Will Saturn’s rings disappear? it depends on your point of view

Saturn’s rings are disappearing, but they will return someday

Written by Phil Preit Edited by Lee Billings

I recently noticed something strange about Saturn as I was looking at it near Venus shining in the southwest night sky. Objects close to our evil twin sister planets look somewhat dull by comparison, but while Venus can sometimes be bright enough to be mistaken for an airplane or a UFO, Saturn was decidedly gloomy. It is now somewhat dimmer than normal because it is almost on the opposite side of the Sun from us and at about its maximum distance from Earth. But still, it looked particularly dim.

Then I remembered that Saturn’s glorious rings are disappearing — at least from our vantage point here on Earth. The usually wide ring now appears much thinner than usual, almost like a line across the globe. Without the countless reflective ice masses that add to the glow we see from Saturn, Saturn’s actual brightness is less than half that at other times of the day.

Rest assured, Saturn’s magnificent rings are still there. There are two reasons why they are virtually invisible. One, they are almost inconceivably flat, and two, our viewing angles are affected by the movements of Saturn and Earth’s respective orbits.

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Saturn’s rings are not only the most obvious structures on Earth, they are probably the most spectacular structures in the entire solar system. The main ring is approximately 280,000 kilometers in diameter. If you put them between the Earth and the Moon, they would cover more than two-thirds of that gap. Saturn’s rings, which are more than 1 billion kilometers from Earth, are invisible to the naked eye, but they are barely visible. As soon as we started examining the sky with telescopes, the rings were discovered. If their real structure remains a mystery.

Galileo observed the rings with a crude telescope in the early 17th century, but the resolution wasn’t high enough to see their true shape, so he called them Saturn’s “ears.” Decades later, Dutch astronomer Christiaan Huygens noticed that the planet was surrounded by a ring that “touched nowhere,” as he wrote in his book. Systema Saturnium. None other than James Clerk Maxwell, the physicist who determined the equations of electromagnetism that underpin our technological civilization, believed that such a ring could not be solid or it would fall apart. He was the first person to prove that. The inner edge would rotate around Saturn much faster than the outer edge and shred Saturn. This tells us that the planet’s rings must be made up of clumps of material too small to be seen with telescopes from Earth. More recent observations have shown that these chunks are almost pure water ice. That’s why they are so bright. Ice is an excellent reflector of sunlight. And the latest research also shows that most of these blobs are smaller than the average car. There should be A thousand trillion Of them.

This ring was probably formed by the collision of Saturn’s icy moons. difficult, By an incoming celestial body, perhaps another moon as well. Interestingly, it is not clear when this happened. Research published in journals Icarus In 2023, a study of the accumulation rate of dark micrometeorite dust on an otherwise glowing ring showed that the ring was cosmically young, only 100 million to 400 million years old. It turned out. On the other hand, a study published in a journal at the end of 2024 natural earth science It turns out that the rate of “contamination” from this dust is not as fast as thought. High-velocity collisions with micrometeorites ionize the ring particles, giving them an electrical charge. This makes it susceptible to Saturn’s strong magnetic field, which pushes matter away and slows the rate at which the rings darken. That means the ring could be much older.

Even today, centuries after its discovery, this ring remains a fundamental mystery.

Still, how they formed after the first impact is relatively well understood, explaining their flatness, if not age. The orbital motion of Saturn’s moons and their impactors may have initially formed long streams of debris, most of which lay in the direction of the moon’s orbital motion. Because Saturn’s other moons orbit around the equator, material from this moon may have had a similar composition. Also, because Saturn is not a perfect sphere and bulges out near the equator due to its rapid rotation period of 10.5 hours, Saturn’s thickened center may have screwed the debris into an orbit directly above the equator. This is why the shock that produced the ring formed a flat disk.

and what i want to say is flat. Despite its diameter being hundreds of thousands of kilometers, the ring very It is thin and extends vertically no more than 1 kilometer. In some places, the ring is only 10 meters high, as tall as a three-story building. The rings are huge, but if the rings and Saturn itself were reduced to the length of a standard piece of paper, 28 centimeters (11 inches) in diameter, the rings would be 100 times thinner than paper. Finally, gravitational interactions with Saturn’s large moons pull these ring particles into slightly different orbits. Over time, they created thousands of individual rings and several gaps between them. Viewed from above, the ring is therefore a source of slack-jawed awe. However, when viewed from the side, it is very thin and very difficult to see.

That’s what we’re finding now. Saturn, like Earth, has a large axial tilt of more than 26 degrees from the ecliptic plane in which all major planets revolve. (Earth is tilted 23 degrees.) This means that during Saturn’s northern summer, Saturn’s north pole tilts toward the sun. From Earth, which is much closer to the Sun than Saturn, we will be able to “look down” on the rings and see them in all their glory.

Because Saturn’s orbital period is only about 30 years, we can clearly see its rings for most of Saturn’s year. However, during Saturn’s equinoxes, the rings appear more edge-on from Earth, which is what they actually look like. that’s right Edge on as seen from the sun. However, because Saturn’s orbit around the Sun is only slightly tilted compared to Earth’s orbit, we only see the exact edges of the rings at Saturn’s equinoxes when the Earth passes through the plane of the rings. . This can occur twice near the vernal equinox when the Earth passes “upward” through the plane and again “downward” about 6 months later, effectively turning Saturn’s rings into erased from our sight.

And Saturn’s autumnal equinox happens to occur in May 2025. And on March 23rd, our planet will pass through the ring plane. At that time, the ring reaches the peak of its disappearance, and then slowly returns to sight.

However, there are some caveats. On that day in March, Saturn will be only 10 degrees from the Sun in the sky, making it extremely difficult to observe. Bad timing! Saturn will pass through Earth’s orbit again in mid-November, but by then the tilt of Saturn’s axis will have tilted the rings slightly from our perspective, so all we can see is It will be just them. largely Edge on. The good news is that in November, Saturn will be easily visible in the southern sky after sunset and will still appear to have almost no rings when seen through a telescope. Check to see if your local astronomical observatory or astronomical society is holding an observation party!

I would like to investigate it myself. Saturn without rings is very strange and something I haven’t seen in over 7 years. But I’m also looking forward to the Earth becoming brighter again as time progresses and those glorious rings re-emerge. Somehow without them Saturn wouldn’t be Saturn.