AI discovers mysterious radio bursts that could originate from an alien source
Image credit: Breakthrough Listen image
Mysterious radio wave bursts from a distant galaxy have been discovered by an artificial intelligence program developed by University of California, Berkeley researchers.
The team, who are working under the Breakthrough Listen project for the search for intelligent life in the universe (SETI), discovered 72 new fast radio bursts from the source, which is about three billion light years from Earth.
Fast radio bursts are bright pulses of radio emission mere milliseconds in duration, thought to originate from distant galaxies.
The source of these emissions is still unclear, although theories range from highly magnetised neutron stars blasted by gas streams from a nearby supermassive black hole, to suggestions that the burst properties are consistent with signatures of technology developed by an advanced civilisation.
“This work is exciting not just because it helps us understand the dynamic behaviour of fast radio bursts in more detail, but also because of the promise it shows for using machine learning to detect signals missed by classical algorithms,” said Andrew Siemion, director of the Berkeley SETI Research Center.
Breakthrough Listen is also applying the successful machine-learning algorithm to find new kinds of signals that could be coming from extra-terrestrial civilisations.
While most fast radio bursts are one-offs, the source here, FRB 121102, is unique in emitting repeated bursts. This behaviour has drawn the attention of many astronomers hoping to pin down the cause and the extreme physics involved in fast radio bursts.
The AI algorithms dredged up the radio signals from data were recorded over a five-hour period on 26 August 2017, by the Green Bank Telescope in West Virginia.
An earlier analysis of the 400 terabytes of data employed standard computer algorithms to identify 21 bursts during that period. All were seen within one hour, suggesting that the source alternates between periods of quiescence and frenzied activity, said Berkeley SETI postdoctoral researcher Vishal Gajjar.
UC Berkeley PhD student Gerry Zhang and collaborators subsequently developed a new, powerful machine-learning algorithm and reanalysed the 2017 data, finding an additional 72 bursts not detected originally. This brings the total number of detected bursts from FRB 121102 to around 300 since it was discovered in 2012.
“This work is only the beginning of using these powerful methods to find radio transients,” said Zhang. “We hope our success may inspire other serious endeavours in applying machine learning to radio astronomy.”
Zhang’s team used some of the same techniques that internet technology companies use to optimise search results and classify images. They trained an algorithm known as a convolutional neural network to recognise bursts found by the classical search method used by Gajjar and collaborators, and then set it loose on the dataset to find bursts that the classical approach missed.
“Whether or not FRBs themselves eventually turn out to be signatures of extra-terrestrial technology, Breakthrough Listen is helping to push the frontiers of a new and rapidly growing area of our understanding of the Universe around us,” he said.
In July Japanese researchers kitted out a telescope with a new instrument that uses infrared light to find alien planets.