The Oort cloud gets its name from a Dutch astronomer by the name Jan Oort who, in 1950, suggested the idea of the existence of a cloud of icy bodies. Oort also suggested that the cloud was the source of a number of the comets that came into the solar system.
The hypothetical cloud is thought to surround the sun at a distance of between 0.03 and 3.2 light-years away. The cloud is thought to extend to about a third of the distance from the sun to the neighboring star. The Voyager 1 spacecraft from NASA would probably take 300 years to get to the Oort cloud and about 30,000 years to get to the other side of the cloud. The Oort cloud has yet to be fully discovered or seen with current telescopes.
The Oort cloud is thought to contain billions or trillions of bodies of varying sizes (some of them being large enough to be considered dwarf planets). The objects in the Oort cloud are mainly comprised of ice of methane, ammonia, and water. The population of objects in this region is in a constant state of flux with some of the objects being permanently booted out through interactions with passing molecular clouds and stars and some being occasionally captured by the sun from the shells of other stars.
Scientists believe that the Oort cloud was formed nearly 4.6 billion years ago after the formation of planets. One of the most popular theories suggests that the objects that comprise the Oort cloud were initially converged closer to the sun when the planets were formed. Strong gravitational influences from planets such as Jupiter subsequently dispersed the objects into wide elliptical orbits that were then affected by passing molecular clouds and stars which placed them in orbits that are detached from the gas giant region.