Saturn’s Ring Will Be Gone In 292 Million Years

  • Saturn’s ring particles are flowing into the planet at the rate of 432 – 2870 kilograms per second. 
  • At this rate, the rings will be gone in less than 300 million years. 

The rings of Saturn make the 2nd largest planet a standout in our solar system. They contain countless small particles, ranging from micrometer to meter in size, orbiting Saturn. Most of these particles are made of water ice with traces of rocky material.

There are total 6 rings – the biggest ones span 273,588 kilometers in diameters. They are not perfect circles, but instead contains several bends caused by the gravitational pull of nearby moons.

Recently, NASA has confirmed that Saturn is losing its ring at faster rates than previously thought. In fact, the data obtained from Voyager 1 and Voyager 2 space probes indicate that the planet is currently losing its rings at the maximum rate.

Where The Rings Are Going Exactly?

All 6 rings are being pulled into the Saturn (at different rates) by gravity. More specifically, the rings are flowing into the Saturn’s ionosphere along magnetic field lines. The flow rate is somewhere between 432 and 2870 kilograms per second – mostly to the south. At this rate, the rings will be entirely gone in 292 million years.

But how these rings came into existence: did rings form with the Saturn or did they come later? The recent findings favor the latter situation, suggesting that the rings are nearly 100 million years old (Saturn is over 4.5 billion years old). Currently, they are in the middle of their lifetime.

No one knows how these rings were formed, but if the planet acquired them later in life, they could have formed due to the collisions of small, icy moons that orbit Saturn (millions of years ago). Perhaps orbits of those moons were distorted by a gravitational pull of a passing comet or asteroid.

According to the researchers, we’re quite lucky to witness Saturn’s ring system. And, if it’s temporary, perhaps we just missed out on observing massive ring systems of Neptune, Uranus, and Jupiter, which contain only faint and thin ringlets today.

Reference: ScienceDirect | doi:10.1016/j.icarus.2018.10.027 | NASA

Saturn’s gravitational pull tries to draw ring particles back into the planet, while particles’ orbital velocity tries to fling them outward into space. Thus, rings are currently caught in a balancing act between these two forces.

Plasma clouds emitting from micrometeoroid bombardment of the rings and UV light from the Sun can electrically charge small particles within the rings. Once particles acquire electric charge, they can be affected by Saturn’s magnetic field.

When this happens, the balance of two forces on those charged particles changes significantly, and particles get dragged into the planet along magnetic field lines.

After getting into the Saturn’s upper atmosphere, these particles vaporize and water reacts with the ionosphere. This kind of reactions increases the lifespan of H3+ ions (made of 2 electrons and 3 protons), which glow in infrared rays.

Saturn's Ring Will Be GoneImage credit: Goddard Space Flight Center / David Ladd / NASA

Astronomers observed these glowing H3+ ions using Keck telescope in Hawaii. They were able to observe glowing bands (shown in blue) in planet’s southern and northern hemispheres, which showed the amount of ring particles entering the planet along the magnetic field lines.

Read: 15 Interesting Facts about Saturn

In the future, the team will observe how the rate of flow of ring particles changes. Saturn’s orbital period is 29.45 years: as it progresses in its orbit, its rings are exposed to varying degrees of sunlight, which would alter the quantity of ring particles entering the planet.

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