Share this Article on Facebook Twitter Submit this article to Reddit Give this article a thumbs-up on StumbleUpon

ring

ring

The Columbia Encyclopedia, 6th ed. | 2011 | Copyright

ring in astronomy, relatively thin band of rocks and dust and ice particles that orbit around a planet in the planet's equatorial plane. All four of the giant planets in the solar system— Jupiter , Saturn , Uranus , and Neptune — have rings, although only those of Saturn are easily visible. The origin of the rings is unknown. One theory is that they may have been formed from moons that were shattered by the impact of comets and meteoroids. Another holds that they might be the remnants of moons or comets that came within the planet's Roche limit and were broken up by gravitational forces. In the case of the E ring, it is now known that geyserlike eruptions on Enceladus are a source of the material in the ring.

Saturn has seven rings designated alphabetically as A through G in the order of their discovery. Two additional rings, designated as R/2004 S1 and R/2004 S2 were discovered in images returned to earth from the Cassini space probe in 2004. In 2009 the Spitzer Space Telescope discovered an enormous but faint dust ring that originates in material removed from the moon Phoebe by impacts. From the planet outward, the rings are D, C, B, A, R/2004 S1, R/2004 S2, F, G, E, and the Phoebe ring. With named gaps occupying the space between several of the rings, Saturn's rings are a highly complex structure stretching almost 167,770 mi (270,000 km) from the planet's center to the farthest edge of ring E; the Phoebe ring extends from 3.7 to 7.4 million mi (6 to 12 million km). The rings are not perfectly circular, and the gaps are not completely empty. The Columbo and Maxwell Gaps separate the C and B rings, the Cassini Division and Huygens Gap separate the B and A rings, and the Encke Division and Keeler Gap separate the A and R/2004 S1 rings. Except for the A and B rings, which are separated primarily by the 2,920-mi-wide (4,700-km) Cassini Division, and the Phoebe ring, the rings are relatively close to one another. Most of the rings appear to be composed of small pieces of water ice mixed with a small amount of rocky material in a wide range of particle sizes, from 1 in. (2.5 cm) to 33 ft (10 m)—although there may be an occasional object as large as a mile (1.6 km) in diameter. The Phoebe ring is composed of dust particles about 10 microns in size. Data returned by Cassini indicates that the rings are not uniform; for example, the B ring is very different from the A and C rings (which are similar to one another) found on either side of it. The Phoebe ring is tilted at a 27° angle from the plane of the other rings and, unlike the other rings, orbits Saturn with a retrograde motion. Several of Saturn's small moons appear to be shepherd satellites, maintaining the shape of the rings through gravitational interactions, and there are also ring arcs associated with several moons.

Jupiter's rings are similar to those of Saturn but much smaller and fainter. The main ring is about 4,300 mi (7,000 km) wide and has an abrupt outer boundary 80,000 mi (128,940 km) from the center of the planet. The inner main ring is formed from dust and ice particles kicked up when meteoroids collide with the small Jovian satellites Metus and Adrastea. The particles then spiral slowly in toward Jupiter. At its inner edge the main ring merges into the halo. A broad, faint band of dust and particles, the halo is about 6,200 mi (10,000 km) thick and stretches halfway from the main ring down to the top of Jupiter's atmosphere. A pair of broad, faint gossamer rings are located just outside the main ring, one bounded by the orbit of the Jovian shepherd satellite Amalthea and the other by the orbit Thebe.

Uranus has a thin elliptical band of eleven faint, narrow rings composed of ice, rock, and dust. Stretching outward from the planet, the rings are named 1986 U2R, Six, Five, Four, Alpha, Beta, Eta, Gamma, Delta, 1986 U1R, and Epsilon; the distance from the planetary center to the Epsilon ring is 31,750 mi (51,140 km). The rings are distinctly different from those of Jupiter and Saturn. A tenuous distribution of fine dust is scattered throughout the ring system, and the rings all are the same flat, dark color (perhaps from methane or black-carbon ice coating the rock), unlike Saturn's bright rings. The nine main rings consist of a single layer of particles, the monolayer, which had not previously been seen in planetary rings; the particles are kept from drifting away by several shepherd satellites. Because there are ringlets and incomplete rings and a varying opacity in several rings, it is believed that the Uranian ring system may be the remnants of a small moon.

Neptune has four almost circular faint rings composed of small rocks and dust. The rings are not uniform in density and thickness; the thicker parts of the rings are called ring arcs. Stretching outward from the planet, the rings are named Galle, Leverrier (whose outer extension is called Lassel), Arago, and Adams (which includes the ring arcs Liberty, Equality, and Fraternity); the distance from the planetary center to the Adams ring is 39,000 mi (62,930 km). The forces responsible for the development of ring arcs and ring extensions are not well understood, but shepherd satellites and gravitational forces attributable to Neptune's moons are thought to play a significant role. Earth-based observations indicate that the rings are less stable than was originally believed.

Show all research tools

Cite this article
Pick a style below, and copy the text for your bibliography.

  • MLA
  • Chicago
  • APA

"ring." The Columbia Encyclopedia, 6th ed.. 2011. Encyclopedia.com. 27 May. 2012 <http://www.encyclopedia.com>.

"ring." The Columbia Encyclopedia, 6th ed.. 2011. Encyclopedia.com. (May 27, 2012). http://www.encyclopedia.com/doc/1E1-ring-astro.html

"ring." The Columbia Encyclopedia, 6th ed.. 2011. Retrieved May 27, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1E1-ring-astro.html

Learn more about citation styles

ring

A Dictionary of Computing | 2004 | | Copyright

ring
1. An algebraic structure R on which there are defined two dyadic operations, normally denoted by + (addition) and · or juxtaposition (multiplication). With respect to addition, R is an abelian group, 〈R, +〉 i.e. + is commutative and associative. With respect to multiplication, R is a semigroup,〈R, ·〉 i.e. · is associative. Further, multiplication is distributive over addition.

Certain kinds of rings are of particular interest:(a)if multiplication is commutative the ring is called a commutative ring;(b)if 〈R, ·〉 is a monoid, the ring is called a ring with an identity;(c)a commutative ring with an identity, and having no nonzero elements x and y with the property that x · y = 0, is said to be an integral domain;(d)a commutative ring with more than one element, and in which every nonzero element has an inverse with respect to multiplication, is called a field.The different identity elements and inverses, when these exist, can be distinguished by talking in terms of additive identities (or zeros), multiplicative identities (or ones), additive inverses, and multiplicative inverses.

The concept of a ring provides an algebraic structure into which can be fitted such diverse items as the integers, polynomials with integer coefficients, and matrices; on all these items it is customary to define two dyadic operations.

2. Another name for circular list, but more generally applied to any list structure where all sublists as well as the list itself are circularly linked.

3. In network topology, a ring network is a closed-loop network that does not require terminators. A token ring topology is physically cabled as a star, with a logical ring maintained at the hub. When a workstation connects to the hub, the ring is extended out to the workstation and back to the hub.
Show all research tools

Cite this article
Pick a style below, and copy the text for your bibliography.

  • MLA
  • Chicago
  • APA

JOHN DAINTITH. "ring." A Dictionary of Computing. 2004. Encyclopedia.com. 27 May. 2012 <http://www.encyclopedia.com>.

JOHN DAINTITH. "ring." A Dictionary of Computing. 2004. Encyclopedia.com. (May 27, 2012). http://www.encyclopedia.com/doc/1O11-ring.html

JOHN DAINTITH. "ring." A Dictionary of Computing. 2004. Retrieved May 27, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O11-ring.html

Learn more about citation styles

ring

The Concise Oxford Dictionary of English Etymology | 1996 | | Copyright

ring1 circle or circlet of metal, etc.; circular group OE.; various transf. and fig. uses esp. from XIV. OE. hring = OS., OHG. hring (Du., G. ring), ON. hringr :— Gmc. *χreŋgaz.
Hence vb. put a ring or circle around; from XV, with corr. formations in the cogn. langs.; cf. OE. be-, ymbhringan surround. Comps. ringdove wood-pigeon. XVI. prob. after LG. or Du. ringfinger third finger. OE. hringfinger. ringleader XVI. f. phr. lead the r. ringlet XVI. ringworm skin disease marked by circular patches. XV.
Show all research tools

Cite this article
Pick a style below, and copy the text for your bibliography.

  • MLA
  • Chicago
  • APA

T. F. HOAD. "ring." The Concise Oxford Dictionary of English Etymology. 1996. Encyclopedia.com. 27 May. 2012 <http://www.encyclopedia.com>.

T. F. HOAD. "ring." The Concise Oxford Dictionary of English Etymology. 1996. Encyclopedia.com. (May 27, 2012). http://www.encyclopedia.com/doc/1O27-ring.html

T. F. HOAD. "ring." The Concise Oxford Dictionary of English Etymology. 1996. Retrieved May 27, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O27-ring.html

Learn more about citation styles

ring

The Columbia Encyclopedia, 6th ed. | 2011 | Copyright

ring in mathematics, system consisting of a set R of elements and two binary operations, such that addition makes R a commutative group and multiplication is associative and distributes over addition (see commutative law ; associative law ; distributive law ). A commutative ring is one in which the commutative law also holds for multiplication. Examples of commutative rings are the sets of integers (see number ) and real numbers. Square matrices (see matrix ) furnish examples of non-communtative rings.

Show all research tools

Cite this article
Pick a style below, and copy the text for your bibliography.

  • MLA
  • Chicago
  • APA

"ring." The Columbia Encyclopedia, 6th ed.. 2011. Encyclopedia.com. 27 May. 2012 <http://www.encyclopedia.com>.

"ring." The Columbia Encyclopedia, 6th ed.. 2011. Encyclopedia.com. (May 27, 2012). http://www.encyclopedia.com/doc/1E1-ring2.html

"ring." The Columbia Encyclopedia, 6th ed.. 2011. Retrieved May 27, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1E1-ring2.html

Learn more about citation styles

Ring

Dictionary of Collective Nouns and Group Terms | 1985 | Copyright

Ring

a circular arrangement or group. See also circle.

Examples : ring of disciples, 1732; of branching elms, 1784; of forts; of all iniquity, 1578; of jewellers—Lipton, 1970; of fair ladies, 1450; of mushrooms; of oaks, 1820.
Show all research tools

Cite this article
Pick a style below, and copy the text for your bibliography.

  • MLA
  • Chicago
  • APA

"Ring." Dictionary of Collective Nouns and Group Terms. 1985. Encyclopedia.com. 27 May. 2012 <http://www.encyclopedia.com>.

"Ring." Dictionary of Collective Nouns and Group Terms. 1985. Encyclopedia.com. (May 27, 2012). http://www.encyclopedia.com/doc/1G2-2505301265.html

"Ring." Dictionary of Collective Nouns and Group Terms. 1985. Retrieved May 27, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1G2-2505301265.html

Learn more about citation styles

ring

The Concise Oxford Dictionary of English Etymology | 1996 | | Copyright

ring2 pt. rang (rung) pp. rung give out a resonant sound OE.; cause (a bell) to do this XII. OE. hringan, corr. to ON. hringja; orig. wk. (OE. pt. hringde, early ME. ringde), but strong forms appear in early XIII.
Show all research tools

Cite this article
Pick a style below, and copy the text for your bibliography.

  • MLA
  • Chicago
  • APA

T. F. HOAD. "ring." The Concise Oxford Dictionary of English Etymology. 1996. Encyclopedia.com. 27 May. 2012 <http://www.encyclopedia.com>.

T. F. HOAD. "ring." The Concise Oxford Dictionary of English Etymology. 1996. Encyclopedia.com. (May 27, 2012). http://www.encyclopedia.com/doc/1O27-ring1.html

T. F. HOAD. "ring." The Concise Oxford Dictionary of English Etymology. 1996. Retrieved May 27, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O27-ring1.html

Learn more about citation styles

ringing

A Dictionary of Computing | 2004 | | Copyright

ringing A damped oscillation that occurs in many electrical circuits when signals change rapidly, and is due often to unwanted capacitance and inductance in devices and connecting wires.
Show all research tools

Cite this article
Pick a style below, and copy the text for your bibliography.

  • MLA
  • Chicago
  • APA

JOHN DAINTITH. "ringing." A Dictionary of Computing. 2004. Encyclopedia.com. 27 May. 2012 <http://www.encyclopedia.com>.

JOHN DAINTITH. "ringing." A Dictionary of Computing. 2004. Encyclopedia.com. (May 27, 2012). http://www.encyclopedia.com/doc/1O11-ringing.html

JOHN DAINTITH. "ringing." A Dictionary of Computing. 2004. Retrieved May 27, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O11-ringing.html

Learn more about citation styles

Ring

A Dictionary of British Place-Names | 2003 | | Copyright

Ring (Rinn) Waterford. ‘Point’.
Show all research tools

Cite this article
Pick a style below, and copy the text for your bibliography.

  • MLA
  • Chicago
  • APA

A. D. MILLS. "Ring." A Dictionary of British Place-Names. 2003. Encyclopedia.com. 27 May. 2012 <http://www.encyclopedia.com>.

A. D. MILLS. "Ring." A Dictionary of British Place-Names. 2003. Encyclopedia.com. (May 27, 2012). http://www.encyclopedia.com/doc/1O40-Ring.html

A. D. MILLS. "Ring." A Dictionary of British Place-Names. 2003. Retrieved May 27, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O40-Ring.html

Learn more about citation styles

ring

A Dictionary of Nursing | 2008 | Copyright

ring (ring) n. (in anatomy) see annulus.
Show all research tools

Cite this article
Pick a style below, and copy the text for your bibliography.

  • MLA
  • Chicago
  • APA

"ring." A Dictionary of Nursing. 2008. Encyclopedia.com. 27 May. 2012 <http://www.encyclopedia.com>.

"ring." A Dictionary of Nursing. 2008. Encyclopedia.com. (May 27, 2012). http://www.encyclopedia.com/doc/1O62-ring.html

"ring." A Dictionary of Nursing. 2008. Retrieved May 27, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O62-ring.html

Learn more about citation styles

ringing

A Dictionary of Earth Sciences | 1999 | | Copyright

ringing See REVERBERATION.
Show all research tools

Cite this article
Pick a style below, and copy the text for your bibliography.

  • MLA
  • Chicago
  • APA

AILSA ALLABY and MICHAEL ALLABY. "ringing." A Dictionary of Earth Sciences. 1999. Encyclopedia.com. 27 May. 2012 <http://www.encyclopedia.com>.

AILSA ALLABY and MICHAEL ALLABY. "ringing." A Dictionary of Earth Sciences. 1999. Encyclopedia.com. (May 27, 2012). http://www.encyclopedia.com/doc/1O13-ringing.html

AILSA ALLABY and MICHAEL ALLABY. "ringing." A Dictionary of Earth Sciences. 1999. Retrieved May 27, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O13-ringing.html

Learn more about citation styles

ring

Oxford Dictionary of Rhymes | 2007 | Copyright

ring •Beijing, bing, bring, Chungking, cling, ding, dingaling, fling, I Ching, king, Kunming, ling, Ming, Nanjing, Peking, ping, ring, sing, Singh, sling, spring, sting, string, swing, Synge, thing, ting, wing, wring, Xining, zing •saying, slaying •bricklaying • minelaying •being, far-seeing, unseeing •sightseeing • well-being •blackberrying •dairying, unvarying •unwearying •self-pitying, unpitying •belying, dying, lying, self-denying, tying, vying •unedifying • unsatisfying • outlying •drawing • underdrawing •easygoing, flowing, going, knowing, mowing, outgoing, showing, sowing, thoroughgoing, toing and froing •seagoing • ongoing • foregoing •theatregoing • churchgoing •following • borrowing • annoying •bluing, doing, misdoing •evil-doing • wrongdoing

Show all research tools

Cite this article
Pick a style below, and copy the text for your bibliography.

  • MLA
  • Chicago
  • APA

"ring." Oxford Dictionary of Rhymes. 2007. Encyclopedia.com. 27 May. 2012 <http://www.encyclopedia.com>.

"ring." Oxford Dictionary of Rhymes. 2007. Encyclopedia.com. (May 27, 2012). http://www.encyclopedia.com/doc/1O233-ring.html

"ring." Oxford Dictionary of Rhymes. 2007. Retrieved May 27, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O233-ring.html

Learn more about citation styles

Free newspaper and magazine articles

RINGS OF GLORY.(General News)(Former UO football players are among the few...
Newspaper article from: The Register Guard (Eugene, OR); 2/6/2005
Piston rings.(SHOP TALK)
Magazine article from: Outdoor Power Equipment; 7/1/2005
On Smarandache rings.(Report)
Magazine article from: Scientia Magna; 12/1/2009

Facts and information from other sites

ring images
ring. (Image by Flickr user Robyn Gallagher, CC)

Related topics

  Be the first to connect related topics with this page!