It sits atop a pine-studded hill, 25 miles west and far from the bright lights of Boston, tucked into a stand of tall trees beyond the horse farms and the apple orchards of north Worcester County.
Each night when the skies are clear, a 4-ton retractable roof on an otherwise nondescript wooden structure rolls away, and machinery inside whirs to life to renew its methodical search for what would be the most stunning discovery since the dawn of man.
With a 72-inch optical telescope, Harvard University scientists are searching for signals from advanced and distant civilizations, each second processing a quantity of data equal to the text of all books now in print.
Are we alone? Fat chance, they say.
"They can't be dumber than we are because if they are dumber, they wouldn't be able to send us signals,'' Paul Horowitz, a Harvard research professor of physics, told me in his office just off Harvard Yard. "If we make contact with anybody, they're going to blow us away with their smartitude.''
Horowitz is an energetic, impish, self-deprecating man who dashes around his third-floor office, pulling books from shelves that stretch to a high ceiling or scooting over to computer monitors to dole out morsels of celestial knowledge.
While he insists that he's a "boring nerd,'' the guy has got to be the most popular cocktail party guest in his ZIP code. Maybe his time zone.
Did you know that there are more stars in the universe than grains of sand on all the beaches? And there are tens of billions of Earth-like planets in our galaxy alone?
Horowitz is a pioneer in the search for extraterrestrial intelligence. His work has drawn plaudits and snickers, and he's keenly aware of both.
There are nonbelievers everywhere. But Horowitz has been working to prove then wrong almost since his grad school roommate took a course taught by legendary astronomer Carl Sagan, with whom Horowitz would later work.
"We're all hoping someone makes the discovery before we all croak,'' he said. "That's what keeps me going, I suppose.''
The optical telescope on the hill at the Oak Ridge Observatory in Harvard is seeking laser signals from other worlds, making a trillion measurements of the heavens every second. Horowitz used to search for radio transmissions, but switched for surprisingly easy-to-understand reasons: "We got tired of radio transmissions because we weren't finding anything.''
There were moments of pulse-racing possible discoveries, but nothing that survived scrutiny. In other words, no contact.
Horowitz has allowed himself to imagine what would happen when that day arrives. And he has allowed himself to think what the real ET might look like. Not like us. Maybe silicon, a post-biological being. Not upright, bipedal hominoids. "Get rid of your biological chauvinism,'' he said. "Stop thinking about it that way. There's no reason to believe they'll look like us.''
For now, he watches and waits.
"Someone once told me that I've got one chance in a million to become the most famous person ever,'' the professor said. "Maybe it's a little less. But it's guaranteed to be the most famous discovery ever.''
Who hasn't imagined that?
When I was a kid in the early 1960s, my dad would pile us all into the back of our battered station wagon and we'd head for a long-gone drive-in. The most memorable movie of those summer screenings was the 1951 classic, "The Day the Earth Stood Still,'' starring Michael Rennie as the alien.
There is a signature line from that movie that my brother and I still toss at each other from time to time for no reason at all. And I wanted to use it with Horowitz.
I struggled to figure out how without seeming silly. Then this learned man of physics invoked it for me unbidden: "Klaatu barada nikto.''
Google it. Like Paul Horowitz, it's kind of famous — a set of words from worlds unknown like those that he's been waiting most of his life to hear.
Thomas Farragher is a Globe columnist. He can be reached at email@example.com.