It’s a fallish day in the Allegheny Mountains of West Virginia, the rural home of Green Bank Observatory and the world’s largest fully steerable telescope. Rippled clouds hang low over the site’s hulking 100-meter radio dish, itself undergirded and overhung by bright white scaffolding. The browning leaves are nearly gone. And the visitor center director, Sherry McCarty, has agreed to give me the astronomy center’s new SETI tour ($40, reservations required).
McCarty leads us toward a Jeep Liberty—diesel, so spark plugs won’t create radio waves that interfere with the telescope’s observations—and hands me a hard hat. Learning about the history of alien hunting is risky business, after all. Soon, we’re driving toward the US GOVERNMENT PRIVATE PROPERTY gate, beyond which radio-blasting cell phones are totally, 100 percent prohibited. I check my back pocket to make sure I left my phone behind.
Highlighting SETI history is kind of a departure for Green Bank, which has tried, if not to distance itself from extraterrestrial excitation, then to emphasize its work in more traditional radio astronomy: gas clouds, galaxies, supernova remnants, black holes, and other staid stuff.
When I taught students here between 2010 and 2012, I sometimes led the regular site tours. People would often ask me, “So … have you found aliens yet?” Each time, I’d let out a silent scream. Of course that would have come first in my spiel and also in all other conversations ever—and besides, the observatory didn’t even really do SETI work at the time. Like me, most comms people at the observatory spoke of SETI as more of a comma than an exclamation point in Green Bank’s history.
But that changed—quickly, dramatically—in 2016, when the billionaire-backed Breakthrough Listen project bought a bunch of time on the 100-meter Green Bank Telescope. Now, a significant fraction of the observatory’s funding and sky-scanning time do go toward looking for extraterrestrial intelligence. “That was the reason for the tour,” says McCarty. “We could finally say we were looking.”
Of course, that means Green Bank has to abandon some astronomical objects of interest—in favor of alien-hunting.
Most of Green Bank’s science projects have, historically, happened through a kind of democratic process. Under a National Science Foundation policy called “open skies,” anyone can submit a proposal outlining what they’d like to do with the flagship telescope. A committee ranks those ideas according to scientific merit, doling out telescope time starting at the top of the list.