The Search for ExtraTerrestrial Intelligence (SETI) focuses mainly on looking for radio signals from civilizations elsewhere in the galaxy, but the SETI Institute is taking a new approach – and it involves lasers. Seeking funding via a crowdfunding campaign, the Institute wants to build a series of specialized camera observatories to constantly scan the entire sky in search for transient laser flashes that could be signs of intelligent life.
For the past 60 years, the favored strategy for seeking signs of extraterrestrial civilizations has been to look for radio signals being deliberately beamed at the Earth. As such, the conventional SETI strategy is to look for long, repeating signals that are beamed at us for days or even months at a time on the assumption that the sender would want to give us time to notice the signal, then record several repetitions of it as a way to fill in any gaps caused by interference or the source setting below the horizon.
However, that isn't the only possible medium of interstellar communication. Lasers can also, in theory, be used to send messages between the stars. That's because they can be focused into extremely tight beams and tuned into monochromatic frequencies that can penetrate the dust and gas of space. Also, any laser signals reaching us may be very brief because they aren't intentionally aimed at us, but we just happen to be in the way for a short time. The same may be true of radio beams, but lasers are different in that it's possible to look at much larger sections of the sky at once for them than compared to radio signals.
What the SETI Institute plans is to set up a series of observatories around the world using specialized wide-angle cameras that can constantly watch the entire sky for signs of laser flashes that could be of intelligent origin. Called Laser SETI, the project intends to detect flashes as short as a millisecond or less, whether they repeat or not.
The private, nonprofit says that it has been working on the experiment for two years and is now ready to move to the field observation phase, but that means raising funds for the installation of two detectors and their operation. The hope is that this will eventually lead to large-scale production and deployment around the world.
The cameras use wide-angle optics and slitless spectroscopy to seek out monochromatic flashes in the sky at a rate of 1,000 frames per second. Using two cameras acting as back ups for each other, it's possible to cover large areas quickly and at lower cost.
As part of this effort, the Institute is running an Indiegogo campaign through next month with a goal of US$100,000. The money will be used to buy the two cameras and fabricate the specialized optics as well as cover initial operating costs as the equipment and its computer algorithms are tested. The Institute says that the goal is flexible and that additional funds will be used by the project up to US$510,000 for two complete observatories.
The ultimate goal is to one day have 14 observatories spread across the globe for continual observation regardless of weather with redundant observatories providing validation for any signals detected.
Perks for campaign contributors range for a sticker for US$25, to attendance at the launch party when the first observatory goes on line for US$10,000. At the time of publication, the campaign has raised just under a quarter of its goal, with a month left to run.
The video shows the design of the scanning camera.