Construction is about to begin on a vast range of telescopes dedicated to detecting natural and artificial sources of optical and infrared light. Once operational, the system, called PANOSETI, will be able to scan the entire sky, significantly increasing our chances of detecting laser or other signals from other planets.
In development since 2018, PANOSETI, which stands for Optical Infrared SETI (Search for ExtraTerrestrial Intelligence), consists of two prototype telescopes positioned at the Lick Observatory near San Jose, California. Telescopes that began to collect raw data, allowing researchers, led by physicist and astronomer Shelly Wright, to test the new project.
It's a small start: the entire array could eventually consist of hundreds of telescopes.
This project is a collaboration between UC San Diego, UC Berkeley, University of California and Harvard. The aim is to build a SETI optical observatory capable of scanning the entire observable sky.
The system will be used to observe natural phenomena such as fast radio bursts, mysterious pulses of energy emanating from outside our galaxy. PANOSETI can also be used to study Pulsars and other known and unknown celestial phenomena.
All very important, but the real purpose of PANOSETI is to detect alien signals.
Unlike radio SETI, these telescopes will look for short but powerful bursts of optical light, as well as rapid bursts of infrared radiation.
Traditional SETI, born in the 60s (and featured in “Contact,” the 1997 film), seeks to detect intelligent radio signals from extraterrestrial sources.
PANSETI is similar, but its main focus is on light, like the short flashes of laser beams.
Laser light does not degrade with distance as radio waves do, and is therefore an ideal signal source for an alien civilization trying to make contact with its extraterrestrial neighbors. Such laser light could arrive in the form of Morse Code-like pulses suggesting artificial rather than natural origin.
“It's hard to predict what other civilizations might do. What kind of technology could they use for communication, navigation, planetary protection and how can we detect their presence. This is why the best strategy in SETI is a multiple strategy, to search for different types of signals and artifacts of possible extraterrestrial technology."
He explained it Dan Werthimer, a member of the PANOSETI team and chief technologist at UC Berkeley's SETI Research Center. He added that “radio is good for omnidirectional communication, lasers are good for point-to-point high data rate communication.”
That intelligent life can exist elsewhere in the galaxy is one of the deepest unanswered questions of the human condition.
Hunting for Dyson orbs
PANOSETI will also be able to detect infrared (IR) radiation, which could help detect extraterrestrial Dyson spheres – hypothetical megastructures popularized by the late Freeman Dyson.
Built by advanced civilizations, these enormous structures would envelop 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 in certain bands. PANOSETI could, in theory, detect this infrared light.
Werthimer cautioned that the system is “not designed specifically with megastructures in mind.” He adds that it is "possible" that PANOSETI could be used in this way, but the system works better for detecting short flashes of light, rather than slow dispersion of infrared.
Whether optical or infrared, proving that these signals are coming from an alien source would bring an entirely different set of challenges; but that's another story.
Of course, we don't know if aliens exist or if any type of SETI strategy is capable of detecting aliens, but we have to try.
PANOSETI will perform exhaustive searches at unprecedented resolutions. The system will be able to detect signals on nanosecond time scales (one billionth of a second!) and scan the entire observable sky. Each telescope will observe a patch of sky measuring 10 degrees by 10 degrees (by comparison, the Moon takes up about 0,5 degrees of sky).
Once online and fully operational, the system will look into a largely uncharted space.
PANOSETI: with eyes wide open
Most SETIs are focused on radio frequencies and very little has been done at the visible and IR level, very little at the billionth of a second scale, and none with a wide field of view like PANOSETI can detect rare events.
“Most SETI searches look at one millionth of the sky at a time,” says Werthimer. It's like looking through a straw: if the signal is not always active it is almost impossible to detect it by observing only a small part of the sky at a time. “
The PANOSETI team is still evaluating possible locations of the array. Werthimer has hinted that San Diego's Palomar Observatory is a leading candidate. They should set up “a couple of satellite dishes in the southern hemisphere and on the other side of our planet.” Construction is scheduled to begin in 2021.
