Caelum Incognitum — The interactive encyclopedia of ufology
2I/Borisov and 3I/ATLAS
Astronomy, exobiology & SETI
After ʻOumuamua (2017), a second interstellar object, comet 2I/Borisov, was discovered in 2019; a third, 3I/ATLAS, in July 2025. Their study confirms that the Solar System regularly receives natural visitors from other stars.