Rings have adorned our fingers for thousands of years, serving as symbols of love and commitment, status, power, wealth and authority. They come in many sizes, shapes and styles, and can be made of metal or other materials. They are often decorated with gemstones. They have myths and legends surrounding them, and are associated with family and social traditions. They are worn by both men and women, but in recent times mainly by women.
In modern mathematics, a ring is a set with two operations: addition and multiplication (which may or not be commutative; and may or may not have an identity and inverses). The canonical commutative ring is the integers; more generally, rings show up in number theory and topology.
The earliest rings were worn as simple ornaments. Later, people began to wear them as symbols of betrothal and marriage. Traditionally, only women wore engagement and wedding rings, but in the last century, men have also begun to do so. Some men also wear rings to signify friendship or membership in a club.
There are many different types of rings, and they can be made of gold, silver, platinum or other precious metals. They can be set with diamonds, sapphires or other gems. They can be plain, or they can have intricate designs. There are also rings that are made of materials such as bone or glass. Some are carved into the shape of animals or flowers, or of human hands. In some cultures, wearing a ring is seen as a good luck charm, while in others it is unlucky.
A ring is usually circular in shape, but it can also be square or rectangular. Its sides can be flat or curved. The central part of the ring is called the bezel, and it may be set with a single stone or with several small stones. There are also a variety of settings, including channel and pave settings, in which rows of tiny stones are set along the ring’s band, and the prong setting, in which thin metal “claws” extend up from the band to hold a larger center stone.
Astronomers have long understood that some planets have rings, but the nature of these structures is still a mystery. Gravitational tugs from a planet’s satellites explain some of the structure of these rings. In addition, there are rings that have no orbiting moons, but are likely composed of debris blown out from the planet’s surface. Other rings may be the result of collisions between icy bodies such as Neptune’s and Pluto’s rings.
In the future, it is expected that more rings will be discovered as spacecraft make close passes of the giant planets in their orbits. Such studies will help astronomers to understand how these rings were formed and why they are arranged as they are. They will also assist in determining whether Neptune’s rings are the remnants of a former planetary moon or the products of collisions between rings and objects from the Kuiper Belt beyond Neptune’s orbit.