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Topic: Planetary ring

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In the News (Fri 16 Aug 19)

  Planetary ring - Wikipedia, the free encyclopedia
The origin of planetary rings is not precisely known, but they are thought to be unstable and dissipate over the course of tens or hundreds of millions of years.
As a result, current ring systems must be of modern origin, possibly formed of debris from a moon that suffered a large impact or was disrupted by the parent planet's gravity when it passed within the Roche limit.
It is possible that these rings are composed of material that is being pulled off of these two bodies by Jupiter's tidal forces, possibly facilitated by impacts of ring material on their surfaces.
en.wikipedia.org /wiki/Planetary_ring   (394 words)

 Ring article - Ring circle noise cycles ring ring theory mathematics ring telephone - What-Means.com   (Site not responding. Last check: 2007-11-06)
A ring is usually anything resembling a circle, or a noise that cycles rapidly.
The Opera cycle Der Ring des Nibelungen (The Ring of the Nibelung) is often referred to as "the Ring"
The Ring is an American remake of Ring.
www.what-means.com /encyclopedia/Ring   (183 words)

 An Integrated Strategy for Planetary Sciences 1995-2010
Planetary rings, which for centuries were thought to be unique attributes of Saturn, have recently been observed around all the giant planets.17 Surprisingly, each ring system is distinctive.
Saturn's rings, which are predominantly composed of water ice particles that are centimeters to meters in size, are broad, bright, and opaque; they exhibit the most diversity in their organization and variety.
All rings lie close to their planet's equatorial plane, and most are within their planet's Roche limit, where tidal forces would tear asunder a self-gravitating fluid body; they also extend out into the planet's magnetosphere and, in the case of Uranus, dip down within the upper reaches of the planetary atmosphere.
www.nap.edu /readingroom/books/planet_sci/contents/chap4c.html   (1699 words)

 Planetary Rings
This in turn suggests that the rings of Saturn are very thin relative to their diameter; in fact, if you were to build a scale model of Saturn, making the rings only as thick as a piece of typing paper, about 0.1 millimeters, the diameter of the ring system would be about forty meters.
The American Pioneer and Voyager spacecraft have revealed the rings of Saturn to be composed of icy particles ranging in size from a fraction of a millimeter to twenty or thirty meters across.
Planetary rings are probably created when a small moon collides with another moon, or ventures so close to its planet that gravitational tidal forces shred it apart.
www.astro-tom.com /getting_started/planetary_rings.htm   (575 words)

 Drive axle outer end with brake and gearing - Patent 4037694
Planetary reduction outer ends are used as the final drive in axles for many heavy duty, off-highway type vehicles which are employed in the construction, logging and mining industries, as well as in farming and for mobile materials handling equipment and heavy industrial machinery.
Ring gear 24 is held axially in place on mounting member 22 between the radial shoulder defined by the end face 65 of the ring gear teeth and a washer 66 held in place on the end of the ring gear 24 by a plurality of bolts 68.
The ring 89 serves as an abutment limiting the extent of axially outward movement of the pressure plate 84, brake discs 81, 82 and pressure plate 85.
www.freepatentsonline.com /4037694.html   (2830 words)

 Planetary ring -- Facts, Info, and Encyclopedia article   (Site not responding. Last check: 2007-11-06)
A planetary ring is a ring of dust and other small particles (The (usually elliptical) path described by one celestial body in its revolution about another) orbiting around a (Any of the celestial bodies (other than comets or satellites) that revolve around the sun in the solar system) planet in a flat disc-shaped region.
As a result, modern ring systems must be of modern origin, possibly formed of debris from a (Any natural satellite of a planet) moon that suffered a large impact or was disrupted by the parent planet's gravity when it passed within the (Click link for more info and facts about Roche limit) Roche limit.
It is possible that these rings are composed of material that is being pulled off of these two bodies by Jupiter's (Click link for more info and facts about tidal force) tidal forces, possibly facilitated by impacts of ring material on their surfaces.
www.absoluteastronomy.com /encyclopedia/p/pl/planetary_ring.htm   (517 words)

 * M57 - (Astronomy): Definition   (Site not responding. Last check: 2007-11-06)
Ring Nebula in Lyra was discovered by Antoine Darquier de Pellepoix in 1779 and Messier observed it on January 31, 1779...
The ring itself should be clearly visible in medium scopes, while the fourteen magnitude central star may take a little longer...
The "Ring Nebula (M57)" in the constellation Lyra, discovered in 1779, is regarded as something of a "prototype" of planetary nebulas.
www.bestknows.com /astronomy/m57.html   (479 words)

 [49.07] Structure and Transport Prosess in a Dense Planetary Ring   (Site not responding. Last check: 2007-11-06)
We have investigated the structure and transport process in a dense planetary ring such as Saturn's main rings by performing local N-body simulations including both self-gravitational interactions and inelastic collisions between ring particles.
We separately calculate the gravitational viscosity due to torque caused by the wake structure, the translational(local) viscosity, and the collisional viscosity.
When the wakes strongly develop, the gravitational viscosity and the translational viscosity due to collective motion of the particles caused by wakes are dominant, whereas the collisional viscosity and the local viscosity due to random motion are less significant in the ring's viscosity.
www.aas.org /publications/baas/v32n3/dps2000/307.htm   (376 words)

Planetary nebulae offer the astronomer the opportunity to view into the workings of stellar evolution once the veil of gases have been lifted by the very process of their formation.
Planetary nebulae result when shells of gases are expelled by a red giant star as it nears the end of its life cycle.
Planetary nebulae have nothing to do with planets; which may form in the earlier stages of a stars existence but not near their ending.
www.howard.k12.md.us /white/PlanetNebulae.html   (915 words)

 Messier Object 57
The famous ring nebula M57 is often regarded as the prototype of a planetary nebula, and a showpiece in the northern hemisphere summer sky.
Recent research has confirmed that it is, most probably, actually a ring (torus) of bright light-emitting material surrounding its central star, and not a spherical (or ellipsoidal) shell, thus coinciding with an early assumption by John Herschel.
As most planetary nebulae, the Ring is much brighter visually at magnitude 8.8 than photographically at only 9.7 mag; a consequence of the fact that most light is emitted in very few particular spectral lines (see the discussion in our planetary nebulae page).
www.seds.org /messier/m/m057.html   (1349 words)

 2MASS Atlas Image Gallery
Planetary nebulae are formed as low-mass stars, like the Sun, reach the end of their lives and lose their outer envelopes to the interstellar medium.
Planetary nebulae are formed as low-mass stars, like our Sun, reach the end of their lives and lose their outer envelopes (for this nebula, what are now the ring and halo structures) to the interstellar medium.
The bright ring is the equatorial torus, from a high-density slow wind from the evolving star, whereas the fainter halo structures are the polar lobes and the remnants of a faster, low-density wind.
www.ipac.caltech.edu /2mass/gallery/images_pne.html   (2017 words)

 Rings of Saturn
Rings C, B and A are the three major rings of the ring system and can be seen from Earth.
The C ring is the faintest of the three and is almost translucent.
The B ring is the brightest of the three followed by the somewhat fainter A ring.
1scom.net /~kjblackford/saturn-rings.html   (710 words)

 TPS: The Alphabet Soup of Saturn's Rings
To the left of the F ring is the A ring, with the Encke Division near the outer edge.
Ring R/2004 S1 The Cassini imaging team announced on September 9, 2004 the discovery of a new ring orbiting in the same position as the moon Atlas, in the gap between the A and F rings.
Because the rings are bright, they must be made of chunks of icy material; because the rings are so thin, the chunks must be small, no more than a couple of meters across at most, and frequent collisions between ring particles would tend to break big chunks into smaller ones.
www.planetary.org /saturn/rings.html   (2200 words)

 COLLIDE Experimental Objectives
Low velocity collisions between planetary ring particles are crucial in determining the dynamics of planetary rings and also determine the characteristics of dust rings which are often the only observable component of a planetary ring.
The dust component of rings is visible in high phase angle viewing geometries achieved by spacecraft, and is often the only component of a ring that is visible.
Targets and impactors in planetary rings or the early proto-planetary nebula that impact at speeds less than meters per seconds are meter-scale or smaller.
lasp.colorado.edu /collide/experiment.html   (3109 words)

 ring, planetary
Ring matter — whether it is dust particles or huge boulders — will orbit a planet without coalescing into a single body if it remains within a certain distance, known as the Roche limit.
The various rings have different proportions of ice and rock, and different distribution of particle sizes.
See rings of Jupiter, rings of Saturn, rings of Uranus, and rings of Neptune.
www.daviddarling.info /encyclopedia/R/ring_planetary.html   (209 words)

 ASTR 1110 Lectures Spring 1999   (Site not responding. Last check: 2007-11-06)
We defined a planetary ring as a collection of many particles on similar orbits around a planet.
That is, the primary method of observation of a planetary ring is through the collective effects of the particles while, for example, a moon is a single particle which can be independently observed.
The intensity of the light source is observed as the ring passes in front of it.
lasp.colorado.edu /~colwell/astr3750-f00/oct10notes.html   (480 words)

 Saturn.Quest.   (Site not responding. Last check: 2007-11-06)
Ring particles are maintained both by the effects of shepherd moons which keep them confined to a particular orbit and are manufactured as larger bodies are ground up within the rings.
Rings can be preserved with by the presence of shepherding moons which confine the ring particle orbits or by the presence of larger bodies in the rings which resupply the rings with small particles as they are ground up.
Planetary rings usually occur inside the Roche limit, defined as the distance at which a liquid moon would be broken up by the tidal forces of the planet.
webs.wichita.edu /astronomy/wqquestions/saturn_q.htm   (1623 words)

 Studies on the Rings of Saturn
For an explanation of the phenomenon of the variable azimuth brightness of Saturn's A ring, hypotheses based on the assumption of synchronous rotation of particles, or with the asymmetrical form as extended ellipsoids, or with asymmetrical albedo of the surface, were put forth.
It must be said that the existence of radial structures in a planetary ring throws a call to all traditional representations.
If the ring is a source of SED, the area of the source can be located at a distance of 107,990-109,200 km from the planet according to measured periodicity[6].
www.affs.org /html/studies_on_the_rings_of_saturn.html   (1496 words)

 Planetary Nebulae
On November 13, 1790, Herschel found the planetary nebula NGC 1514 (his H IV.69), which has a very bright central star; thus he became convinced that the planetary nebulae were nebulous material (gas or dust) associated with a central star, and not unresolved clusters as he and others had thought previously.
The planetary nebula has only a short life compared to the time scales in stellar evolution, being visible only a few thousands or 10,000s of years, and then fading out as its matter is spread in the cosmic environment, enriching the interstellar matter with carbon, oxygene, and other elements.
Planetary nebulae have also been discovered in other galaxies with large telescopes, including the Large and the Small Magellanic Cloud, the Andromeda Galaxy M31, M33, M32, and NGC 6822 as well as other galaxies in the Local Group and beyond.
www.seds.org /messier/planetar.html   (1297 words)

 Tranquility Plane - Side View of Planetary Ring System   (Site not responding. Last check: 2007-11-06)
The planet appears as though it is floating in the vacuum of space and surrounded with a tenuous atmosphere.
Planetary rings consist of a thin collection of solid particles distributed around a planet.
Typical elements are stars, space gas, moons, planets, planetary rings, etc. The environment was constructed with sculpturing, air brushing, and other multi-disciplined techniques then photographed directly on film within the camera using specially developed photographic masking techniques.
home.san.rr.com /port/space/tranqy.html   (317 words)

 Paradoxes Resolved, Origins Illuminated - Planetary RIng Formation
It is my contention that the ring system of a central body is formed within the ``heliospheric current sheet'' of that body.
There is clearly a "pinched area" formed by the two opposing magnetic fields that bound the current sheet, with the pinch growing tighter closer to the main body (Uranus picture) http://www.abc.net.au/science/news/stories/s1241987.htm, and cutting off at the magnetic loop point.
The spacing(lumpiness) in the rings is due to a phasing or resonance between the negative and positive side of the current sheet.
www.metaresearch.org /msgboard/topic.asp?TOPIC_ID=603   (326 words)

 The Nine Planets Glossary
the eccentricity of an ellipse (planetary orbit) is the ratio of the distance between the foci and the major axis.
a planetary orbit) is 1/2 the length of the major axis which is a segment of a line passing thru the foci of the ellipse with endpoints on the ellipse itself.
The semimajor axis of a planetary orbit is also the average distance from the planet to its primary.
www.nineplanets.org /help.html   (4842 words)

 Encyclopedia: Planetary ring
Saturns rings; the major rings are labelled This is a list of the 15 named rings of Saturn, and the gaps between them.
This is a list of the named planetary rings of Uranus.
This is a list of the named rings and ring arcs of Neptune.
www.nationmaster.com /encyclopedia/Planetary-ring   (1067 words)

 PtyS/LPL Faculty: Dr. Carolyn C. Porco
In this area, she established (among other phenomena) the shepherding of the Uranian epsilon and delta rings by the satellites Cordelia and Ophelia, and the confinement of the Neptune ring arcs by the satellite Galatea.
She has investigated the behavior of the Saturn ring spokes, establishing the connection between the variable appearance of the spokes and Saturn's magnetic field.
To guide the ring sequencing, she is continuing her research in the above areas, as well as embarking on a new study of the photometric behavior of Saturn's rings.
www.lpl.arizona.edu /people/faculty/porco.html   (246 words)

 Hubble Heritage
His primary research interests are the formation of planetary systems, planetary dynamics and chaos, planetary ring systems, and circumstellar/protoplanetary disks.
In addition to HST imaging projects, his work on the studies of planetary ring systems has included analysis of the interactions between rings and moons and their implications for the ages of ring systems.
Additionally, he is searching for extrasolar planetary systems, both from the ground and, hopefully, in the future with the proposed Kepler spacecraft.
heritage.stsci.edu /2001/15/bio/bio_lissauer.html   (206 words)

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