SETI scientists spend most in their time on the lookout for themselves. That is, we have a tendency to search for the categories of radio or light signals that we generate in the world. For example, when Frank Drake began the primary SETI observations in 1960, he chose to appear for signals very similar to those for AM radio broadcasting. It appeared to make sense that if humans use AM radio to communicate, then ET might do the similar. But there’s a vast menagerie of how to encode sound right into a radio signal, for example, using pulses. Drake didn’t search for short pulses. If he had he might need discovered one of those neutron star called a pulsar (figure 1), discovered in 1967 by Jocelyn Bell and earning a Nobel Prize for her postdoctoral advisor, Anthony Hewish.
Drake may well be forgiven for not discovering pulsars. While the electronics in Drakes and Bells telescopes were similar, the designs in their telescopes were vastly different from each other. With a purpose to be superb at discovering carrier-wave like signals, Drakes telescope sacrificed sensitivity to rapidly variable sources. The other was true for Bells telescope. Neither one in every of Drakes nor Bells telescopes will have replaced the opposite. In science, specialization will likely be the important thing to success.
You may think that when the primary 70 years of radio astronomy we might have noticed the entire forms of radio signals that nature has to provide. But you’d be wrong. In 2008 Duncan Lorimer and coworkers discovered an absolutely new roughly radio signal we now call the fast radio burst or FRB. Ironically, FRBs are some of the brightest astronomical radio sources within the universe and detectable bursts appear hundreds of times every day.
Why did it take goodbye for somebody to find FRBs? Because nobody had guessed that enormously bright singleton radio pulses that last just a millisecond were even possible in nature. Hence, no person had designed a telescope able to detecting them until the twenty-first century. Their discovery required a radio telescope with the perfect response time (milliseconds) and exploration of an excessively large fraction of the sky.
Switching gears now to optical SETI, before searches has been designed to seek out either continuous laser signals lasting hours at a time, or extremely short laser pulses lasting just one billionth of a second (one nanosecond). These searches have an easy motivation; for the reason that strongest lasers on this planet operate either continuously or by generating nanosecond pulses, we suppose that ET will communicate with those kinds of signals. But isnt this anthropocentrism? These searches are good so far as they go, but they’re ignorant of pulse durations lasting one millionth or 1000th of a second.
At the SETI Institute, we’re mindful of anthropocentrism. We believe within the necessity of exploring a wide variety of electromagnetic signal types, and particularly, all possible light pulse durations. And customarily speaking, most optical telescopes examine just a tiny fraction of the sky at a time. Even the so-called wide field of view optical telescopes utilized in the Sloan Digital Sky Survey or the massive Synoptic Survey can probe only about 1 part in 5,000 of the sky at any given time.
That is where Laser SETI is available in. Laser SETI will observe the entire sky, the entire time so even relatively rare events are available. Laser SETI can discover pulses over a variety of pulse durations, and is particularly sensitive to millisecond singleton pulses which can was overlooked in previous astronomical surveys. There are good reasons to assume that ET might produce millisecond laser pulses (hint: light-sail spaceships). But equally exciting is the truth that by exploring new territory our probabilities of finding something completely unexpected aren’t zero.
It is tricky to explain the extent of pleasure we feel about this search. We can be probing nature in a brand new way, looking where nobody has looked before. Who knows what we may find? We’d find evidence for an extraterrestrial civilization, and that is our best hope. We also might find some roughly unexpected natural optical signal revealing new physics. Within the latter case, well just must console ourselves with a Nobel Prize.
We invite you to become part of this scientific endeavor. Preliminary designs and proofs of principle are complete. Once we meet our fundraising goal of $100,000, we will install the primary of several optical telescopes world wide and start searching on this new way. We are hoping you’ll join us.