Is the cosmos filled with chatty alien civilizations, or is the Earth a lonely spark of life in a sterile universe? The Russian billionaire Yuri Milner wants to know, and has committed to spending at least $100 million to support the search for extraterrestrial intelligence (SETI). Efforts to listen for interstellar messages date back to the 1960s, but funding has often proved as elusive as the aliens themselves. NASA’s SETI efforts, which ran from the 1970s to the 1990s, consumed about $110 million across twenty years, according to the agency’s former chief historian, the astronomer Steven J. Dick, who calls today’s announcement a “sea change” in SETI funding.
Announced today at a press conference in London, Milner’s Breakthrough Listen initiative provides 10 years of funding for what promises to be the most exhaustive and far-seeing SETI program in history when it begins observations in 2016. Breakthrough Listen will be directed by an advisory committee of prominent scientists chaired by Sir Martin Rees, Astronomer Royal to the United Kingdom. The program is accompanied by another related effort, Breakthrough Message, devoted to crafting crowd-sourced messages from humanity that might someday be transmitted out into the cosmos. Both programs will operate through the new Breakthrough Initiatives division of Milner’s Breakthrough Prize Foundation, which awards the world’s most lavish scientific prizes.
“There are absolutely no strings attached” to the funding, Milner said in an interview with . “I am fully committed to this project. If we don’t find anything in ten years, then we’ll just have to extend it for another ten years, and then for another twenty, if necessary. We will just keep going until we know the answer.”
Supercharging the Search
That search, like all others since, turned up little more than the sound of lifeless cosmic static, but it did inspire a meeting that would profoundly influence SETI’s future. In 1961, Drake, Carl Sagan, and other researchers met to devise what came to be known as the “Drake equation,” a linked series of variables meant to estimate the prevalence of talkative technological civilizations in the Milky Way. Though recent findings from NASA’s Kepler space telescope and other planet-hunting projects have revealed that billions of potentially habitable worlds populate our galaxy, the actual answer to the Drake equation remains unknown. Drake’s long-held best guess, however, is that perhaps 10,000 alien civilizations presently exist in the Milky Way.
The challenge, SETI’s proponents say, is finding them. Even if advanced civilizations are all blasting electromagnetic messages between the stars via some vast pan-galactic internet, there are practically endless permutations of possible wavelengths to survey and signaling protocols to consider. And the Milky Way is a very big place, a few hundred billion stars packed into a spiral disk a hundred thousand light-years wide. A signal could come from essentially any part of the sky at any time on any number of possible wavelengths. SETI efforts to date have only garnered a small, scattered amount of time on large radio telescopes, and typically “piggyback” on other scientific observations, passively listening to whatever target other astronomers are investigating. If learning we are not alone is a cosmic jackpot, Drake has said, then for all its existence SETI has been only playing with a few tickets. To date, the quest for talkative aliens has been a bit like searching for fish in the ocean by scooping up a single glass of seawater.
“Breakthrough Listen will be much more than a glass in the sea,” Milner said at the press conference. “We are bringing a completely different scale of technology to the problem.” His $100 million is buying an unprecedented amount of observing time on two of the largest radio telescopes in the world—the Robert C. Byrd Green Bank Telescope in West Virginia, and the Parkes Telescope in Australia. Perched on opposite hemispheres of the planet, both telescopes will work in tandem to provide a view of practically the whole sky.
The project is also contracting with the University of California, Berkeley to develop new, state-of-the-art instruments and digital-signal processing methods, and is buying time on the Automated Planet Finder (APF) at Lick Observatory in California to perform an optical search for messages sent on pulses of laser light. According to Geoff Marcy, an exoplanet hunter at University of California, -Berkeley, who has performed optical SETI work at Lick and other telescopes, the APF will be capable of detecting laser transmissions as low in power as 100 watts from up to 50 light-years away. For perspective, that’s the same power as a standard light bulb in your living room.
Collectively, the three telescopes will monitor a million stars in the Milky Way, the Milky Way’s star-packed galactic plane, and a hundred nearby galaxies. The effort will cover 10 times more of the sky than previous programs, scanning at least five times more of the spectrum a hundred times faster and with 50 times greater sensitivity than past efforts. “This means we can now do in an hour or a day what we used to do in a year,” says UC-Berkeley’s Dan Werthimer, a veteran SETI astronomer and co-founder of SETI@Home, a distributed computing service that sifts SETI data for candidate signals using idle processing power on personal computers. “It’s going to make the searches we did even ten years ago kind of laughable, because the technology has progressed so fast.” SETI capabilities are doubling every year, Werthimer says, as computers, telescopes, and receivers improve. “That gives you a factor of a thousand improvement every ten years, a factor of a million every twenty. So something that we did thirty years ago will be a billion times worse than what we’ll be doing next year.”
Breakthrough Listen has partnered with the SETI@Home project to allow citizen scientists to analyze its most tantalizing datasets, and intends to freely release its data. That torrent of data (and the instruments developed to handle it) could be a windfall not only for alien hunters, but also for all of radio astronomy, which, for a change, will be piggybacking on SETI.
Changing of the Guard
In the aftermath of NASA’s abandonment, private organizations such as the non-profit SETI Institute in California continued programs of their own, sustained by modest research grants and occasional philanthropic donations. In 2007, using some $25 million from Microsoft co-founder Paul Allen, the SETI Institute debuted the Allen Telescope Array (ATA), an assemblage of 42 small telescopes meant for dedicated SETI work. Alas, the money ran out, and plans for expanding the ATA to hundreds of dishes faltered. In recent years the ATA has been occasionally shuttered for lack of funds, and presently limps along on a shoestring budget, often through performing work with a less SETI-centric focus.
Though searching for alien civilizations may be one of the most publicly appealing topics in all of astronomy, it doesn’t pay well, if at all, and attracting new researchers to the fold had been challenging. “There are very few opportunities for promising young scientists to pursue SETI research in graduate school and beyond,” said Andrew Siemion, the director of UC-Berkeley’s SETI Research Center. “This funding helps to communicate to young scientists that a career path in the field is possible.” Siemion is in his thirties, and an outlier in a rarefied field filled with researchers who are senior in all senses of the word.
Milner’s initiative is allowing older scientists to forge new career paths, too. Last year, the astronomer Pete Worden left his position as director of NASA’s Ames Research Center in California’s Silicon Valley to “to pursue some long-held dreams in the private sector.” Today, those dreams were revealed, when Worden was announced as the new chairman of Milner’s Breakthrough Prize Foundation. “I do believe we are on the verge of a new era in public-private partnerships,” Worden said in an interview. “This is the reason I left NASA—to help bring this partnership to fruition.” It was his exposure to Milner and other risk-embracing high-tech entrepreneurs of Silicon Valley, Worden said, that had motivated his departure, as well as shifting priorities within the U.S. government.
“The opportunity for these projects to use significant time on the world’s best scientific instruments is occurring in part because of the limitations in government funding for these facilities,” Worden said, noting that flat or shrinking NASA and NSF budgets for astronomy have left the Parkes and Green Bank radio telescopes—as well as many other observatories—scrambling for new sources of financial support. Today’s announcement of Breakthrough Listen is likely only the first of several projects that could soon fill the astronomical void left by governments. “There are other potential initiatives under discussion,” Worden acknowledged. “All are related to the question of life in the universe.”
An Answer to Life’s Question
The revolutions in physics that laid bare the beautiful structure of the universe “can explain the light of stars, but not the lights that shine from planet Earth,” Hawking said. If life arose spontaneously on Earth, it must have done so an infinitude of times elsewhere in our seemingly infinite universe. “Somewhere in the cosmos, perhaps intelligent life may be watching these lights of ours, aware of what they mean,” Hawking said. “Or do our lights wander a lifeless cosmos—unseen beacons announcing that here, on one rock, the universe discovered its existence? Either way, there is no bigger question… A universe full of technological civilizations is a very different place from one with only us. Perhaps even different at astronomical scales. That makes astronomy's job to find out.”
But even though, as Marcy put it, the universe is chockfull of planets and “bulging at the seams” with ingredients for cellular biology, the chances of finding ET might be very low. “Who among us could doubt that basic single-celled life is common in the universe?” Marcy asked. “I would bet my house that among the nearest hundred star systems, single-celled organisms can be found and are flourishing. Or at least I’d bet Yuri’s house.”
The question of finding intelligent life, however, is a thornier one. Though life seems to have only taken 500 million years to arise on Earth, the move from simple bacteria to complex multicellular creatures took another 2.5 billion years, and technological intelligence has appeared on this planet only once. “It may be very rare,” Hawking said. “And when it does evolve, we only need to look in the mirror to know that it can be fragile and prone to self-destruction.”
Such “bottlenecks” between the origin of life, the evolution of intelligence, and the development and sustainment of a technological civilization could prove problematic not only for the search for ET, but also for our own future. If life proves common in the cosmos, but intelligence and technology are vanishingly rare, it may be that our own civilization does not have much time left upon the cosmic stage. Finding signs of other cosmic cultures, many SETI researchers believe, would be a way for us to know that it is possible for a global civilization to navigate its unstable technological adolescence.
“The stakes are very high, and that’s why I think we should never stop listening,” Milner said in an interview. “We should support this for ten, twenty, fifty, one hundred years—as long as it takes.”
Asked how likely it was that Breakthrough Listen would find evidence of alien civilizations within a decade, Drake conceded that “we don’t have sufficient knowledge to answer the question.” The key uncertainty circles back to his classic equation, particularly one variable, L, which represents the average longevity of a cosmic culture. If civilizations on average only exist in their loud, radio-transmitting high-technology phase for a few thousand years, they will be like flickering sparks among the stars, burning out before they can establish long-lasting beacons that can be seen across the cosmos. If, instead, they endure for longer durations, potentially millions or even billions of years, they could have populated much of the galaxy, and could be practically everywhere, waiting to be discovered and communed with—provided we know how to look for them.
Our own civilization has only had radio for about a century, and Drake noted our global culture is becoming less cosmically noisy due to technological innovations such as fiber-optic networks and digital television. But we shouldn’t necessarily extrapolate our experience to the stars.
“We are the beginners, the inexperienced ones,” Drake said. “We don’t know what we will become. And as a result we cannot use ourselves as an example for how long civilizations remain detectable… We have to explore in the dark and hope there are people like Yuri Milner to keep us going for however long it takes to succeed.”
see also:
No comments:
Post a Comment