# Planet Nine hypothesis and astronomical investigation > Live situation record from CLSTR: https://clstr.news/situations/planet-nine-hypothesis-and-astronomical-investigation > Updated: 2026-09-14T18:26:14.000Z. Sources: 4. Developments: 2. Astronomers are investigating the hypothesis of a ninth planet, often referred to as Planet Nine or Planet X, located at the edge of the solar system. The search is motivated by gravitational anomalies observed in the orbits of distant icy bodies within the Kuiper Belt. These trans-Neptunian objects appear to be clustered and tilted, suggesting the influence of a massive hidden force. Calculations suggest the hypothetical planet could possess a mass between five and ten times that of Earth, with an orbital period of 10,000 to 20,000 years. Because the object is estimated to be 20 to 30 times further from the Sun than Neptune, it reflects very little sunlight, making it difficult to detect with traditional optical telescopes. Researchers are increasingly looking toward infrared spectrum data for evidence. Modern research focuses on the trajectories of small, distant bodies that exhibit peculiar characteristics, such as highly inclined orbits and retrograde movements. Proponents of the hypothesis, including Konstantin Batygin and Michael Brown, maintain that current evidence remains compatible with the existence of Planet Nine. Recent studies have reinforced this by analyzing long-period objects whose stability may be linked to a distant planetary presence. ## Timeline ### 2026-09-14: Astronomers investigate potential existence of Planet Nine Astronomers are studying unusual orbital patterns of distant objects in the Solar System to find evidence of a hypothetical ninth planet, a theory supported by recent research from Caltech scientists. 2 sources. https://clstr.news/cluster/astronomers-investigate-potential-existence-of-planet-nine ### 2026-08-21: Planet Nine hypothesis gains attention through gravitational anomalies Astronomers are investigating the existence of Planet Nine, a hypothetical massive planet suggested by gravitational anomalies in the Kuiper Belt observed by Caltech scientists. 2 sources. https://clstr.news/cluster/planet-nine-hypothesis-gains-attention-through-gravitational-anomalies --- Cite as: Planet Nine hypothesis and astronomical investigation. CLSTR, https://clstr.news/situations/planet-nine-hypothesis-and-astronomical-investigation