The search for extraterrestrial intelligence gets a new home at Oxford

The University of Oxford in the United Kingdom has been selected as the new international headquarters for the world's largest SETI project, the Breakthrough Listen initiative.

SETI, which stands for the Search for Extraterrestrial Intelligence, received a huge boost in 2015 with the launch of Breakthrough Listen. This $100-million-dollar private venture by the Breakthrough Initiatives foundation focuses on searching for technosignatures, signals from or indications of technologically-advanced extraterrestrial species. 

Breakthrough Listen has previously been headquartered at the University of California, Berkeley, but the new international headquarters at the Department of Physics at Oxford will take better advantage of the Square Kilometer Array (SKA), which is a huge array of radio dishes and antennas in South Africa and Australia. 

The SKA should be operational by around 2030. It will transform radio astronomy, observing the radio sky with 50 times the sensitivity of other radio-telescope arrays, and will be capable of surveying the sky 10,000 times faster. Physicists at Oxford have played a leading role in building hardware and writing software for the SKA, and will be able to tailor specific instrumentation for SETI. 

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Joining the team at Oxford will Andrew Siemion of the University of California, Berkeley, who has been Breakthrough Listen's Principal Investigator since its inception. "We are delighted to launch a new era of Listen here at Oxford," concluded Breakthrough's Executive Director, Peter Worden. "This collaboration will be a tremendous fusion of knowledge, resources, and passion to understand our place in the cosmos."

"This is an extraordinarily exciting partnership, bringing a large-scale SETI program to the UK," said Rob Fender, who is Oxford's Head of Astrophysics, in a statement. "This move recognizes how the University of Oxford's existing astrophysics programs in radio astronomy instrumentation, astrophysical transients and exoplanetary studies make it the perfect base for Breakthrough Listen."

The timing coincides with Breakthrough Listen's other new partnership with South Africa's MeerKAT array of 64 radio antennas, which has been a technological precursor for the SKA. MeerKAT began listening to a million stars for extraterrestrial radio signals in December 2022.

Breakthrough Listen, like most SETI projects, focuses on searching for radio signals, but it also encompasses technosignatures in general. These are defined as evidence for the activity of technological extraterrestrial species, but SETI astronomers deliberately keep the definition open-ended so as not to allow human biases to rule anything out. For example, one area in which astronomers search for technosignatures is in anomalous astrophysical transients — bursts of energy or light with no obvious explanation, which could potentially originate from extraterrestrial engineering on scales vastly greater than we can conceive. 

Breakthrough Listen scientists will search for anomalous astrophysical transients in data collected as part of the Legacy Survey of Space and Time (LSST) that will be conducted by the Vera C. Rubin Observatory in Chile when it becomes operational in 2024.

Breakthrough Listen also searches for possible "megastructures," giant non-natural objects, in transits detected by the likes of NASA's Transiting Exoplanet Survey Satellite (TESS), with the best example being Tabby's Star, which was revealed in 2015 to be experiencing irregular and very deep dimming events caused by unknown objects passing in front of it and dimming its light. It was later revealed that the objects were huge clouds of dust, but any real megastructures orbiting a star would result in similar transit events.

In particular, the Oxford group will place emphasis on the search for life on the nearest exoplanets. And all of the above will be done by developing new cutting-edge machine-learning algorithms that can analyze large amounts of data faster and in greater detail than more traditional methods.

Already, astronomers have used machine learning to detect eight possible SETI signals in data from the Green Bank radio telescope in West Virginia.

Looking a little further ahead, proposals for a lunar far side radio telescope to be used for SETI will also be developed by scientists at Oxford. The far side of the moon is a radio-quiet area, shielded from all the radio frequency interference put out by human activity on Earth, meaning it can obtain an unprecedented sensitivity for listening for faint radio signals.