The True Story of a 1967 “Contact” Incident
At the time, the dawn of radio astronomy, the discovery of a source of regular pulses in space was a huge surprise. “We had to face the possibility that the signals were, indeed, generated on a planet circling some distant star, and that they were artificial,” said Hewish later. The timeline behind the discovery stretches over 6 months or so. In August 1967, Bell noticed regular signals at the same sidereal time each day. Almost immediately, the team considered the possibility that the signals were generated by Little Green Men or LGM as they called it.
http://www.technologyreview.com/view/511136/the-true-story-of-a–1967-contact-incident/