Seti to build ‘unprecedented’ network to detect lasers from alien civilisations

The Seti Institute, which dedicates itself to the search for extra-terrestrial life, is building an “unprecedented” new network to find aliens.

The LaserSETI network will be able to monitor the entire night sky for lasers that might be used be advanced alien civilisations to communicate. Messages using light are more effective than radio waves because they can convey much more information.

Over the past few decades, there have only been a small number of optical Seti projects which could scan the stars for extremely brief flashes of light – shorter than a second.

“The instruments used for these projects have all relied on photomultiplier tubes to detect the flashes, making them essentially one-pixel cameras”, Seti describes.

The flashes of light, the institute goes on to say, could be homochromatic – and intrinsic characteristic of lasers – and so it could be possible to use relatively slow, two-dimensional solid-state detectors as a part of the search.

The Seti device constructed would use commercial lenses to image 75 degrees of the sky. Behind the lens is a grating that transforms any light source in the camera’s field-of-view into a double rainbow-like spectrum.

While stars will produce a complete spectrum from blue to red, a laser will only show up at its characteristic wavelength.

Each device will consist of two identical cameras, rotated 90 degrees to one another along the viewing axis which – along with the double rainbow response – helps eliminate false alarms that could be caused by cosmic rays. It is also able to distinguish different colours of light, which means it is not limited to detecting short flashes.

“The plan is to build out the discovery network, run it, and then determine what capabilities the next generation of cameras should have,” Eliot Gillum, the institute’s director of optical said.

“What should we build for the ultimate network that will cover both hemispheres? Do we want more spectral or spatial resolution? Perhaps more sensitivity?”

Ten more instruments are under construction for deployment in Puerto Rico, the Canary Islands, and Chile.

The budget for this “discovery” deployment phase is $540,000, of which approximately half has been donated so far. An installation that would cover the whole night sky would cost $5 million.