But many people have trouble sensing that. The beep and the blip are both wired into the US Master Clock, so they really are simultaneous. Regardless, there’s a serious lesson behind the exercise. (Months later he informs me that, having gathered additional data, he’s rejected his theory about military people and scientists.) He appears satisfied with this, but I feel I’ve proved myself unfit for both science and soldiering. Because that sort of averages out, I tell Matsakis they seem simultaneous. I concentrate, but the beeps and blips seem to alternate, one arriving first, then another. Scientists, working in less perilous situations, hear the beep first. Military people generally see the blip first, he suggests, because they need to scan quickly for danger. And after years of informally testing visitors, Matsakis theorizes that each camp has its brains wired differently. Most visitors here are either fellow time geeks or officers interested in military applications. Without his department’s ultra-precise clocks, the Global Positioning System (GPS), cell phones, and the Internet would flounder, but few people even know the department exists. He runs the Time Service Department at the US Naval Observatory, which keeps official time for the country. Matsakis has a sly sense of humor: Jokes bubble up unexpectedly, and I can’t always tell when he’s making one-including now. Matsakis smiles and asks me to judge which comes first, the blip or the beep. 16 hours, 12 minutes, five seconds”- beep.

On the phone, an actor-Fred Covington, whose photograph hangs nearby-reads off the time. Meanwhile, I’m pressing a telephone to my ear, waiting for a beep.

Each device helps keep precise time, but out of all the dials, displays, and wires snaking about, I’m concentrating on a tiny screen that flashes once a second. I’m standing in a hallway near his office, facing a large window and looking into a room filled with multiple towers of electronics. Unlike most scientists, Demetrios Matsakis happily admits he has a “crackpot theory.” In fact, he’s eager to test it on me. Matsakis says he wasn’t always a time guy.

Timekeeper mastec