What is the Oort Cloud?

The Oort Cloud is a sphere cloud that is assumed to surround the solar system. It is filled with many inactive comets. It is about 50,000 to 100,000 astronomical units away from the sun. A quarter of the distance from the neighboring star. Astronomers generally believe that the Oort cloud is the remnant of the nebula that formed the sun and its planet 5 billion years ago, and surrounds the solar system.

The Oort cloud was proposed. The scientific community has different theories about their formation. But now, astronomers think that the Oort cloud is the remnant material of the nebula that formed the sun and its planet 5 billion years ago and surrounds it.

The Oort cloud occupies a very large space. It is closest to the sun at 2,000 to 5,000 astronomical units (0.03 to 0.08 light years), and the farthest is 50,000 astronomical units (0.79 light years). The furthest distance is estimated in some literature to be 100,000 to 200,000 astronomical units (1.58 to 3.16 light years). The Oort cloud can be divided into: a spherical outer cloud with a radius of 20,000 to 50,000 astronomical units (0.32 to 0.79 light years), and an annular inner layer with a radius of 2,000 to 20,000 astronomical units (0.03 to 0.32 light years). Clouds. The outer layer is weakly restrained by the interior of the solar system, and long-period comets (possibly also Halley-like comets) are entering

No human-made space probe has reached the Oort Cloud. Among the detectors leaving the solar system, even the fastest and farthest Voyager 1 will reach the Oort Cloud 300 years later, and it will take 30,000 years to cross it. In addition, the radioisotope thermomotor carried by Voyager 1 will no longer be able to provide enough power for scientific instruments around 2025, so it cannot be used for any substantial exploration of the Oort cloud. The remaining four detectors leaving the solar system (Voyager 2, Pioneer 10, Pioneer 11 and New Horizons) will not be operational when they reach the Oort Cloud.