Astronomers behind the most extensive search yet for alien life are investigating an intriguing radio wave emission that appears to have come from the direction of Proxima Centauri, the nearest star to the sun.
The narrow beam of radio waves was picked up during 30 hours of observations by the Parkes telescope in Australia in April and May last year, the Guardian understands. Analysis of the beam has been under way for some time and scientists have yet to identify a terrestrial culprit such as ground-based equipment or a passing satellite.
It is usual for astronomers on the $100m (£70m) Breakthrough Listen project to spot strange blasts of radio waves with the Parkes telescope or the Green Bank Observatory in West Virginia, but all so far have been attributed to human-made interference or natural sources.
The latest “signal” is likely to have a mundane explanation too, but the direction of the narrow beam, around 980MHz, and an apparent shift in its frequency said to be consistent with the movement of a planet have added to the tantalising nature of the finding. Scientists are now preparing a paper on the beam, named BLC1, for Breakthrough Listen, the project to search for evidence of life in space, the Guardian understands.
The beam that appears to have come from the direction of Proxima Centauri, a red dwarf star 4.2 light years from Earth, has not been spotted since the initial observation, according to an individual in the astronomy community who requested anonymity because the work is ongoing. “It is the first serious candidate since the ‘Wow! signal’,” they said.
The “Wow! signal” was a short-lived narrowband radio signal picked up during a search for extraterrestrial intelligence, or Seti, by the Big Ear Radio Observatory in Ohio in 1977. The unusual signal, which gained its name after astronomer Jerry Ehman wrote “Wow!” next to the data, unleashed a wave of excitement, though Ehman cautioned about drawing “vast conclusions from half-vast data”.
Launched in 2015 by Yuri Milner, a science and technology investor based in Silicon Valley, the Breakthrough Listen project eavesdrops on the million stars closest to Earth in the hope of detecting stray or intentional alien broadcasts. The 10-year effort was announced at the Royal Society in London when the late Stephen Hawking called the work “critically important”. Speaking at the event, Hawking, who saw humanity’s future in the stars, said: “Mankind has a deep need to explore, to learn, to know. We also happen to be sociable creatures. It is important for us to know if we are alone in the dark.”
The challenge for astronomers on Breakthrough Listen, and others devoted to finding intelligent life in the heavens, is to spot potential “technosignatures” among the relentless babble of radio waves from equipment on Earth, natural cosmic phenomena, and orbiting hardware that circles the planet. It is no easy task. In 1997 the US alien hunter Jill Tarter, who inspired the character of Ellie Arroway in the movie Contact, detected a potential signal but it was later found to be broadcasts from an antenna on the Soho spacecraft, a joint mission to observe the sun by Nasa and the European Space Agency.