The construction of a wide range of telescopes dedicated to the detection of natural and artificial sources of optical and infrared light is about to start. 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 infrared optical SETI (Search for ExtraTerrestrial Intelligence), consists of two prototypes of telescopes positioned at the Lick Observatory near San Jose, California. Telescopes that started collecting raw data, allowing researchers, led by the physicist and astronomer Shelly Wrigh, to test the new project.
It's a small start: the whole array could eventually be made up 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 explosions, mysterious energy impulses emanating from outside our galaxy. PANOSETI can also be used to study Pulsar 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.
The traditional SETI, born in the 60s (and described 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. This laser light could come in the form of pulses similar to the Morse Code which suggest the artificial origin rather than the natural one.
“It is difficult to predict what other civilizations could do. What kind of technology they could use for communication, navigation, planetary protection and how we can detect their presence. For this 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 "The radio is good for omnidirectional communication, lasers are good for high-speed point-to-point data 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 Dyson's extraterrestrial spheres - hypothetical megastructures popularized by the late Freeman Dyson.
Built by advanced civilizations, these huge structures would wrap an entire star in order to extract solar energy. These structures would not be completely invisible from the outside, as they would lose infrared radiation in certain bands. PANOSETI could, in theory, detect this infrared light.
Werthimer warned that the system "is not specifically designed 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 a slow dispersion of infrared.
Whether optical or infrared, proving that these signals come from an alien source would bring a completely 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 (in comparison, the Moon occupies 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 research looks at one millionth of heaven at a time," says Werthimer. It is 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 the possible positions of the array. Werthimer he hinted that San Diego's Palomar Observatory is a prominent candidate. They should fix "a couple of parables in the southern hemisphere and on the other side of our planet." Construction is expected to start in 2021.
