天文学家发现第三个进入太阳系的“星际访客”

Core Points - Astronomers have confirmed that the interstellar object 3I/ATLAS has entered the solar system and is expected to pass near Mars later this year before exiting the solar system [1][4] - This is the third interstellar object discovered by humanity, following 1I/2017 U1 'Oumuamua' and 2I/Borisov [5] Group 1: Discovery and Characteristics - The object was first reported by the ATLAS telescope in Chile and has been officially named 3I/ATLAS and C/2025 N1 [1] - Initial estimates suggest that 3I/ATLAS has a diameter of approximately 20 kilometers, but this figure has significant uncertainty due to limited data [3] - The object shows signs of cometary activity, indicating it is losing mass, which is typical for comets as they approach the Sun [3] Group 2: Trajectory and Impact - 3I/ATLAS is traveling at a speed exceeding 60 kilometers per second and is currently about 4.5 astronomical units (AU) from the Sun [4] - It is expected to reach its closest point to the Sun at approximately 1.4 AU around October 30, 2023, and will not pose a threat to Earth, remaining over 240 million kilometers away [4] - The object is anticipated to make a close pass to Mars in early October, with a minimum distance of about 30 million kilometers [4] Group 3: Scientific Significance - The study of interstellar objects like 3I/ATLAS can provide insights into the formation of celestial bodies outside the solar system [5] - Researchers aim to measure various characteristics of these objects to compare them with nearby comets and asteroids, which is crucial for advancing planetary science [5]