New computer simulations have suggested the existence of a Mars-sized planet behind Neptune. Credit: NASA

Study Suggests Undiscovered Mars-Sized Planet In Our Solar System

Astronomers around the world have been searching for the so-called "Planet Nine" for several years.


A team of cosmologists presented a new study based on the results of computer simulations of the process of creating the Solar System. In their article, the authors suggest that a planet unknown to us may be located behind Neptune, in fact, a new “Mars-sized planet”.

Computer simulations suggest the existence of a Mars-sized planet behind Neptune

Planet Nine

The idea of a planet behind Neptune itself is not new. Astronomers around the world have been searching for the so-called “Planet Nine” for several years. And the most popular hypothesis is that you should look for it on the outskirts of the solar system. This area is poorly understood: it is rather dark, and the capabilities of modern observation instruments are still limited.


Birth and evolution of the Solar System

However, the new study is interesting because, within its framework, scientists have modeled the process of birth and evolution of the solar system. It did not pursue the goal of finding a hypothetical planet, but it turned out that it actually supported the previously put forward hypothesis. According to the authors of the work, the planet unknown to us could literally be pushed to the “backyard” by gas giants.

Not fully understood

The researchers write that the existing models and the data we have at our disposal do not yet fully explain the current configuration of the solar system. They note that there is something very strange about it.

Arrangement of the planets

The very arrangement of the planets indicates this. As you know, the solar system consists of four rocky planets in the inner part, the asteroid belt, and four gas giants in the outer part.

Something is missing in the configuration

Dwarf planets and other space objects, including comets, move past these giants. Researchers believe that something is missing in this configuration. In their opinion, the system is not balanced, and in general, it is unlikely that in the course of natural evolution in the outer part of the solar system only four gas giants could have formed, and then only dwarfs.


Hypothetical Mars-sized planet pushed away

Scientists suggest that over time, in the course of evolution, such a hypothetical planet could be pushed from its original place further into space. This scenario assumes two options for the further development of events.

Option One

In the first case, the planet could linger on the “outskirts” of the solar system, where it circulates even now in the vicinity of dwarf planets.

Option Two

The second scenario assumes that a hypothetical Mars-sized planet has been pushed into interstellar space and embarked on a long solo journey. The authors of the work hope that the results of the simulation will help future researchers, who will have more powerful and advanced ground-based telescopes at their disposal.

Closer than the Sun than previously thought

By the way, in August 2021, American astronomers Michael E. Brown and Konstantin Batygin presented new calculations that narrow the search for the mysterious “Planet Nine”. The results indicated that its orbit may be much closer to the Sun than previously thought.

Old hypothesis

By the way, in 2016, Brown and Batygin were the first to put forward a hypothesis about the existence of another unknown planet in the solar system.

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Volk, K., & Gladman, B. (n.d.). Transneptunian Space. Annual Reviews.
Whitwam, R. (2021, September 30). A Mars-like planet might be hiding in the outer Solar System. ExtremeTech.
Yirka, B. (2021, October 4). Simulations suggest an Earth or Mars size planet may be lurking out beyond Neptune.

Written by Vladislav Tchakarov

Hello, my name is Vladislav and I am glad to have you here on Curiosmos. As a history student, I have a strong passion for history and science, and the opportunity to research and write in this field on a daily basis is a dream come true.

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