外星系不明物体造访太阳系

Core Viewpoint - An unidentified object, possibly an interstellar visitor, has been detected in the solar system, designated as A11pI3Z, which may be the third known interstellar object to visit the solar system [2][3]. Summary by Sections Discovery and Characteristics - The European Space Agency reported that A11pI3Z is located between the asteroid belt and Jupiter, several hundred million kilometers from Earth, and poses no collision threat to Earth [2]. - Researchers are uncertain whether A11pI3Z is a rocky asteroid or a comet composed of rock, ice, and dust, and its shape and size remain unknown [2]. - The object is estimated to be about 40 kilometers wide according to Spanish astrophysicist Josép Trigo Rodríguez, while Harvard astrophysicist Avi Loeb suggests it could be around 19 kilometers wide, which is considered large for interstellar objects [2]. Comparison with Other Interstellar Visitors - The first known interstellar visitor, 'Oumuamua', discovered in October 2017, is approximately 400 meters long, and if A11pI3Z is confirmed to be 19 kilometers wide, it would have a mass 10 million times greater than 'Oumuamua' [3]. - The second known interstellar visitor, 21/Borisov, discovered in 2019, is identified as a comet [3].