Saturn's moon Pan has a shape. Saturn's satellite turned out to look like a flying saucer. How did the satellite Pan get its name?

Publication date: 14.03.2017

The space agency NASA has published several new images of Pan, a tiny moon of Saturn. The images were taken on March 7, 2017 by the Cassini space probe from a distance of about 24 thousand kilometers. We see a “moon” of a bizarre shape, which is very similar to a huge dumpling flying in space - or a nut, if you like.

Pan, Saturn's inner moon, also known as Saturn XVIII, was discovered in 1990 by Mark Showalter in Saturn's rings while analyzing photographs taken as early as 1981. Pan received his name in honor of the famous mythological creature.

By dumpling standards, Pan is huge, but by astronomical standards he is just tiny. Its maximum size is about 35 kilometers. It is the second most distant moon of Saturn and is located in the gap between Saturn's rings. Pan is a “shepherd” satellite (or “vacuum cleaner”) - acting with its gravity, it clears the surroundings of its own orbit from ring particles. Pan makes a full revolution around Saturn in less than 14 hours.

Experts have not yet agreed on why Pan has this shape.

Images by NASA/JPL-Caltech/Space Science Institute.

And here are the same pictures, stitched together into an animated GIF file:

We live in amazing times, don't we? You launch your camera into who knows what cosmic distance and discover that Saturn’s satellite is a literal dumpling.

The American Cassini spacecraft, completing its mission near Saturn, has once again proven that for amazing discoveries it is not at all necessary to fly to other stars, and the amazing is still somewhere nearby - in our still little-studied solar system. You just have to look closely.

Just three days ago, on March 7, the device managed to photograph with unprecedented clarity one of Saturn’s many moons—tiny Pan.

Carolyn Porco/NASA

And although scientists had previously guessed about the unusual features of the shape of this small satellite, the reaction of the participants in the mission itself speaks for itself. “These pictures are real! Science turned out to be better than fiction,” rejoiced the Cassini mission image processing team.

The tiny satellite, with a diameter of only 32 kilometers, was named after the ancient Greek god of shepherding and cattle breeding for a reason. He belongs to the so-called shepherd satellites. Moving in a circle inside the outer ring A, Pan and similar satellites sweep out the substance of the ring with their attraction, forming a gap around themselves. The Encke division is just such a gap within which Pan rotates. Actually, even before the discovery of Pan, the presence of a gap in the A ring prompted scientists to think about the existence of a satellite in it back in the mid-1980s. However, it itself was not discovered until 1990, when Mark Showalter noticed it while analyzing photographs sent in 1981 by the Voyager 2 robotic station.

In November 2016, Cassini, which has been exploring the Saturn system since 2004, tilted its orbit at the command of scientists and began diving through the planet's rings and exploring their least explored and interesting outer edge. Thanks to its entry into a new orbit with an inclination of 60 degrees from November 30 to April 22, the device began diving through the rings every seven days (20 times in total).

“We call this phase of the mission ring-grazing orbits because we will be able to touch the outer edge of the rings,” explained Linda Spilker, a mission participant at JPL. “In addition, we have two instruments that can sample particles and gases as we cross the plane of the rings, so in some sense Cassini will actually hit the rings.”

This has already made it possible to obtain new photographs of the planet’s rings from unusual angles, and now - to obtain photographs of Pan with unprecedented resolution.

These images were taken from a record close distance of 24,572 kilometers.

The photographs clearly show a ridge that encircles the entire circumference of the unusual satellite and somehow makes it look like either Saturn itself or indeed a flying saucer. A flying saucer, a spaceship, a walnut, ravioli and even a face - this is what people see when they look at the virtually rediscovered satellite of Saturn.

According to scientists, this ridge is the so-called equatorial accretion disk, consisting of material that fell on the surface of the satellite and was part of the surrounding ring. “How different these images are from the barely visible dot I saw in the 1990 Voyager photographs!” “It’s great to finally see Pan this close,” said Showalter, now at the SETI Institute.

It is curious that the oblate shape of Pan was previously known thanks to the first images sent by Cassini at the beginning of its mission. IN article, published in Science back in 2007, scientists suggested that its crest formed long before Pan completely cleaned out the hole in the ring around him.

“Its shape is widely believed to have arisen because the satellite is constantly sweeping fine dust from the ring,” Showalter explained. “Compared to Pan’s size, the rings are very thin, so dust settles on his equator.” According to scientists, Saturn's other moon, Atlas, has a similar shape for the same reason.

Pan– the inner satellite of Saturn near the A ring and Encke: photo, the effect of gravity on the rings, discovery, name and myth, table of parameters, Cassini study.

Pan is the innermost known moon of Saturn and lies within the Encke division of Saturn's A ring. He acts as a "shepherd" companion and is responsible for keeping the Encke division open. The division represents a 325 km (200 mi) passage into Saturn's A ring.

Saturn's moon Pan creates streaks, called "vortices", in the ring material on either side of it. Because the ring particles are closer to Saturn than Pan and move faster in their orbits, these particles pass the moon and receive a gravitational "blow" from Pan. This impact causes waves in the fission as well as throughout the ring, expanding hundreds of kilometers into the rings. These waves intersect into a downward flow, creating vortices - places where the particles of the ring are grouped in an orderly manner due to Pan's gravitational impact.

Pan, like Saturn's moon, has a prominent equatorial ridge that gives the moon a distinctive flying saucer shape.

Discovery of the satellite Pan

Saturn's moon Pan was discovered by M.R. Shoulter in 1990, using images taken by the Voyager 2 spacecraft nine years earlier.

How did the satellite Pan get its name?

Saturn's moons were originally named after the Greco-Roman Titans and their descendants. But as many new moons were discovered, scientists began choosing names from other mythologies, including Gallic, Inuit and Norse stories.

Pan is a satyr (a human-like creature with goat hooves instead of legs) who is the Greek god of nature and the forest.

Thus, you found out which planet Pan is a satellite of.

Admire high-quality, high-resolution photos of Saturn's moon Pan from space.

Photos of the Pan satellite

Cassini managed to obtain this photo on April 3, 2016, at a distance of 373,000 km and at an angle of 140 degrees. Pan and other satellites seriously influence the planetary rings. They form gaps, create arcs, and all this is due to gravity. Pan spans 28 km in width and is located in the center of the frame, namely the Encke Gap. Faint arcs are visible at the bottom right. Many satellites produce waves at distant points in the ring, where particles and moons are in resonance. They differ in color and thickness, and studying them will help to understand the process of formation of a ring system on giant planets. A narrow-angle camera with visible light was used for viewing. Observations were made on the unlit side of the rings at 22 degrees below the plane. Scale – 2 km per pixel. The Cassini program is a joint development of ESA, NASA and the Italian Space Agency. The team is located at the JPL. The two cameras on board were also created by them. The obtained photographs are processed in Boulder (Colorado).

On March 7, 2017, it was possible to obtain two perspectives of Cassini’s passage past Pan at a distance of 24,600 km. This is the closest passage with the ability to detail surface features. Before you are the northern and southern hemispheres. Researchers believe the moon formed in the planet's rings with material accreting onto it. The rounded shape appeared when the outer part of the ring system was younger and vertically denser. As a result, the satellite's icy core is denser than its mantle. It is believed that a thin ridge on the equatorial line formed after the appearance of the satellite and the clearing of the gap between the rings. At the end of the process, the material could have descended onto Pan in this particular area, creating a high ridge. If the body were more massive, then everything would be smoothed out. But gravity is weak, so the particles accumulated. The device was located at a distance of 24,583 km (left) and 37,335 km (right). Scale: 147 m and 224 m per pixel, respectively. The Cassini program is a joint development of ESA, NASA and the Italian Space Agency. The team is located at the JPL. The two cameras on board were also created by them. The extracted images are processed in Boulder, Colorado.