children?"
He was even more surprised when “the ears” reappeared in 1613. It wasn’t until 1655, when Dutch astronomer Christiaan Huygens observed Saturn with a more advanced telescope, that Saturn’s rings were identified as rings.
Seeing Spots, Not Saturn
If Galileo could see a ringless Saturn with his telescope, Gilbraith is confident that Wyomingites can observe the curious phenomenon with a basic pair of binoculars. The problem is that Saturn is in a bright spot at the moment.
“Saturn will be very close to the Sun as viewed from the Earth on March 23,” he said. “The separation between the two will be very small, and it would be a helical observation, which means do it right before sunrise."
Looking at the Sun with binoculars is generally not a good idea. Anyone trying at that time will probably want more experience spotting celestial bodies in the sky before attempting it.
"It’s definitely an hour for enthusiasts," Gilbraith said.
The positioning is another quirk of planetary proportions. According to Gilbraith, Earth and Saturn will have a very similar tilt to their axes on the same day, which means they’ve lined up almost opposite each other with the sun between them.
“If you could draw a line between Earth and Saturn, it would almost perfectly go through the sun,” he said. “They’re perfectly aligned, more or less, and it’s fun to see that alignment even if it’s going to be very difficult to do it.”
While the rings will completely disappear the night of March 23, Gilbraith thinks there will still be enough worth looking at in the days before and after. The rings would be perfectly on edge, but they’ll be close enough to look interesting.
“It’s definitely doable for a home observer to see this,” he said. “The timing isn’t the most significant thing for this one.”
13-Year Cycle
Saturn's disappearing rings occur on an observable cycle. The same phenomenon will be visible in October 2038, when Saturn returns to the other side of its tilt.
These cycles prevent windows of opportunities for astronomers who want to learn more about Saturn and Earth. Gilbraith referenced the Cassini–Huygens mission, launched in 1997 to observe Saturn and its satellites.
“We got to see a lot of different angles of the rings and the alignments from Cassini,” he said. “But when Earth passed through the plane of the rings, we got a bunch of new data from Earth that helped us understand the geometry of the rings and their impact on the planet’s climate.”
It turns out the icy rings of Saturn reflect sunlight onto the gaseous surface of Saturn, triggering turbulent storms in its atmosphere. Also, the rings tend to tilt in a different direction every 30 years, increasing their reflectivity.
The rings of Saturn are the planet’s most distinctive feature. That’s exactly why Gilbraith hopes Wyomingites will take a chance to see Saturn while it’s “ringless.”
“Anyone with binoculars or a low-powered telescope can catch Saturn quite well,” he said. “And if you have those tools and a well-trained eye, you can notice the rings change from night to night, just like Galileo did 400 years ago.”
And you better hurry. You may only have a few hundred million years left to see them.
Andrew Rossi can be reached at arossi@cowboystatedaily.com.
