SETI: Breakthrough Listen Expands the Search

The SETI effort run by Breakthrough Listen is beginning to hit on all cylinders. Yesterday came news that observations at the CSIRO Parkes Radio Telescope in New South Wales have been extended. You may recall that work at the site began in November of 2016, when Parkes joined the Green Bank Telescope (GBT) in West Virginia, USA, and the Automated Planet Finder (APF) at Lick Observatory in California in Breakthrough’s search for extraterrestrial signals.

Invariably, when I start talking about SETI, I recall James Gunn’s masterful The Listeners, written in 1972 but made up of previously published stories on the topic that Gunn melded together with interesting transitions. Here we get a tale of the first detection of a genuine extraterrestrial civilization, the narrative mixing with not just news reports but quotes on SETI and related matters from scientists to philosophers (the technique always reminds me of Dos Passos, but as I’ve written before, a science fiction reference is John Brunner’s Stand on Zanzibar). Carl Sagan would tell Gunn that The Listeners had been one of the many inspirations that drew him to write his own novel Contact.

But back to Parkes. The initial Breakthrough work there used software similar to the Green Bank Telescope’s, examining southern skies not accessible from the latter. In an obviously symbolic gesture, ‘first light’ at Breakthrough’s Parkes operation involved a close look at Proxima Centauri b, not long after its discovery. At that time, Andrew Siemion, director of UC Berkeley SETI Research Center, explained the Proxima observation this way:

“The chances of any particular planet hosting intelligent life-forms are probably minuscule. But once we knew there was a planet right next door, we had to ask the question, and it was a fitting first observation for Parkes. To find a civilization just 4.2 light years away would change everything.”

And while no one expected to find it there, the symmetry between this symbolic first act and Breakthrough Starshot’s design studies for an interstellar probe targeting nearby stars was obvious. In yesterday’s announcement, we learned that the Parkes survey is now broadening substantially, using new digital instrumentation to capture the vast incoming dataflow from the Parkes multibeam receiver. Earlier efforts at the observatory could observe a single point on the sky at any one time, whereas the multibeam receiver puts 13 beams into the effort.

The result: An effort that will encompass large areas of sky covering all the galactic plane visible from the Parkes site. Scientists and engineers from the University of California, Berkeley SETI Research Center (BSRC) have expanded the Breakthrough Listen back-end so that it can manage 130 gigabits per second — 100 million radio channels scanned for each of the 13 beams. The Parkes instrument will see 1500 hours of Breakthrough Listen observing time in 2018.

We’re talking 100 petabytes of raw data here, out of which must be untangled the usual RFI interference ranging from aircraft to satellites, terrestrial cell towers and other background noise. A recent news release from Breakthrough Listen points to the improved rejection of RFI signals generated by Earthside technologies as a complement to the project’s improved survey speeds. The new methods will be applied not just to SETI but fast radio bursts (FRBs) as well.

“With these new capabilities,” says Danny Price, Parkes project scientist with the Breakthrough Listen project at UC-Berkeley, “we are scanning our Galaxy in unprecedented detail. By trawling through these huge datasets for signatures of technological civilizations, we hope to uncover evidence that our planet, among the hundreds of billions in our galaxy, is not the only one where intelligent life has arisen.”

Image: The Parkes 64m radio telescope in Parkes, New South Wales. Credit: Daniel John Reardon CC BY-SA 4.0, from Wikimedia Commons.

All told, Breakthrough Listen aims to search one million nearby stars along with the entire galactic plane and 100 nearby galaxies in radio and optical wavelengths. Mining the data trove is a huge undertaking, within which signal detection and classification is an ongoing challenge. The expanded Parkes dataset will be made available to the public online, which gives those with programming skills the opportunity to work on the critical algorithms needed to screen interference from what could potentially be the traces of an extraterrestrial transmission.