Be seeing you...
IN 1959 a young astronomer called Frank Drake was working at the Green Bank radio observatory in West Virginia. Thinking about the capabilities of the 26-metre dish under construction there, he realised that, if it were used to transmit radio waves rather than to receive them, it would produce a signal that a similar telescope on a planet orbiting another star would be able to pick up. For the first time, human beings had a technology for communicating with other solar systems—an idea which led immediately to the speculation that, if there were any aliens out there, they might already be doing something similar.
Dr Drake put his idea to three colleagues over burgers at a nearby diner. Two were distinctly unimpressed. The third, a physicist of far-reaching interests called Lloyd Berkner, was enthusiastic. And since Berkner—who had a reputation as an “optimistic gambler”, Dr Drake recalled in his memoirs—was the one who controlled the money, Dr Drake got to carry out his search. In 1960 he spent 150 hours pointing the Green Bank telescope at two nearby stars, Tau Ceti and Epsilon Eridani, and scanning for signals. Thus began the search for extraterrestrial intelligence, or SETI.
Five and half decades on, Dr Drake joined Stephen Hawking, a physicist, and Martin Rees, Britain’s Astronomer Royal, to launch Breakthrough Listen, the latest incarnation of the search. It is an undertaking that would have seemed unbelievable back then. As of 2016, an unprecedented 15% of the observing time at Green Bank’s latest dish—which at 100 metres across has 15 times the area of its first—will be devoted to seeking signals from aliens. Rather than looking at just two stars, Breakthrough Listen will observe the nearest 1m, as well as looking more generally in the core and disc of the Milky Way, and 100 other galaxies to boot. Later in 2016 the project will add the 64-metre dish at the Parkes Observatory, in Australia, to its workforce. In time, further observatories will be pressed into service. Back in 1960, Dr Drake could listen in to just one radio channel at a time. The new effort will use cutting-edge electronics to scan some 10 billion simultaneously.
Many such searches, most privately funded, have been attempted before. But Breakthrough Listen will have 50 times the sensitivity of any previous effort, will cover much more of both the sky and the radio spectrum, and will also use an optical telescope to search systematically for laser transmissions, should they turn out to be E.T.’s preferred mode of discourse. All of the petabytes of resulting data will be freely available for anyone with an internet connection to analyse. The team behind Breakthrough Listen says it will do as much searching every day as any of the previous projects managed in a year.
Let the dice fly high
The optimistic gambler responsible for this new effort is Yuri Milner, a Russian entrepreneur and investor who has made a fortune in Silicon Valley. Mr Milner has a background in physics and a long-standing interest in space. Indeed, his parents named him after Yuri Gagarin—who, in the year of Mr Milner’s birth, became the first human to orbit the Earth. In 2012 Mr Milner helped found the Breakthrough prizes, awarded to researchers who have helped answer big questions in biology, physics and maths. Convinced that the existence of extraterrestrial life is the biggest question of all, he has committed $100m over ten years to Breakthrough Listen.
Mr Milner reckons there are three reasons why the moment is right to go big on SETI. One is that Kepler, a space telescope run by NASA, has shown that there are a lot of potentially habitable planets out there. Geoff Marcy, an astronomer at the University of California, Berkeley, who will run Breakthrough Listen, says Kepler-based studies suggest that perhaps one star in ten has planets that are “Earth-sized and lukewarm”—not obviously too massive, too hot or too cold for vaguely Earthlike life.
The second reason is the relentless rise of signal-processing power. The ten-billion-channel system Dr Marcy is working on would have been impossible just a few years ago. That all of the resulting data can easily be made available to other scientists and enthusiastic amateurs is another sign of progress. Some 3m people already participate in the SETI@Home project, which lets people use spare computing time to sift through previous SETI data. Since the project has now linked up with Breakthrough Listen, more will surely join it. Free access to data will almost certainly generate false alarms, but Dr Marcy accepts that as part of the price of doing business.
A third motive for the push is that an unprecedented amount of time is now available on first-rate radio telescopes. Government-funded research has seen its purse-strings drawn tight recently, and instruments like that at Green Bank need new sources of income.
Nevertheless, hunting for aliens will always be a long-odds bet. Breakthrough Listen will surely discover some interesting pulsars, quasars and other, possibly novel, natural phenomena, but it could get through its $100m with no SETI results at all, and no clear sense of whether another $100m would be likely to change the matter. That, and the fear of ridicule from those who question the very notion of alien-hunting, has made governments reluctant to pay for SETI, despite its demonstrable appeal to many taxpayers.
Breakthrough Listen is not the only initiative that Mr Milner has in mind. It already has one offshoot, Breakthrough Message—a competition challenging people to create a message by which humans might announce themselves to the outside world. The prize fund for that is $1m, though as yet there is no promise any message will actually be transmitted. Mr Milner thinks there is a debate to be had before deciding on such a course of action.
And life in the universe is a question that can be approached in other ways. Mr Milner recently hired Pete Worden, a retired American air force general and an astronomer by training, to run his projects. Both at the Pentagon, where he worked on the “Star Wars” missile-defence programme, and as boss of the research centre that is home to Kepler, Mr Worden has championed small, innovative space missions. It seems likely, then, that future bids to answer Mr Milner’s questions about life in the universe will employ a more Kepler-like approach—looking for promising nearby planets from orbit. As they say in SETI circles, watch this space.
Note: An earlier version of this story was first published online on July 20th. It has been slightly edited for length for inclusion in the print edition.