Caelum Incognitum — The interactive encyclopedia of ufology
ʻOumuamua
Astronomy, exobiology & SETI
The first interstellar object detected in the Solar System, spotted in October 2017. Elongated and accelerating slightly without a visible comet tail, it prompted hypotheses, including an artificial object put forward by Avi Loeb. Most astronomers favor natural explanations, such as a fragment of hydrogen or nitrogen ice.