Somewhere out there — buried under ice in our solar system, waiting on a deep-Milky Way exoplanet, on radiation en route from the Great Beyond — lies the answer to the question, “Are we alone?”
Jill Tarter, chair of Search for Extra Terrestrial Intelligence Research at the SETI Institute in California, is in pursuit of an answer. In a talk titled “Thinking Out Loud: Deciphering Mysteries of Our World and Beyond,” she offered her case as to why and how the cosmos will provide the answer in the affirmative and in this century.
Biologists have claimed that while the 20th century was the century of physics, the 21st will be the century of biology, Tarter said. “They were right, but they were also too tentative,” she said. “I think many of you in this room are going to live to see the first evidence of life beyond earth.”
Tarter, whose accolades include placement among the Time 100 Most Influential People in 2004 and portrayal by Jodie Foster in the sci-fi drama “Contact,” is more suited than most to make that claim. In his introduction to her lecture, Christopher Rose, professor of engineering and associate dean of the faculty for special initiatives, called her the “doyenne,” or the most respected woman, of SETI.
She opened the lecture by providing the audience with necessary context, tracing humanity back through the 2.4 billion years during which Earth’s atmosphere has existed, the five billion years of our solar system’s lifetime and a supernova explosion billions of years before that. That, Tarter said, is where the story must begin.
“Our context today is that we understand that we are in a fragile island of life within a universe of possibility,” she said. She attributed this understanding to two 20th-century game-changers: the discovery of extremophiles, or life forms that exist in inhospitable conditions, and of exoplanets, or planets beyond our solar system.
“There may be a lot more habitable real estate out there than we once appreciated,” she said, showing images of Earth-dwelling organisms — gray lines, green swirls, red spheres that were all actually alive — that challenge our conceptions of what life must look like.
Tarter took the audience on a brief tour of the solar system, starting on Mars, where the Curiosity Rover just proved the existence of liquid water, and moving to Jupiter and Saturn’s moons, where ice volcanoes could offer a “cosmic free lunch” to probes looking to detect water samples without having to dig into the planet, she said. Then she moved beyond, into the world of exoplanets that the National Aeronautics and Space Association’s Kepler spacecraft is discovering.
“It is absolutely amazing to stand here and tell you when I was a grad student, we had nine planets and then lost one and didn’t know planets outside our solar system existed,” she said. “We can now say with statistical certainty there are more planets than stars in the Milky Way.”
These discoveries of exoplanets and the stars around which they revolve — like KIC 8462852, which Tarter called the “WTF Star” thanks to its unusual properties — have significant implications. With technologies that enable astrobiologists to determine the chemical composition of stars and physicists to detect radio waves potentially emitted by intelligent civilizations, SETI searchers have a growing toolkit to draw from.
The raw products of this toolkit — data collected by telescopes all around the world — are increasingly available to science enthusiasts, Tarter said. “SETI@Home hit the Internet, and millions of people started processing data. It is the largest computer on the planet; I think we are really going to benefit from energy and interest of the community.”
In these terms, the task of searching the cosmos for life seems straightforward. But then Tarter would again invoke the scale at hand.
“The cosmic haystack is huge — it’s nine-dimensional,” she said. Beyond space — three dimensions — and one dimension of time, the parameters get fuzzy: two senses of polarization, one dimension of frequency, one modulation scheme. And then there’s the matter of our measuring devices, which Tarter said are likely not sensitive enough.
Of course, any discussion of SETI will inevitably involve unknown variables: the probability that a planet has developed life, developed communication and lasted long enough to beam signals to Earth are all currently the stuff of guesswork, Tarter said.
But the packed room in the Building for Environmental Research and Teaching was less interested in talking about the daunting variables or the possibility of extraterrestrial life than about the implications of its discovery. If we receive a signal, how do we respond? How will Earth react? Do we venture into the universe with a whimper, or with a bang?
Stephen Hawking famously advocated the former, Tarter said, while she takes the opposite view. “These people will have managed to survive because they have evolved beyond aggressive tendencies,” she said. “You cannot get to be old unless you figure out how to be nice first: how to husband your planet, how to work together, how to have a long future.”
Jim Head, professor of geological sciences, wanted to know how individuals invested in SETI can get the public to know that “cosmic perspective is a necessity.”
“I don’t know how we can reverse that other than going and talking to people,” Tarter said. “My job description is to convince you that you’re an earthling. If we can internalize that perspective, there is a lot we can do in the future in terms of technological challenges that do not respect national boundaries.”
That’s why SETI is so critical, Tarter said. Even if the variables remain unknown and the search yet unfruitful, it “trivializes the differences among humans that we find so difficult to deal with today.”
Alisa Pugacheva, visiting Brown for A Day on College Hill, said she was inspired by Tarter to pursue science years ago, and came to the lecture to thank her. The discussion that included science topics from gravitational waves to dark matter to “WTF Stars,” then, was extra.
“I feel like my brain is exploding,” Pugacheva said. “It’s just awesome.”