Construction is set to begin for a large telescopic array dedicated to detecting natural and artificial sources of optical and infrared light. Once operational, the system, called PANOSETI, will be capable of scanning the entire sky, significantly boosting our chances of detecting alien laser signals.
In development since 2018, PANOSETI, which stands for Pulsed All-sky Near-infrared Optical SETI (Search for Extraterrestrial Intelligence), currently consists of two prototype telescopes stationed at Lick Observatory near San Jose, California, according to a UC San Diego press release. These telescopes have started to collect raw data, allowing the researchers, led by physicist and astronomer Shelly Wright from UC San Diego, to test the new design. It’s a modest start, as the entire array could eventually consist of hundreds of telescopes.
This project is a collaboration between UC San Diego, UC Berkeley, University of California Observatories, and Harvard University, the purpose of which is to build a dedicated optical SETI observatory capable of scanning the entire observable sky. The system will undoubtedly be used to observe natural phenomena, such as fast radio bursts—mysterious pulses of energy emanating from outside our galaxy. PANOSETI could also be used to study pulsars, evaporating primordial black holes, among other known and unknown celestial phenomena.
That’s all fine and well—and certainly very important—but the real purpose of PANOSETI is to detect alien signals. Unlike radio SETI, these telescopes will seek out brief but powerful flashes of optical light, as well as quick bursts of infrared radiation.
Traditional radio SETI, which has been around since the 1960s (and was featured in the 1997 sci-fi film Contact), seeks to detect radio leakage and deliberate radio signals from extraterrestrial sources. Optical SETI is similar, but its primary focus is on light, such as short bursts of laser beams. Laser light doesn’t tend to degrade with distance like radio waves do, making it an ideal signal source for an alien civilization seeking to make contact with their own extraterrestrial neighbors (here on Earth, we refer to this approach as METI—messages to extraterrestrial intelligence). Such laser light could arrive in the form of Morse Code-like pulses suggestive of artificial rather than natural origin.
“It’s hard to predict what other civilizations might be doing, what kind of technology they might use for communication, navigation, planetary protection, and how we can detect their presence, so the best strategy in SETI is a multiple strategy, to look for lots of different types of signals and artifacts of ET’s technology,” explained Dan Werthimer, a PANOSETI team member and chief technologist at UC Berkeley’s SETI Research Center, in an email to Gizmodo. He added that “radio is good for omnidirectional communication, lasers are good for point-to-point high data rate communication.”
PANOSETI will also be capable of detecting infrared radiation (IR), which could help with the detection of extraterrestrial Dyson spheres—hypothetical megastructures popularized by the late Freeman Dyson. Built by advanced aliens, these massive structures would envelope an entire star for the purpose of extracting solar energy. These structures would not be completely invisible from the outside, as they would leak infrared radiation at certain bands. PANOSETI could, in theory, detect this infrared light. Werthimer cautioned that the system “isn’t designed specifically with megastructures in mind.” He said it’s “possible” that PANOSETI might be used in this way, but the system works best at detecting short flashes of light, rather than slow infrared leakage.
Whether optical or infrared, however, proving these signals come from an alien source would pose a different set of challenges altogether; but that’s another story. Of course, we don’t know if aliens exist or if any sort of SETI strategy is capable of detecting aliens, but we have to try. That intelligent life might exist elsewhere in the galaxy is one of the most profound unanswered questions of the human condition.
PANOSETI will perform exhaustive searches at unprecedented resolutions. The system will be able to detect signals at nanosecond time scales (a billionth of a second!), and scan the entire observable sky. Each telescope will watch a patch of sky measuring 10 degrees by 10 degrees (by comparison, the Moon takes up around 0.5 degrees of sky), hence the need for multiple observatories.
Once online and fully operational, the system will gaze into largely unexplored space.
“Most SETI is at radio frequencies, and very little has been done at visible and IR, very little at billionth-of-a-second time scales, and none with a wide field of view like PANOSETI that can detect rare events,” Werthimer told Gizmodo. “Most SETI searches look at a millionth of the sky at a time—like looking through a straw—so if the signal isn’t on all the time, it’s almost impossible to detect [signals] if you can only observe a small part of the sky at a time.”
The PANOSETI team is still considering possible locations for the array. Werthimer hinted that Palomar Observatory in San Diego is a leading candidate, and that, ideally, they’d place “a pair of domes in the southern hemisphere and on the other side of our planet.” Construction is scheduled to start in 2021.
In closing, I have a message for laser-emitting aliens. Show yourself! We now have the power to detect you.