Today in 1978, amateur Australian pilot Frederick Valentich mysteriously disappeared over Bass Strait in southern Australia. Just after 7 p.m., Valentich radioed Melbourne air traffic control in a panic, claiming that an unidentified aircraft was following him. Traffic control told him that no other aircraft were in his vicinity. He described erratic movements, and at one point claimed that the other pilot may have been messing with him. When asked to identify the other aircraft, Valentich responded, "It's not an aircraft." His transmission was then cut off after a short series of sharp, metallic-sounding noises. Valentich and his plane were never found. Many theories had…