There are new clues about the ninth planet, and it is expected to be discovered in about ten years?

An artist's impression of the ninth planet

Planet Nine could be discovered in about a decade, if the currently hypothetical planet actually exists, a new study says, according to Space.com. The study also revealed some new features of Planet Nine.

As early as 2016, two planetary scientists from the California Institute of Technology, Konstantin Batygin and Mike Brown, proposed the so-called "ninth planet". According to their estimates, the mass of this planet may be 10 times that of the Earth, and it orbits the sun at an average distance of about 600 astronomical units. (1 astronomical unit ≈ 150 million kilometers, the average distance between the sun and the earth).

But in a detailed and lengthy paper published online in the academic journal Physics Reports, Batygin, Brown and two other researchers argue that Planet Nine may be smaller and closer to the sun.

The observational evidence and computer simulations they obtained show that the upper limit of the mass of the ninth planet will not exceed 10 Earth masses. The latest orbital calculations show that the ninth planet is a planet with a mass about 5 times that of the Earth, an orbital period of about 10,000 years, and an average distance from the sun should be 400-500 astronomical units.

This also means that the ninth planet may be easier to find than scientists previously expected.

Schematic diagram of the orbit of the ninth planet and comparison of the sizes of the major planets

Interference from Planet Nine

In the paper, the researchers also summarized four main pieces of evidence supporting the existence of Planet Nine based on existing observations. These pieces of evidence all take into account the orbital anomalies of the small Kuiper Belt objects.

The Kuiper Belt is far beyond the orbit of Neptune and is mainly composed of icy celestial bodies, some of which are dwarf planets, such as Pluto and Eris, while others are so small that they can only be called asteroids.

The researchers say the best explanation for the anomalies in the orbits of these small objects is the presence of a large, distant interfering object, whose gravity has pulled the little Kuiper Belt objects into their current orbits.

The magnitude of this disturbance effect depends on the mass of the interfering celestial body and its distance from the sun. Therefore, the ninth planet, which is closer to the sun and has a smaller mass than originally thought, is closer to the current observation results.

The structure of the ninth planet once inferred by two astrophysicists from the University of Bern in Switzerland

Finding Planet Nine is not easy

"While this analysis does not directly say whether Planet Nine exists, it does show that our hypothesis is on solid ground," Brown said in a statement.

Batygin believes that this foundation is very reliable. He once said in an interview that the probability of the existence of the ninth planet is more than 90%. Scott Sheppard, a scientist at the Carnegie Institution for Science, another key figure in the search for the ninth planet, is also optimistic. In his opinion, the probability of the existence of the ninth planet is between 80% and 90%.

It sounds a bit far-fetched that a celestial body much larger than the Earth could have been hidden in the solar system for so long without being discovered. However, according to Batygin's research, the ninth planet is actually very far away. You know, the average distance from Pluto to the sun was only 39.5 astronomical units.

Therefore, the ninth planet, which is 400-500 AU from the Sun, is much farther away, which also means it is dim and astronomers need to do more searching to actually discover it.

Reference Information:

https://www.space.com/planet-nine-easier-find-than-thought.html

Compiled by: Youyou

Planning: Zhang Chao, Li Peiyuan, Yang Liu

Reviewed by: Li Xin, Research Librarian of Beijing Planetarium