No credible evidence exists that U.S. authorities covered up extraterrestrial life, in the form of unidentified flying objects, even if some Americans firmly believe in UFOs, a Pentagon report said Friday.The report offered a number of explanations of what has led to more than 40% of Americans thinking that life forms from another galaxy have visited earth.”Investigative efforts determined that most sightings were the result of misidentification of ordinary objects and phenomena,” according to the conclusion of a 63-page report on “unidentified anomalous phenomena (UAP).” “Although many…