Saturn and Spoked Rings

Saturn is the sixth planet from the sun and the second largest planet in the solar system. This large plant is very unique in the solar system as its chemical makeup is mostly composed of hydrogen and helium. Though this is similar to Jupiter, a fellow gas giant, Saturn is also known for its rings. 

Galileo discovered that Saturn was different from other planets in our solar system in that it had a “ring plane crossing” while other planets did not. At the time the properties of the rings were unknown, there was much to be discovered. In 1655, Christaan Huygens said that these rings were solid and inclined about Saturn’s body. A few years later, astronomers suggested that these rings were composed of multiple satellites. These are natural satellites, such as space dust, meteorites, debris, and other masses in space. Though this theory was confirmed approximately 200 years later, we still have much to discover about Saturn’s rings. 

Researchers have studied Saturn's rings from what they are made of to how fast they travel. Recently, there has been a discovery explored by a photo by NASA’s Hubble Space Telescope in October 2023. It was discovered that Saturn’s rings behave in a phenomenon called ring spokes.  These so-called “spokes” are described as “transient features that rotate along the rings,” according to NASA. When these spokes are active, or visually seen, additional spokes are then created and continue adding to the pattern. Though these do continue to form and grow, the spokes only last two or three rotations around Saturn.  This phenomenon was first discovered in 1981 when NASA’s Voyager 2 first took photos of ring spokes. Later on, Cassini, another NASA orbiter, saw these spokes throughout its mission that ended in 2017. It had been theorized that gravitational fields and other factors may have caused this, but new information was brought to light when Hubble was able to capture the evidence.

Hubble is equipped with Hubble’s Outer Planets Atmospheres Legacy, also known as OPAL, which is a program that monitors weather on all four gas-giant planets. This program has been in place for nearly a decade and continues to provide researchers with important data when researching these larger planets. In studying OPAL imaging, scientists have found that the number and type of spokes differ throughout Saturn’s seasons. Saturn experiences different seasons that each last approximately seven years. Since Saturn is on a tilted axis (approximately 27º), similar to Earth (approximately 23º), these seasons are more pronounced.  As research takes scientists closer to Saturn’s equinox, NASA found that “these ephemeral structures appear on both sides of the planet simultaneously as they spin around.” Though these spokes can stretch to be larger than Earth’s diameter, these appear to be small compared to Saturn’s large structure. Amy Simon of NASA’s Goddard Space Flight Center states, “The leading theory is that spokes are tied to Saturn’s powerful magnetic field, with some sort of solar interaction with the magnetic field that gives you spokes.”

There are many theories as to how this phenomenon is happening. From solar wind to electrostatic forces, Saturn has many exciting properties that will influence the intensity of these spoked rings. 

https://science.nasa.gov/saturn

https://www.cnn.com/2023/12/26/world/hubble-saturn-rings-spokes-scn/index.html

https://www.space.com/23235-rings-of-saturn.html

https://www.sciencedaily.com/releases/2023/12/231221162221.htm