Rings of Saturn - new discoveries

Saturn's rings are mainly made of water ice - 90%-95%. Since dust and fragments of rocky meteorites contaminated the rings, it is estimated that when they were formed they contained only water ice.

The contents of the rings
Saturn's rings are mainly made of water ice - 90%-95%. Since dust and fragments of rocky meteorites contaminated the rings, it is estimated that when they were formed they contained only water ice. The current composition of the rings differs from the accepted estimate according to which in the outer parts of the solar system, half of the rings' content was water ice and the other half a mixture of rocks originating from the outer parts of the solar system. Similarly, the low densities of the moons near Saturn indicate that these bodies contain an abnormal amount of ice. According to the previous estimate, the origin of the rings is a small moon that collided with a comet. The result, rings that contain a mixture of ice and rock (1). It is important to note that the general picture of the rings will only be made after the Cassini spacecraft completes its mission in 2015.

B ring

Photographs of this ring revealed new details. The description of the findings will be made for each photograph separately,

1. Photo PIA11669 - Cassini division (Cassini division) An area with low density is between ring A and ring B. Along and parallel to the outer edge of the B ring is a configuration similar to a chevron 20,000 km long. Photographs taken during the equinox (the day when the sun is above Saturn's equator) showed that in this place there are structures vertical to the ring and 3.5 km high. It turned out that there are two chevrons on the outer rim of the ring that are not even affected by one of the three rotating patterns around the ring, which distort the rim of the ring or a pattern that was known to be affected by the melting moon. It turned out that one chevron circles Saturn as if it were an independent body. Therefore, the assessment reached by the researchers is that these are moons located near the rim of the ring and surround it independently. The moons in this photograph are large enough to affect the ring material near them, compressing and ejecting it in a direction perpendicular to the plane of the ring. This estimate is supported by the earlier discovery of a 300-meter-long body on the outer rim of the ring (2).

2. Photograph PIA12794 - During a series of photographs that lasted 9 hours, the outer rim of the ring was observed. 301 photographs were taken. It turned out that the outer rim moves in and out in a complex manner and the wavelength of each such oscillation from end to end is 200 km. The conclusion reached by the researchers is that 4 wavy oscillations (scalloped patterns) move independently around the ring. A single pattern with two lobes is formed due to the gravitational effects of the melting moon. This moon causes changes in the orbits of the particles due to the repeating pattern following a change in the orbits of the particles in the ring.

The other patterns one with one lobe and the other with two lobes and the third with three lobes circle the rings at different speeds each. It seems that these are natural modes of oscillations in the ring in this place. These patterns are driven by a process called viscous over stability. In this process, small and intermittent movements of particles transfer energy into the wave moving outward and inward - from the inner rim out to the outer rim - and from there back in. This in-and-out movement allows these patterns to grow and look like the deformation of the outer rim of the ring (4).

C ring

A tsunami-like phenomenon was observed by Cassini in the C ring. Waves of ice particles rising to a height of 1.6 km were seen surrounding the rings. The observed waves were created by the moon Titan whose gravity pulls them upwards C. These waves create high crests and large gaps. Other waves are not formed at all under the influence of any moon. The intervals also appear to grow and disappear cyclically (5).

F ring

In the F ring, dense enough objects were found that were given the name "self gravity". Compared to the moon Prometheus, they can attract more particles and ice balls. A question that arose is how the ice balls in the ring can survive due to their location. The explanation for this is that the ring is at the point of balance between the tidal forces of Saturn and their own gravity. According to another approach, this ring in its current state is probably 1 million years old, but every few million years it is filled by moons coming from the main rings and that the snowballs that form and break up have a lifespan of several months. The findings can also provide an answer regarding the origin of a body with a diameter of 5-10 km that was first observed in 2004 that sometimes penetrates the ring and creates jets of fragments (6).

The impression received by the researchers is that the ring is much more dynamic than previously thought. It contains bodies of various sizes from 0.8 km to moons such as Prometheus, which are 160 km long and can create channels, ripples and snowballs in this ring. Some of the snowballs broke up due to collisions or tidal forces during their movement around Saturn. The smallest of them can exist for a long time. The findings indicate that some of the small bodies survive these collisions and that they change their orbits and move to the entire width of the ring. Small objects hit the rest of the ring at a speed of 6.4 km/h. The collisions throw luminous particles outside the ring and create trails ranging in length from 40-180 km (7).

Blades

For several years we have been monitoring a phenomenon that was discovered in the last few years in the A ring. These are small bodies with formations of blades on both sides and therefore received the name propeller moonlets. One of them was named Sikorsky. Its length is 50 km. Based on tracking his movement, they came to the conclusion where he would be after the observations. In a photo taken on June 5.6.2012, 6, it turned out that it was at a distance of 13,000 ° from the expected (8 km). This gap between the prediction and what was observed is probably due to an interaction between the moons and the rings that form the blades (15.12.2006). In a photograph taken on 110, a moon-blade was identified which was given the name Bleriot. The length of the lunar nucleus is 9 km (XNUMX).

In observations made in 2010, another group of bladed moons was identified in the A ring. The blades observed are hundreds of times larger than the blades observed before. Their length can reach thousands of kilometers and their width several kilometers. The moons that were found throw materials up to a height of 0.5 km above and below the plane of the ring. There seem to be dozens of blades of this type. 11 of them were photographed several times between 2005-2009. The blade that was given the name Bleriot was seen in more than 100 photographs. during these 4 years. The large blades changed their course, although it is not clear what the reasons for this were (10).

Another blade was named Earhast and is 0.8 km long. In the other photos (PIA12790) this monthly is found near the Encke gap in ring A. Its length is about 1 km. Its observed shape, like the other moons, depends on the angle at which it is viewed (11).

The effect of the small moons on the rings

In some of the photographs it is possible to notice the influence of the moons Pan and Dephins on what is happening in the ring languages ​​they are adjacent to. The moon Dephins is 8 km long and is located within the Keeler interval in the A ring. It has an inclined path relative to the plane of the ring and its gravity causes the oscillations of particles in the ring that form the rim of the Keeler gap. This moon also shapes the language for the configuration of waves with two components each. One horizontal (radial) component and a second component outside the plane of the ring. The material in the inner rim of the gap moves faster than the moon itself and the particles of the material move in front of the moon. The waves in the outer rim move slower than the moon, so the particles follow it in its movement (12). The second moon Pan is 28 km long and it moves within the Encke interval in ring A. The gravitational force creates dark wakers on the parts of the ring below it (13).

Near the entrance of the Cassini into orbit around Saturn, a granular appearance was discovered on the outer rim of the A ring, this granular appearance was probably created by the effect of the gravitational clumping of the grains together. In photo PIA12722. It is seen that during the movement of the grains around Saturn they are in a fluctuating restlessness under the influence of the gravitational forces of the small moons Janus and Pimatheus. The gravitational resonance of these moons on the outer rim of the ring cyclically causes the granular particles to stick together. The length of the clumps of particles in this photograph can reach several kilometers. The largest of them is 10 km long. A similar tightening of particles is found on the outer rim of a ring B, where the resonance of the melting moon has a similar effect on the orbit of the particles of this ring (14).

In photo PIA12784 you see dark fans above the nucleus of the F ring. They are found near diagonal channels created by the moon Prometheus. These fans are seen to develop as a series of channels within the particles of ring F. They appear to have a common origin and are spread out from the ring radially in all directions. The impression is that the gravitational fluctuations in the ring material are caused by the influence of a moon or clumps of material. The orbits of the moon or clumps of matter are more or less elliptical compared to the rest of this ring. This body is inside the ring and causes the channels of the fans to cluster together (15). In some of the photographs you can see ice particles in the F ring crystallization into large ice balls. When the moon Prometheus creates many oscillations in the ring. Its gravity hits the material of the ring around it and creates wake channels, which in turn cause the formation of clumps 20 km long.

The speed of Prometheus' movement during its orbit around Saturn is greater than the speed of the particles in the ring. As a result of its high speed, it attracts particles in the same section of the ring once every 68 days. In each such transition some of these particles are attracted by it and some of them survive each such encounter. The latter can grow larger and be stable (6).

Sources

1. "Huge collision may have formed Saturn's rings and inner moons" 13.12.2010
http://www.spacedaily.com/reports/ Huge_ Collision_ May _Have_ Formed _Saturn’s _Rings_ And_ Inner_ moons_999.html

2. PIA11669: Strange things afoot in the B ring
http://photojournal/jpl.nasa.gov/catalog/ PIA11669

3. Lindblad resonance – http://en.wikipedia.org/wiki/ Lindblad-resonance

4. PIA12794: Galactic behavior for the outer B ring:
http://photojournal.jpl.nasa.gov/catalog/ PIA12794

5. "Scientist spot Tsunamis in Saturn's rings" 8.10.2010
http://ednetpower.com/xe/23083

6. "Cassini sees moon building giant snowballs in Saturn ring" 23.7.2010
http://www.spacedaily.com/reports/ Cassini _Sees_ Moon_ Building_ Giant_ Snowballs _ In _Saturn _Ring_999.html

7. "Cassini sees objects blazing trails in Saturn ring" 24.4.2012
http://www.spacedaily.com/reports/ Cassini _Sees_ Object_ Blazing_ Trails_ In _ Saturn _Ring_999.html

8. PIA14198: Hello again
http://photojournal.jpl.nasa.gov/catalog/ PIA14198

9. PIA12789: Tracking propeller
http://photojournal.jpl.nasa.gov/catalog/ PIA12789

10. "Saturn propeller reflects solar system origins" 9.7.2010
http://www.spacedaily.com/reports/ Saturn_ Propeller_ Reflects_ Solar _System _Origins
_999.html

11. PIA12790: Sunlit propeller
http://photojournal.jpl.nasa.gov/catalog/ PIA12790

12. PIA12622: Shadows from the wakes
http://photojournal.jpl.nasa.gov/catalog/ PIA12622

13. PIA14608: Ring moon's effects
http://photojournal.jpl.nasa.gov/catalog/ PIA14608

14. PIA12722: Equinoctial clumps
http://photojournal.jpl.nasa.gov/catalog/ PIA12722

15. PIA12784: Multiple F-ring "fans"
http://photojournal.jpl.nasa.gov/catalog/ PIA12484