It is possible that technologically advanced extraterrestrial civilisations could be using powerful lasers to communicate or to get our attention. And a new tracking system, which is currently being deployed, could be what helps us find traces of such civilisations' activities and attempt to make contact with them.
According to a recent press release from the University of Hawaii, two specialized laser detectors have already been installed in an observatory atop Haleakala Volcano, Maui, Hawaii. These detectors will be paired with similar detectors installed at the Robert Ferguson Observatory in California. And together, these devices will scour the night skies over the Pacific Ocean for laser pulses sent by extraterrestrial civilizations.
Note that the LaserSETI programme, under which this work and research is being conducted, is under the auspices of the SETI Institute, which, as our regular readers are well aware, has been trying unsuccessfully to detect radio signals of extraterrestrial origin for many years. "The search for artificially generated light makes quite a lot of sense due to the fact that data transmission by light has many advantages over transmission by radio waves," the researchers write, "And technologically advanced civilizations are much more likely to use lasers to enable their internal and external communications."
Note that LaserSETI is not the first attempt to detect artificial laser radiation of extraterrestrial origin. However, previous projects have used conventional photomultiplier tubes, which are essentially high-sensitivity cameras with a single-pixel matrix. And such cameras can only cover a small fraction of the available space.
The new system, developed jointly by experts from the Institute SETI and the Institute for Astronomy (Institute for Astronomy, IfA) at the University of Hawaii, will be able to control almost the entire night sky. The basis of this system is the assumption that light from extraterrestrial lasers must be monochromatic, as light from any type of laser should be. This, in turn, allows relatively slow two-dimensional solid-state arrays, like those used in expensive professional video cameras, to be used as detectors.
Each of the detectors is equipped with two cameras, the sensors of which are arranged at an angle of 90 degrees. A special device splits the incoming light into a spectrum, which is recorded by the camera at high speed. The wide-angle input lenses provide a detector lens angle of 75 degrees, so only a few of these detectors are needed to "catch a glimpse" of the entire night sky.
"LaserSETI is the first project in the history of traditional and radio astronomy that will cover the entire night sky," said Eliot Gillum, scientific leader of the project. "Only in this case we will be looking for signs of techno-signs in the light falling in the detector lenses.
The LaserSETI devices installed in Hawaii will be oriented eastward, while those in California will be oriented westward. The observations from these detectors would overlap and would be important to triangulate detected light sources outside the solar system and to exclude local sources such as planes and artificial satellites.
LaserSETI is currently in the deployment phase. In addition to the two detectors already installed, ten more are planned, which will be located in Puerto Rico, the Canary Islands and Chile.