The idea of an additional, distant planet has accompanied astronomy for over a hundred years. Early scientists speculated that beyond the known orbit of Neptune another celestial body might exist, whose gravitational influence could be detected on smaller objects in the outer solar system.
This hypothesis gained renewed interest in recent decades when studies revealed unusual orbital behavior among certain trans‑Neptunian objects. The proposed explanation is a massive planet located several hundred astronomical units away, whose gravity could account for the observed anomalies.
Searching for such a body is challenging because it would be extremely faint and detectable only with the most powerful telescopes and extensive sky surveys. Researchers analyze both visible and infrared data to identify minute motions against the backdrop of fixed stars.
To date, no direct observation has confirmed the planet’s existence, yet the question remains an active area of research. Future observatories and expanded datasets may either verify the presence of a distant planet or ultimately rule out the hypothesis.