Prometheus Slices Through Saturn’s F Ring


Saturn’s moon, Prometheus, looks similar to a sickle and is cutting its way through Saturn’s F ring. Prometheus’ orbit sometimes takes it into the F ring. When this occurs, it slices right through it, causing a gravitational disruption that clears some of the smaller particles within the F ring. There are dark lines inside the F ring’s bright core under Prometheus, showing there have been previous ring-moon interactions, as seen in the image below.

PrometheusThe Cassini space mission includes NASA, the ESA (European Space Agency), and the Italian Space Agency. The Jet Propulsion Laboratory (JPL) is the division of the California Institute of Technology that manages the Cassini mission for the NASA Science Mission Directorate. The Cassini orbiter has two cameras onboard that were designed, assembled, and developed at JPL. The operations for the imaging center is are located at the Space Science Institute in Boulder, Colorado.

The many iced-over moons that orbit Saturn are dramatically different from each other. They have different sizes, shapes, and origins, and their surfaces are of different ages. Some of the moons are covered in fine, icy particles, and others have rough, hard surfaces. The moons have different-sized craters, and some have valleys and ridges. Dione and Tethys have even shown evidence of tectonic movement.

Saturn’s rings spread out over hundreds of thousands of kilometers, however, the rings are extremely thin. Saturn’s rings, about 10 meters thick, are made up of particles of ice and water that make wakes, waves, and other structures. The name of the rings, in order, as they are moving away from Saturn, are D, C, B, A, F, G, and E. There are many more rings that do not have names because they are very faint, due to being made from icy, fine particles.

Scientists do not know how old Saturn’s rings actually are. The rings could have always been part of the solar system, or they could have been formed over time. This is currently being investigated by Cassini scientists.

Regardless of when the rings were formed, scientists are sure that the rings of Saturn, as they are observed today, were not each created in the same way. Cassini’s cameras have shown that a significant swell of icy material exploded from the moon Enceladus. Enceladus is responsible for the material that created the E ring. The Cassini orbiter has observed that Saturn’s inner moons orbit within complete or partial rings that have been formed by particles that broke free from the moon’s surfaces as they bounced off micrometeoroids.

Prometheus is a shepherding satellite that is supposed to be constricted to the orbit that is the inside edge of the F ring. Prometheus has visible craters, with some of them measuring 20 kilometers in diameter and with irregular shapes, but it does not have as many craters as Janus, Pandora or Epimetheus. Prometheus is low in density and is believed to have a porous and icy body. Despite its makeup, Prometheus shows the marks it has left behind as it slices through the F Ring of Saturn.

Saturn’s moons were named after Greco-Roman Titans and their descendants. However, so many moons were discovered by scientists that they began to name the moons after gods from other mythological stories, such as Inuit, Gallic, and Norse tales. Prometheus was the son to Iapetus, the Titan and brother of Atlas and Epimetheus. Prometheus is best known for stealing fire from the gods for humans, according to Greek mythology.

Saturn has many moons, but Prometheus is one of the smallest. Prometheus was discovered in 1980 during Voyager 1’s flyby of Saturn. At this moment, Saturn is known to have 62 moons.

PrometheusThe F ring cannot be seen from a standard backyard telescope, and was first seen in 1979 by the Pioneer 11 spacecraft. On March 25, 2015, Cassini took a picture of the triple crescents of Mimas, Titan, and Rhea. In 2004, Cassini was sent into Saturn’s orbit. It will explore the planet until it burns up in Saturn’s atmosphere in the year 2017.

Prometheus’ oblong body is 53 miles across, which is the same distance as its orbit, and often slices through the particles of ice that create the F ring of Saturn. This slicing action is well-known, however, NASA released an image taken by the Cassini spacecraft in March. The dark cuts in the ring are amplified.

By Jeanette Smith


NASA: Ring Slicer
NASA: Cassini Solstice Mission: About Saturn & Its Moons
Sen: Cassini Spies Icy Moons of Saturn

Top Image Courtesy of NASA’s Marshall Space Flight Center’s Flickr Page – Creative Commons License
Second Image Courtesy of NASA’s Marshall Space Flight Center’s Flickr Page – Creative Commons License
Third Image Courtesy of NASA’s Marshall Space Flight Center’s Flickr Page – Creative Commons License
Featured Image Courtesy of Brett Jordan’s Flickr Page – Creative Commons License

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