开年重磅，北大团队证实一颗“流浪”行星！

Core Viewpoint - The research team led by Professor Dong Subo from Peking University has successfully measured the mass of a candidate free-floating planet, confirming its planetary status and that it has a mass comparable to Saturn. This significant finding was published in the journal Science on January 1, 2026, marking a new milestone in the study of rogue planets [1][10][17]. Group 1: Definition and Characteristics of Rogue Planets - Rogue planets are celestial bodies that do not orbit any star and drift through interstellar space, unlike the orderly planets in our solar system [4]. - They may form through two primary mechanisms: being ejected from their original planetary systems due to gravitational interactions or forming directly from interstellar gas clouds that collapse without becoming stars [5]. Group 2: Methodology and Observations - The breakthrough occurred on May 3, 2024, when two ground-based microlensing surveys detected a lensing event lasting about two days, coinciding with the European Space Agency's Gaia satellite observations [6][9]. - The combined observations allowed the research team to utilize a triangulation method to determine the distance and mass of the rogue planet candidate, which was found to be approximately one-fifth the mass of Jupiter and comparable to Saturn [10][9]. Group 3: Implications and Future Research - This research provides strong evidence that the Milky Way may contain billions to trillions of rogue planets, suggesting they are common in the galaxy [10][11]. - The findings pave the way for future large-scale surveys using next-generation telescopes, such as NASA's Nancy Grace Roman Space Telescope and China's upcoming CSST, which aim to discover hundreds of rogue planets [11][10]. - Understanding the origins of these rogue planets could reshape our knowledge of planetary formation and the dynamics of planetary systems [11][10].