'Very Weird' Radio Signals Turn Out to Be Very Human

Scientists: 2019 signals picked up by telescope at Parkes Observatory were form of radio interference
By Jenn Gidman,  Newser Staff
Posted Oct 26, 2021 7:23 AM CDT
Sorry, Those 'ET' Radio Signals Were Actually From Humans
This artist rendering shows a view of the surface of the planet Proxima Centauri b orbiting the red dwarf star Proxima Centauri, the closest star to our solar system.   (European Southern Observatory via AP)

If you were hoping we'd soon get to meet our neighbors from an Earth-like planet more than 4 light-years away, we'll be waiting a little longer. More than two years ago, researchers using the Murriyang radio telescope at Australia's Parkes Observatory were excited to pick up "promising" radio signals that appeared to be coming from one of two planets circling Proxima Centauri, the red dwarf star that's the closest star to our sun, reports the Guardian. That planet, Proxima Centauri b, is believed to possibly be suitable for life—but in two new papers published in the Nature Astronomy journal, scientists say the 2019 signals weren't some sort of extraterrestrial communication, but an "electronically drifting intermodulation product of local, time-varying interferers aligned with the observing cadence."

In layman's terms: It's human-made, though the researchers still haven't pinpointed exactly where the signals came from. ABC Australia explains that Proxima Centauri b is on a list of subjects to study by the Berkeley SETI Research Center's Breakthrough Listen project, a $100 million program on the hunt for "technosignatures"—signals deemed not human-made or explained by astronomical events. The April 2019 event was the project's first "signal of interest" to examine, and it was an unusual one, as it stayed steady for several hours and seemed to only emerge when the telescope was directed right at Proxima Centauri for an extended period.

The length of the signal meant it wasn't coming from an airplane, say, or a man-made satellite. The signal also showed a change in frequency called a Doppler shift, which suggested it was coming from a moving planet. Price's team spent months eliminating possible sources, until they finally determined what had happened: It was simply radio frequency interference from humans, with multiple signals mixing together "in a complicated way," as happens in a guitar amp. It's akin to "turning it up to 11," like in This Is Spinal Tap, Danny Price, a co-author on both papers, notes to the Guardian.

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Even though it's now been found that the signal isn't being sent through the cosmos by our alien counterparts, Price and his team still think it's a "very weird" one they haven't quite figured out. One working theory is that it's coming about from high-end clock oscillators, electronic components made up of vibrating crystals that are used in commercial telecommunications devices, radar structures, and even mobile phone towers. "We would love for it to have been a technosignature," Price tells the Guardian, calling it, at the very least, an "excellent case study" and adding, per ABC. "It's a big universe and we've only just scratched the surface." (This kind of disappointment has happened before.)

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