Saturn’s Rings Could Be Younger Than Flowers

The Cassini spacecraft had been in operation much past its initial four-year mission by the time it reached the end of its lifetime in orbit around Saturn in 2017. Before entering Saturn's atmosphere as directed, it had been extended for two years, then for seven, and had spent 13 years observing Saturn, its moons, and its ring system. As it did, it left 13 years' worth of data in our care, many of which still contain numerous undiscovered riches.

While we can all agree that the complex ring system encircling the planet is beautiful, one of the most basic problems regarding Saturn seems to be: They have been there for how long?

They aren't more than 400 million years old and may even be less than 100 million years old, according to a recent Science research, which adds to a growing body of data. If they are less than 100 million years old, this would place the formation of Saturn's rings in the midst of the Cretaceous epoch on Earth, while 400 million years would advance us to the time when the progenitors of the contemporary shark and the first trees arrived on land.

Despite the rings' age, there are a few things we know for sure. The rings are dispersed across a huge surface area and are only sometimes 20 meters thick. They are likewise largely composed of pure water ice. The rings are made up of around 98 to 99.9% water ice by volume and more than 95 percent distinct ice pieces by mass. Furthermore, we are aware that there is a continuous shower of extremely small ice and rock particles between the planets that we might just as readily refer to as "dust."

The assumption is that since the rings are 95 percent water ice by mass presently and have been repeatedly pelted by grit that is not ice, they must have once been 100 percent pure water ice. Although it is improbable that Saturn's rings have ever truly been made entirely of water ice, putting this assumption places a time limit on their potential existence. The amount of interplanetary dust that has been pelted upon the rings must be estimated at this time; the more quickly the dust collects, the younger the rings must be to still be so brilliant and frosty. Looking at the snow along the edge of a road in this way is extremely technical; if it is new snow, it will appear sparkling white. However, given enough time or traffic, dirt from the road will mix with the snow, darkening it and turning it into a mound of considerably less appealing frozen muck.

After the fact ring formation requires a catastrophic event.

This estimate was precisely what Cassini was able to offer. The Cosmic Dust Analyzer, which was on board Cassini, was primarily made to determine the chemical make-up of the particles it met, gauge their sizes, and determine their direction and speed of motion before being caught. An estimation of the journey that the particle of dust had travelled to get to Cassini is possible using the direction and speed together. Most frequently, they seemed to be drifting toward Saturn from the Kuiper Belt, a ring of ice objects surrounding the sun just beyond the orbit of Neptune. Many of the dust particles turned found to be falling inward from outside of Saturn's gravitational field. The important micrometeorites, which are the dust grains that have been found, are generally micron-sized particles that are smaller than a single red blood cell.

You may calculate the amount of time it would take to transition from a pure, pristine ring of water ice to one that is "polluted" to its current form by considering the pace at which Cassini encountered these micrometeorites and the mass of those particles. One other supposition used in this computation is that the micrometeorites also include a significant amount of ice, meaning that only 10% of their mass is really increasing the non-ice component of Saturn's rings. The rings may be much younger if that proves out to be an underestimation and the dust is truly rockier than that. Based on the observed speed of the incoming particles, there are also certain estimates regarding how much of the ring mass melts away with each collision.

The rings could only be 400 million years old before they would have to be made entirely of water ice, based on all of these observations and presumptions combined, and utilizing just the particles that Cassini encountered and about which the study team felt quite positive that they originated from outside Saturn. The age estimate reduces to 100 million years if they include all the extra dust that they believe to be very likely to have come from outside Saturn. The rings of Saturn are thus younger than blooming plants.

Saturn's rings are young, indicating that the planet itself did not originate with the rings; Saturn formed with the other main planets in the solar system about 4.5 billion years ago. After the fact ring formation requires a catastrophic event. Maybe an ice-rich moon wandered too near to Saturn some 100 million years ago. Saturn's gravity would have been able to stretch that unfortunate moon until it shattered, splitting into several fragments, like a far more powerful version of Earth's tides. After all, Mimas' mass is just 40% that of Saturn's rings, therefore a single moon that broke apart would be sufficient. Alternatively, it might have been two moons that collided, killing both of them.

When Saturn has rings, the solar system is at its most amazing. These rings have shown us that they are feasible, that we should search for them on other planets, and that we should appreciate their fleeting beauty.