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Are we alone in the universe? That’s the big question the Search for Extraterrestrial Intelligence (SETI) seeks to answer, and so far the answer appears to be yes. In the half-century since Frank Drake first used a radio telescope to begin searching for alien radio signals, there has been no message from ET—indeed no artificial radio traffic of any description.
SETI researchers argue that SETI has not been a failure, emphasizing that they have searched just a tiny fraction of the available space in the galaxy, and that the project is just getting started. To be sure, the computer revolution has enormously enhanced our ability to 1) search simultaneously over many different wavelengths, and 2) to filter out man-made signals, which theoretically increases the odds of a successful detection event.
But in the forthcoming book “The Eerie Silence” (Houghton Mifflin Harcourt), British-born physicist/cosmologist/astrobiologist Paul Davies—Director of the Beyond Center for Fundamental Concepts in Science, co-Director of the Cosmology Initiative (both at Arizona State University), and chairman of the SETI Post-Detection Taskgroup—argues that SETI scientists ought to broaden their search beyond “traditional SETI” (i.e., radio messages) to include a “search for general signatures of intelligence, wherever they may be imprinted in the physical universe. And that requires the resources of all the sciences, not just radio astronomy,” he writes.
I ventured to the Beyond Center in Tempe, Arizona, to meet with Davies and discuss the themes he explores in “The Eerie Silence.” In the following exchange—the first installment of a two-part Failure Interview—we covered issues like: What has SETI accomplished in 50 years? And what are some of the ways Davies suggests expanding the search?
In the meantime, the folks at the SETI Institute in Mountain View, California, continue to keep champagne on ice round-the-clock, in anticipation of the day scientists discover ET.
Why don’t we start by defining SETI?
Fifty years ago, in a famous pilot experiment [at the U.S. National Radio Astronomy Observatory in Green Bank, West Virginia], Frank Drake first used a radio telescope to see if any messages from an extraterrestrial civilization might be coming our way. Using a radio telescope isn’t the only way one can look for signs of intelligent life elsewhere in the universe, but it’s the most obvious way, because radio telescopes have the power to communicate across interstellar distances. So SETI, as it’s usually interpreted, is this radio telescope search.
What has been accomplished in 50 years?
The title of my book—“An Eerie Silence”—says it all. There has been no definitive message from any civilization or indication of any artificial radio traffic. There have been a few intriguing “don’t knows” [the “Wow” signal, a 72-second pulse detected on August 15, 1977, as well as a half-millisecond blip known as Lorimer’s pulse]—transient events that are difficult to evaluate after-the-fact. But nothing where one can say: If you point your radio telescope to a certain part of the sky you’ll pick up a bleep-bleep from what looks like an artificial source.
However, Drake’s pioneering experiment was done with steam age technology. Since then the computer revolution has enormously increased our ability to search simultaneously over many different wavelengths and to filter out man-made signals. It is no longer necessary for an operator to sit at the controls, steer a dish, and listen on a loudspeaker. It’s all done by computers and astronomers put their feet up.
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