WASHINGTON—Scientists have expanded the search for technologically advanced extraterrestrial civilizations by monitoring a star-dense region toward the core of our galaxy for a type of signal that could be produced by potential intelligent aliens that until now has been ignored.
Efforts to detect alien technological signatures previously have focused on a narrowband radio signal type concentrated in a limited frequency range or on single unusual transmissions. The new initiative, scientists said on Wednesday, focuses on a different signal type that perhaps could enable advanced civilizations to communicate across the vast distances of interstellar space.
These wideband pulsating signals for which the scientists are monitoring feature repetitive patterns—a series of pulses repeating every 11 to 100 seconds and spread across a few kilohertz, similar to pulses used in radar transmission. The search involves a frequency range covering a bit less than a tenth the width of an average FM radio station….