UFOs are objects observed in the sky that are not readily identified, with most later being identified as conventional objects like planes or natural phenomena. The term is widely used for claimed observations of interplanetary spacecraft. The document provides two examples of reported UFO sightings from Iran in 2014 and Ireland in 2018 and defines ufology as the study of UFO reports, evidence, and phenomena. It concludes with a brief mention of skulls found with different structures than normal human skulls in relation to the Quran and science.