The mysterious radio signal that researchers thought may have emanated from the closest star to Earth, Proxima Centauri, was likely nothing more than a ‘false positive,’ scientists announced late Monday.
Researchers from the Breakthrough Listen Initiative said the ‘intriguing’ signal that was picked up in 2020 is likely just an ‘an artifact of Earth-based interference from human technologies.’
Dr Sofia Sheikh, a researcher with the Listen team, looked at the data set for the signals and found they are spaced at ‘regular frequency intervals.’
The intervals appear to correspond to multiples of frequencies used by oscillators commonly used in electronic devices.
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The radio signal researchers thought came from Proxima Centauri (pictured) is likely nothing more than a ‘false positive’
The signal, picked up in 2020, is likely just an ‘an artifact of Earth-based interference from human technologies.’ Pictured, a not-to-scale representation of how far away Proxima B is from Earth compared to Voyager 1, the farthest man-made object which was launched in 1977
The researchers scanned the Proxima Centauri star system across a wide range of frequencies, from 700 megahertz to 4 gigahertz
Four million hits that were eventually whittled away to 1 million after looking at hits with no motion
The researchers scanned the Proxima Centauri star system across a wide range of frequencies, from 700 megahertz to 4 gigahertz ‘(in other words, performing the equivalent of tuning to over 800 million radio channels at a time,’ according to a statement) and found 4 million hits that were eventually whittled away to 1 million after looking at hits with no motion.
Another filter was applied for the remaining hits, as they had to appear to come from the direction of Proxima Centauri.
The researchers pointed the Parkes Telescope at the star and then pointed it away, toggling between the ‘on-off’ pattern several times, which left them with 5,160 possible candidates.
After weeding out more signals, there was one – known as BLC1 – that had ‘characteristics broadly consistent with hypothesized technosignatures,’ but it too is likely just a case of human technology.
‘Taken together, this evidence suggests that the signal is interference from human technology, although we were unable to identify its specific source,’ Sheikh said in a statement.
After weeding out signals, there was one, known as BLC1 (pictured), that had ‘characteristics broadly consistent with hypothesized technosignatures,’ but it too is likely just a case of human technology
Proxima Centauri is 4.2 light years from Earth and has two confirmed planets, a gas giant (Proxima c) and a rocky world, known as Proxima b. Artist’s rendering of Proxima Centauri system. Proxima c orbits in about 5.2 years around Proxima Centauri and Proxima b, on the left, was discovered in 2016 that orbits in the ‘habitable zone’ closer than Mercury is to the Sun
Proxima b: The nearest exoplanet to the Earth
Proxima b is the nearest exoplanet to the Earth and the closest planet to the star Proxima Centauri.
It orbits within the habitable zone of the star – but as Proxima Centauri is a red dwarf and much smaller than the Sun this zone is very close to the star.
Proxima b orbits its star every 11.2 Earth days and has a mass of about 1.2 times that of the Earth.
The rocky world is subject to solar winds 2,000 times those experienced on Earth from the Sun.
While it is within a zone where liquid water could form – these stellar winds make it unlikely life could evolve.
The planet was discovered in August 2016 and is likely tidally locked.
For these reasons, despite being in the habitable zone, its actual habitability has not been established.
Studies have suggested the planet could have surface oceans and a thin atmosphere, but that hasn’t been confirmed.
Astronomers won’t know if it has water or an atmosphere until it can be seen transiting in front of its star – which has yet to happen.
If water and an atmosphere are present, even with the extensive radiation, it could be possible life has developed on the planet.
Scientists hope the James Webb Space Telescope – due to come online next year – could detect the atmosphere of Proxima Centauri b.
There is also a theoretical mission to send a probe to the planet in 2069 to search for biosignatures.
‘The original signal found by Shane Smith is not obviously detected when the telescope is pointed away from Proxima Centauri – but given a haystack of millions of signals, the most likely explanation is still that it is a transmission from human technology that happens to be “weird” in just the right way to fool our filters.’
The radio wave signal was initially detected in April and May 2019 from the Australia-based Parkes Telescope at a frequency of 980 MHz.
Last year, members of the Breakthrough Listen Project – a $100 million initiative to find alien life through radio telescopes – ‘carefully investigated’ the mysterious signal that emanated from the star system.
The project, founded by Israeli billionaire Yuri Milner, looks for evidence of extraterrestrial ‘technosignatures’ – radio waves and other evidence of extraterrestrial technology.
Milner launched the initiative in 2015 to look for stray or intentional alien signals and designed to last a decade.
Proxima Centauri is 4.2 light years from Earth and has two confirmed planets, a Jupiter-like gas giant and a rocky world called Proxima b in the habitable zone.
The signal was spotted by the Parkes Telescope in Australia in early 2020, but unlike previous radio bursts, had not been attributed to any Earth-based or near-Earth human-created source at the time.
After the researchers performed their deep dive into the signal, they found that it likely did not come from Proxima Centauri.
‘In the case of this particular candidate,’ Andrew Siemion, who leads Listen’s science team said, adding, ‘our analysis suggests that it’s highly unlikely that it is really from a transmitter out at Proxima Centauri.
‘However, this is undoubtedly one of the most intriguing signals we’ve seen to date.’
The news is disappointing to some, but the findings may offer hope as experts continue to tweak the process and continue to search for signs of life.
‘While we were unable to conclude a genuine technosignature, we are increasingly confident that we have the necessary tools to detect and validate such signatures if they exist,’ Breakthrough Initiatives executive director Dr S. Pete Worden said.
KEY DISCOVERIES IN HUMANITY’S SEARCH FOR ALIEN LIFE
Discovery of pulsars
British astronomer Dame Jocelyn Bell Burnell was the first person to discover a pulsar in 1967 when she spotted a radio pulsar.
Since then other types of pulsars that emit X-rays and gamma rays have also been spotted.
Pulsars are essentially rotating, highly magnetised neutron stars but when they were first discovered it was believed they could have come from aliens.
‘Wow!’ radio signal
In 1977, an astronomer looking for alien life in the night sky above Ohio spotted a radio signal so powerful that he excitedly wrote ‘Wow!’ next to his data.
In 1977, an astronomer looking for alien life in the night sky above Ohio spotted a radio signal so powerful that he excitedly wrote ‘Wow!’ next to his data
The 72-second blast, spotted by Dr Jerry Ehman through a radio telescope, came from Sagittarius but matched no known celestial object.
Conspiracy theorists have since claimed that the ‘Wow! signal’, which was 30 times stronger than background radiation, was a message from intelligent extraterrestrials.
Fossilised Martian microbes
In 1996 Nasa and the White House made the explosive announcement that the rock contained traces of Martian bugs.
The meteorite, catalogued as Allen Hills (ALH) 84001, crashed onto the frozen wastes of Antarctica 13,000 years ago and was recovered in 1984.
Photographs were released showing elongated segmented objects that appeared strikingly lifelike.
Photographs were released showing elongated segmented objects that appeared strikingly lifelike (pictured)
However, the excitement did not last long. Other scientists questioned whether the meteorite samples were contaminated.
They also argued that heat generated when the rock was blasted into space may have created mineral structures that could be mistaken for microfossils.
Behaviour of Tabby’s Star in 2005
The star, otherwise known as KIC 8462852, is located 1,400 light years away and has baffled astronomers since being discovered in 2015.
It dims at a much faster rate than other stars, which some experts have suggested is a sign of aliens harnessing the energy of a star.
The star, otherwise known as KIC 8462852, is located 1,400 light years away and has baffled astonomers since being discovered in 2015 (artist’s impression)
Recent studies have ‘eliminated the possibility of an alien megastructure’, and instead, suggests that a ring of dust could be causing the strange signals.
Exoplanets in the Goldilocks zone in 2017
In February 2017 astronomers announced they had spotted a star system with planets that could support life just 39 light years away.
Seven Earth-like planets were discovered orbiting nearby dwarf star ‘Trappist-1’, and all of them could have water at their surface, one of the key components of life.
Three of the planets have such good conditions, that scientists say life may have already evolved on them.
Researchers claim that they will know whether or not there is life on any of the planets within a decade, and said: ‘This is just the beginning.’