"Exploring the Potential Number of Planets Hidden in the Kuiper Belt"

A study in The Astrophysical Journal Letters suggests that Mars-sized free-floating planets could exist in the Kuiper Belt, far beyond Pluto, potentially captured by the Sun's gravity. These rogue planets, possibly numbering in the billions or trillions galaxy-wide, could inform us about planetary system formation, habitability, and dynamical interactions with stars. Using computer simulations, the study indicates the possibility of a Mars or Mercury-sized body at a distance of 600 to 3,500 AU from the Sun. The research highlights the importance of understanding the capture process of rogue planets and suggests microlensing as a method for their detection.