Are We Alone? Have We Always Been? How Do We Know?

A report from DARPA's Wait, What? conference

The Lick Observatory's Automated Planet Finder Will Help Out In The Search For Life

Laurie Hatch/Berkeley

ST. LOUIS — It's the loneliest question in the cosmos: Are we, creative and intelligent and flawed as we are, really all there is? Are we alone, and have we always been? Is there anybody else out there?

Leave it to the people of DARPA to think not only of answers, but of completely new ways to ask this question.

We might not be alone at all, but we probably won't find out by doing what we've been doing for the past few decades, said Lucianne Walkowicz, an astronomer at the Adler Planetarium in Chicago who works on the Kepler Space Telescope. Walkowicz spoke on a panel Friday on the last day of Wait, What? — a future technology forum sponsored by the Defense Advanced Research Projects Agency, the Pentagon's blue-sky wing.

"We haven't really looked," she said. "Astrobiology is a wonderful hot new thing in astronomy, but to say that you're looking for intelligent life in the universe is still actually a pretty fringe-y thing to do. We have this image that we've been listening for radio signals, that we've been searching for life in the universe, but actually we've been resource poor in that area."

We assume that other intelligent civilizations would broadcast radio signals like we do, she said — but we've been radio-loud for a short time, and we're actually getting quieter as our technology improves. And it's more complex than that anyway. We assume other intelligent civilizations would want to talk to us at all, or that they would even know to look. But what if other planets play host to hyper-intelligent space dolphins, who, in an attempt to evade dangerous stellar radiation, never left the sheltering waters of their world? They wouldn't even know there were other stars, Walkowicz said. Our interest in whether life is out there stems from our ability to see the stars, and recognize that we are a planet orbiting just one of them.

"There is a lot of leeway to understand what kinds of life may be out there, and what other biosignatures might we be looking for," she said. "Pressing that frontier forward, understanding what other signatures might be out there, is something we could potentially do experimentally."

wait-what-panel
Lucianne Walkowicz, left, describes new ways we might want to look for aliens at a DARPA future technology forum in St. Louis Sept. 11.Rebecca Boyle

Jeff Gore, a physicist at MIT, and Mark Norell, a paleontologist at the American Museum of Natural History, joined Walkowicz in chatting about the Fermi paradox, the Great Filter, and other cosmic condundrums. The Great Filter is the concept that something, which we can't understand yet, may prevent life from expanding into the universe; the Fermi paradox is the contradiction between the apparently great likelihood of finding alien life and the fact that we haven't.

It may be that we're not listening properly, as Walkowicz said. Or it may be that everyone else is just too far away, Gore suggested.

"Maybe it's just not practical to get to neighboring planets," he said.

Closer to home, many scientists think if life still exists elsewhere in our solar system, or if it ever did, there's a very good chance it was on Mars. So how should we treat the fourth planet? If it's barren, we might feel less hesitation to terraform or colonize it, Gore said. But Walkowicz said it should be protected if for no other reason than to help us understand life's possible origins.

"The way we should default to thinking about Mars is thinking about it as a nature preserve," she said. "It is our most reachable target for understanding the possible independent origin of life, or the independent evolution of life. ...If we were to go to Mars and terraform it, we lose the ability to answer the question of whether there is an independent origin of life."

"The way we should default to thinking about Mars is as a nature preserve."

Although nobody has found life elsewhere yet, there's not necessarily reason to despair, said Norell. Mass extinctions have wiped out vast majorities of species in our planet's 5-billion-year history, yet here we are.

"The one thing replicating DNA seems to have in common on this planet is it is very resilient. The rebound has been fast," he said, adding that this resilience may be true for alien worlds, too. "You would be pretty hard-pressed to go to a place on another planet and only find fossil life, and find everting on the entire planet totally exterminated."

Why talk about all these things at the Defense Department's research wing? Moderator Geoff Ling of DARPA said thinking about distant civilizations fits into the agency's mandate: "To go and think of things that others really don't."

"You won't find unless you explore," he said. "Biology is a very rich discipline, and is a place where, I would argue, surprise is waiting for us. If somebody is going to do it, let it be DARPA."