Since ancient times, humanity has observed glowing lights in the sky that at first seemed to have no explanation. Later with the development of science through observation, they were given the name ‘comets’ and in turn theorized how they were formed. Scientists were amazed that such a large number of comets were crossing the sky, so they speculated that there must be a region in the Solar System with material available for their formation that they called the Oort Cloud.
Comets differ from asteroids thanks to their large halo of light, which is formed by a long, glowing tail and their coma that makes them so bright. But they work in a peculiar way, since they do not shine from the beginning of their time, but instead turn on their brightness as they get closer to the Sun. This is because the more heat they receive from the Big Star, the more they vaporize the frozen material they are made of. compounds. But where does this material come from?
The most accepted theory so far is that right at the edge of the Solar System there is a spherical cloud, a mantle that covers the planetary system and that would be formed by icy rocks of which comets are composed. This cloud was called , in honor of its main theoretical founder, Jan Hendrik Oort.
What is the Oort Cloud?
Theoretically, the Oort Cloud is a spherical cloud composed of mostly icy planetesimals that is believed to surround the Solar System at a distance of 100 thousand Astronomical Units from the Sun, which would be the equivalent of 1.5 light years. Technically it is located in the one that is already outside the domains of our host star, since it is far beyond the heliosphere. The latter is considered the limit of the Solar System, outside of it the Sun no longer has a gravitational predominance.
The idea that a cloud of icy infinitesimals exists at the edge of the Solar System was first proposed in 1932 by the Estonian astronomer Ernst Öpik. At the time Öpik said that long-period comets could have originated in an orbital region at the outer edge of the system.
But later, in 1950, Jan Hendrik Oort developed a theory similar to, although independently of, Öpik’s. And although it has not yet been possible to verify that this limit region really exists since there has been no human ship that reaches such distances, it is very feasible that it does exist since it would explain the behavior of comets that wander through space.
Where is the Oort Cloud located?
According to the analyzes of astronomers, the Oort Cloud is mostly composed of Trans-Neptunian Objects, like the Kuiper Belt, they are called this way because they are beyond the orbit of Neptune. They are believed to be mostly icy volatile objects made up of methane, ethane, carbon monoxide, hydrogen cyanide and ammonia.
Estimates place this icy mantle between two thousand and five thousand Astronomical Units from the Sun. However, the outer edge is believed to be between 100 thousand and 200 thousand Astronomical Units from the Sun.
How did the Oort Cloud originate?
NASA research suggests that most of the icy objects that make up the cloud are the product of an exchange of materials between the Sun and its sister stars, as they approached and separated.
Other research proposes that the existence of the Oort Cloud is broadly consistent with the theory that the Solar System emerged from a cluster of approximately 300 to 400 stars that interacted with each other to form the surrounding space as we know it today. Therefore, the cloud is believed to be the product of gravitational interactions and galactic tides millions of years ago that later gave way to the system.
Unfortunately, no human technology yet has the potential to reach this region of space. What is the space probe that is currently furthest from Earth, is about 300 years away from touching the Oort Cloud, so it is impossible for now to verify it in situ.