Star Talk Without Oprah
This time, if E.T. phones, we’ll be listening in. On Columbus Day, the National Aeronautics and Space Administration launched a $100 million project to search for signs that there are civilizations in outer space. The 10-year project was launched when two giant radio telescopes—one, the Goldstone Deep Space Communications Complex in the Mojave Desert, the other in Arecibo, Puerto Rico—began to scan the skies for electromagnetic signals. “We’ve been asking whether other life exists in the universe for as long as there has been recorded history, “says Dr. Jill Tarter, 48, project scientist at NASA’s Ames Research Center in Mountain View, Calif, who will direct the search at the Arecibo complex. “We’ve asked the priests and philosophers, our sources of wisdom in the past. Now the thing to do is to ask the engineers and scientists to see if they can get verifiable, concrete evidence.”
Tarter herself provided some answers to Miami bureau chief Meg Grant.
Do you really think there are intelligent beings out there?
When I was a kid, I spent time in the Florida Keys. At night there aren’t any lights, so you can see all the stars. It’s just impossible to experience that without thinking there have to be other worlds like our own.
We’ve looked for those worlds before. What’s different about the new search?
In 1960, Frank Drake [an astronomer at the University of California at Santa Cruz] searched two stars for a couple of hundred hours. Neither that search nor the 60 or so since have been comprehensive. This is the first time that we’ve said, “OK, what does it take to do a systematic, unbiased, comprehensive search?” This is what we are attempting now, and we gathered more information in the first few minutes than has been done in the past 32 years.
How will the project go about such a huge task?
We’re pointing the radio telescope to track a particular star in the sky for somewhere between 5 minutes to 15 minutes at a particular frequency. So far our list contains about 1,000 sunlike stars, from 4 to 100 light-years away, that might be orbited by life-supporting planets.
We’re also doing an all-sky survey using smaller telescopes that can move faster, where we look everywhere without spending very much time in any one direction or at any one frequency.
Why are we listening—rather than looking—for signs of intelligent life?
We’re listening because electromagnetic signals travel at the speed of light, and this is the fastest you can go. Because of the huge distances involved, we don’t now have the technology—and may never have it—to travel by spacecraft. We can envision the technology to look for signs of life on distant planets, but we don’t yet have it either.
And where are we listening?
At microwave frequencies from about 1,000 to 10,000 megahertz. That is the baud in which the background noise is the lowest, where from the surface of our planet we have the quietest window on the universe.
Even so, the earth, with its airport radar, garage-door openers and cellular phones, for example, creates a lot of microwave noise. Soon we may not be able to hear above our own din.
So why don’t we send the signals instead of waiting to receive one from someone else?
Inadvertently, we do. Our televisions and radios leak microwave signals, for instance, so it someone were listening, they might be picking up I Love Lucy right now. But suppose we sent deliberate beacons to the closest star we have targeted, which is four light-years away. Assuming we got an immediate answer, we would still have to wait at least eight years for it. Listening could be more of an instant-gratification scheme.
So you’re looking for a beacon rather than another planet’s prime-time TV series?
Either one. We’ll find the leakage if it’s strong enough, but I suspect there are intentional beacons out there. Given the distribution of stars and what I think is a very large probability that life and technologies have arisen elsewhere, the odds are that somewhere two inhabited planets are going to be relatively close to each other, and two technological civilizations are going to stumble across one another somewhere in the 10-billion-year history of the galaxy. They’ll start transmitting, and we’ll pick up on that. I can’t prove it; it just seems statistically likely.
If so, why haven’t ire already been discovered by a civilization from outer space?
We might have been. Another civilization may well have heard us, if they’re within 52 light-years, because our powerful leakage started back in 1940 with the first commercial television broadcast. But we might not know that they’ve heard us because their response hasn’t gotten here or we haven’t been listening in the right place to receive it.
Have you heard anything yet?
No. We’ve heard the island of Puerto Rico but so far no candidate signals that we’ve needed to start up our confirmation program for.
How soon might you?
You just don’t know what if might take to be successful. So most of us take our reward from getting this started, from solving the technological challenges that a few years ago seemed so impossible.
What happens if yon do hear something?
As part of our confirmation system, we will contact the Owens Valley Radio Observatory in Southern California, which is on standby, and ask them if they can track it. If they can, and we continue to track it long enough—say, hall an hour—to be sure that the signal is coming from a distant star and not a nearby transmitter, then we’re going to call a press conference.
Will you reply to the message?
We’ve said as a project that we won’t reply until there’s a global consensus to do so.
And if you don ‘I hear anything, what will you say to the critics who charge that Hi is project is a waste?
The pioneers, people like Frank Drake, had to risk the ridicule of people laughing at them. They had to make a real leap of faith. As for our project, we could discover some new astrophysics—the sky survey will be doing a lot of radio astronomy. And the technology we’ve developed has applications elsewhere.