A ring is any circular band of gold, silver, or other precious metal or material that is worn as ornamental jewellery. Rings may be used as jewelry, tokens of love, symbols of religious faith or cultural heritage, to mark a special occasion, or to indicate a membership in an organization or social status. They are usually worn on the fingers, but they can also be placed on other parts of the body such as on the nose or on the thumb (see finger ring). A ring must fit snugly around the part of the body it ornaments, and bands worn loosely are not rings.
In mathematics, a ring is a set of numbers that must have the properties of addition and multiplication. This is a generalization of the set of integers, which has to include a zero element, negatives for all elements, and two distributive laws: commutative addition [a + b = ab for all a, b], and associative multiplication [(a) * c = ac for all a, b, and c].
When writing fiction, a writer can use rings to signify many things to their readers. The most common use of rings is to show that a character is engaged or unmarried, but they can also be used to demonstrate wealth, high status, and association. In ancient times, the specific fingers on which a ring was worn portrayed various symbolic associations and meanings as well.
Rings in space also have significant significance for astronomers, and scientists have been puzzled about how they form. In order to understand them, it is important to know how the rings of different planets are arranged and what forces act on them. For example, the tidal pull of a planet’s gravity keeps ring particles—ranging in size from micron-sized dust to objects as big as houses—from coalescing into larger bodies.
The rings of Saturn, in particular, have baffled scientists. The Cassini spacecraft’s 13-year exploration of the planet and its rings revolutionized our understanding of planetary rings, but there are still many mysteries left to be resolved.
There are several different theories of how ring formation works. One is that the rings are made of leftover material from the planet’s birth 4.6 billion years ago. This theory is controversial, and more research is needed to determine how the ring structure actually forms.
Another theory is that the rings are composed of small moons that orbit each other in close proximity, and that their gravitational tugs keep them together. This is called the ‘pinch’ model of ring formation.
The final possibility is that the rings are formed by debris from a meteoroid strike or by a collision between the planet and its moons. This theory is currently being explored by the Voyager spacecraft as it enters the region of the rings where these effects are strongest. The results should help us better understand how planetary rings form and work in the future.