Olivia Newton-John, the Grease actress, claims to have seen a UFO when she was a teenager. The 60-year-old performer said that she was "intrigued" by unidentified flying objects and believed that most people in Britain shared her obsession. Newton-John's co-star in the 1978 teenage movie was John Travolta, who is now a member of the Church of Scientology which holds that aliens populated the Earth millions of years ago. But the actress's brush with extraterrestrial life was more mundane. She has described how she saw a silver object flying across the sky at "amazing speeds" when she was 15. "I...