Although it might look like a bit of smudgy celestial mischief, neither Pandora nor any of Saturn’s other moons is to blame for a recent disruption of one of the planet’s rings, according to NASA. Considering that the gas giant has 53 moons in orbit (and nine other moons awaiting confirmation), scientists monitoring NASA’s Cassini spacecraft were curious.
Using a visible light narrow-angle camera in April, the Cassini spacecraft — which has orbited Saturn since 2004 — captured a view of the disruption. It was caused by what’s known as a “jet” — the interaction of a small object embedded in the ring itself and material in the core of a ring. Though the individual objects embedded in the rings are hard to see, their activities are more visible, which is one of the ways Cassini has opened our eyes to the mysteries of this outer planet.
This particular event was photographed 1.4 million miles from Saturn.
Our solar system’s gas giants, Jupiter, Saturn, Uranus and Neptune, are made up mostly of hydrogen and helium. They have rings made of ice and rock chunks that are the remains of shattered comets, asteroids and moons. Even though Saturn is known for its seven rings, which orbit at different speeds and span up to 175,000 miles, NASA’s Voyager missions in the 1980s discovered that there are thousands of complicated braided rings, ringlets and spokes within the ring system. The billions of particles in this system can range from tiny ice grains to mountain-size particles.
Two small moons, Daphnis and Pan, orbit within the Encke and Keeler Gaps in the rings. Their orbits help keep the gaps open and sweep excess materials out of them, like rocks in a stream. Moons like Prometheus act like shepherds and keep the rings in line by constraining them, but others like Pandora (seen in the lower right portion of the photo above) are troublemakers that disrupt the rings.
The Cassini mission, which ends in September 2017, has been exploring the planet and its moons, rings and powerful magnetosphere. During the planet’s autumnal equinox in 2010, the sun shone on the rings, enabling Cassini to collect exciting insights about their composition.
The seven rings are named alphabetically, A through G, in the order that they were discovered. In order to enter the planet’s orbit, the spacecraft did a delicate dance through the F and G rings.
Saturn is about 900 million miles from the sun, which is nearly 10 times as far as our own distance from the star. While a day on Saturn takes only about 10.7 hours, a year lasts the equivalent of 29 on Earth. And this gas giant has a volume that’s a hulking 700 times that of our own planet.
Saturn’s current alignment is in a straight line with the sun and Earth (with Earth in the middle), which affords us a great view of the planet and even some of its moons. Using a telescope, you can see even more moons and Saturn’s rings tilted at 26 degrees.