# Modelling the Dynamics of a Hypothetical Planet X by way of Gravitational N-body Simulator

## TL;DR

This paper presents an educational activity using gravitational N-body simulations to model a hypothetical Planet X, demonstrating its unlikely stable orbit and debunking myths about its existence and effects on Earth.

## Contribution

It introduces a simulation-based activity for undergraduates to critically assess the plausibility of a hypothesized Planet X in our Solar System.

## Key findings

- Simulations show Planet X would be detectable if it existed.
- A highly eccentric orbit would be unstable over long timescales.
- The activity effectively debunks myths about Planet X's influence.

## Abstract

This paper describes a novel activity to model the dynamics of a Jupiter-mass, trans-Neptunian planet of a highly eccentric orbit. Despite a history rooted in modern astronomy, "Planet X", a hypothesised hidden planet lurking in our outer Solar System, has often been touted by conspiracy theorists as the cause of past mass extinction events on Earth, as well as other modern-day doomsday scenarios. Frequently dismissed as pseudoscience by astronomers, these stories continue to draw the attention of the public by provoking mass media coverage. Targeted at junior undergraduate levels, this activity allows students to debunk some of the myths surrounding Planet X by using simulation software to demonstrate that such a large-mass planet with extreme eccentricity would be unable to enter our Solar System unnoticed, let alone maintain a stable orbit.