On August 24, 2022, SETI, the Search for Extraterrestrial Intelligence, announcement that his telescope, the Allen Telescope Array (ATA), had detected signs of intelligence. These signs came from NASA’s Voyager 1 spacecraft, the furthest man-made object from Earth. The ATA has been undergoing an upgrade since 2019, and on July 9, 2022, as part of a test of its new capabilities, it was able to detect the Voyager 1 carrier signal.
As of this writing, nearly 45 years after launch, Voyager 1 is about 23.4 billion km (14.6 billion miles) from Earth. Voyager 1, along with its twin Voyager 2, is on a mission to explore the limits of the heliosphere and the interstellar medium.
Wael Farah is radio scientist for SETI. Farah spoke to EarthSky about this “discovery” of the Voyager 1 signal, and what it could mean for finding intelligent life in space which is not From land.
SETI Telescope, the Allen Telescope Network
The Allen Telescope Array (ATA) is unique, designed specifically to search for extraterrestrial intelligence. The name of the telescope network comes from donor Paul Allen, co-founder of Microsoft. These 42 radio antennas are located at Hat Creek Observatory, about 300 miles north of San Francisco.
As of 2019, the ATA is undergoing upgrades. To test the success of the ATA upgrades, Farah set out to find intelligent life as we know it… Voyager 1. Farah explained why he set out to find this brave spacecraft from the 70s:
Voyager 1 is currently the furthest man-made object from our home planet. Also, Voyager’s signature is quite similar to what we’re trying to look for when performing SETI radio science. Therefore, it is quite natural to try to observe and detect this particular space probe.
Discovering Voyager 1
EarthSky asked Farah how it felt to “discover” Voyager 1 with the upgraded ATA. Fara said:
It was indeed absolutely like making a discovery. Although we knew relatively well where to look for it, finding the signal was no easy feat, like any other scientific discovery. It was a moment of relief when I saw this little line appear on my computer screen. It represents the culmination of three years of hard work by a relatively small team of which I am a very proud member.
From Voyager 1 to extraterrestrial intelligence?
EarthSky asked Farah what the success of the Voyager signal discovery means for ATA’s ability to find intelligent life in the universe that is not ours. fara replied
Detecting Voyager gives us confidence in our ability to find other artificial signals. One way to do SETI radio is to search for narrowband transponders or beacons from other worlds, just like the transponder Voyager has on board. Now, one can test their observing setup with simulated and fake data, but nothing is better than a real signal. If we are able to pick up Voyager’s carrier with the ATA, we build our confidence that we can blindly detect a similar artificial signal from somewhere in our galaxy.
Detecting intelligence beyond Voyager 1
Voyager 1 is just outside our solar system, about 14 billion miles (23 billion km) from Earth at the time of this writing. EarthSky asked Farah: to find an alien probe drifting through space with the ATA, would it have to be within range of Voyager 1 (drift through or near our solar system)? Fara said:
Although possible, it is not necessary. It all depends on the strength of the transmitter we are looking for. Obviously a beacon halfway through our galaxy has to be a few orders of magnitude brighter than Voyager 1’s emitter (due to the inverse square law of the force of light propagation) to be detectable. Such powerful transmitters are already within our current technological capabilities, and so it’s fair to assume that ET could use them.
What if a SETI telescope ever detects intelligence?
Finally, EarthSky asked Farah what it would mean for the world if the ATA ever picked up a smart signal. Fara said:
The ATA would respond to ‘Are we alone?’ question, a question that we, as a human species, are deeply committed to answering. Detecting life beyond our planet would certainly be a huge discovery, probably the biggest in a century. It could happen in the next two, five, 10 or maybe 50 years, but I personally hope I’ll be there when it happens. And we have a good chance (!) given the technological advances in hardware and software.
Conclusion: The SETI telescope known as the Allen Telescope Array has detected the signal from Voyager 1 in interstellar space. EarthSky thanks SETI astronomer Wael Farah for helping us understand what it means to find intelligence in our galaxy.
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