The Oort Cloud is a hypothetical belt around the solar system filled with asteroids and comets. To date, not a single telescope is capable of detecting such small objects at a considerable distance, however, a lot of indirect evidence indicates that such a formation exists at the far borders of our stellar system. However, the Kuiper belt and the Oort cloud should not be confused. The first also looks like an asteroid belt and includes many
small subjects. It was discovered relatively recently, in the 2000s, when it was discovered that
celestial bodies revolve around the Sun beyond the orbit of Pluto
, some of which are even larger than the ninth planet, but far from all of them had a clear and cleared orbit, constantly shifting in their trajectories under the action of each other. There was a dilemma: on the one hand, they could hardly be called planets, but on the other hand, they are larger than Pluto in size. Then, for the first time in history, modern scientists created a clear list of criteria that a celestial body must meet in order to carry the status of a planet. As a result, Pluto lost this status. In recent years, scientists have discovered dozens of objects in the Kuiper belt. The largest of them are Eris and Sedna.
But what is an Oort cloud?
If the Kuiper belt objects are quite accessible to modern telescopes, then the bodies of this cloud are separated from the Sun by a whole light year. It is still quite difficult to examine them directly at telescopes at such a distance. At the same time, astrophysicists have already discovered dozens of planets even in other stellar systems, but, firstly, they are almost all giant planets like Jupiter, and secondly, they are not observed by themselves, but due to the gravitational influence on their star. However, the Oort cloud literally sends us a lot of evidence of its existence. We are talking about comets that come to the solar system with constant frequency, being messengers of this sphere. Perhaps the most famous example would be Halley's comet. The Oort cloud was named after the Dutch astrophysicist, who in the middle of the 20th century predicted its discovery, based on the observation of long-period comets. This sphere, as well as the Kuiper belt, consists of trans-Neptune objects, which, in turn, consist mainly of ice, as well as methane, carbon monoxide, hydrogen cyanide, ethane and other substances. It is very likely that stone objects can rotate there.
Origin of the sphere
Modern astrophysicists believe that the Kuiper belt, the Oort cloud, is what remains of the substances that formed the solar system, but did not form part of any planet. About five billion years ago, most of the material of an exploding first-generation star (that is, formed relatively soon after the Big Bang) due to gravity and millions of years of compaction transformed into a new star - the Sun. A small part of this protoplanetary spinning disk gathered in huge blocks and formed the planets of our system. The remaining dust and small objects of the nebula were thrown to the very edge of the solar system, forming the Kuiper belt and the very far sphere of the Oort cloud.