National Atomic Clock Timekeeper

Odd Jobs, On the Road, People
on January 3, 2012
Steve Groer Judah Levine maintains the nation's official civilian time for the National Institute of Standards and Technology.

About 5 billion times a day, Judah Levine helps answer the question, “What time is it?” And amazingly, he’s always correct-—down to a nanosecond-—though he doesn’t wear a watch.

A physicist for the National Institute of Standards and Technology (NIST) in Boulder, Colo., Levine maintains the nation’s official civilian time and supervises services that automatically disseminate the time to clocks, computers and cell phones from Main Street to Wall Street.

“We get about 50,000 requests for time every second of every day,” says Levine, 71, who helped build a series of atomic clocks during the 1970s and developed one of the most accurate time-keeping systems in the world.

Levine joined NIST in 1969 after conducting postdoctoral research for the agency, and he’s spent his entire career telling time with atoms and computers. “I’ve always been interested in precision and accurate measurements,” the New York City native says.

In 1988, Levine introduced the Automated Computer Time Service, which synchronizes computer clocks with the official time using telephone lines. Five years later he launched the Internet Time Service, which syncs networked computers. “You connect to the Internet, and you get this free service,” he says.

By 7 a.m. each weekday, according to the radio pager in his pocket, Levine is in his office on the University of Colorado campus. His first order of business is to use his laptop computer to check the atomic clocks in the nearby NIST laboratory.

“Ideally, everything is working properly and there’s nothing to do,” he says. “Checking can take an hour to all day. Fixing a problem takes as long as it takes.”

Levine rarely has much spare time. Working alongside a team of scientists and engineers in NIST’s Time and Frequency Division, he spends about 70 hours a week repairing computer hardware and software, designing upgrades to the time services, answering time-related questions via email and telephone, and calibrating clocks for other government labs and private industries, including clock-manufacturing companies.

Daily, he heads to the NIST time labs and monitors the clocks in person. Twenty-four hydrogen and cesium atom clocks are housed in temperature-controlled vaults that resemble oversize refrigerators. Every 12 minutes, computers average the times from the clocks to produce a single reading, which is the official time.

Each week, Levine also monitors five other atomic clocks stationed at WWVB near Fort Collins, Colo. The NIST radio station broadcasts the official time—by the second and minute—and transmits a signal to millions of wall clocks, clock radios and wristwatches across North America.

“This enabling technology makes possible all sorts of things,” Levine says about computerized time. “In the financial world, if you buy a stock and the price keeps going up and down, you want to be sure what time that trade was executed. If two people are asking for reservations on a flight and there’s only one seat, then you need to know who asked first.”

Precise time and frequency measurements are needed for electric power grids, seismic monitors, and navigational and telecommunications systems. “Phone companies require frequency synchronization, so that a cell phone call will work across all different phone companies,” Levine says.

Levine also serves as an expert witness in court cases when time-stamped cell phone calls, surveillance cameras and stock market transactions are presented as evidence.

The nation’s timekeeper, however, sometimes loses track of his own time, according to Trudi Peppler, a computer specialist who has worked with Levine for 31 years.

“Judah works closer to 80 hours a week,” says Peppler, 49. “He’s very dedicated and hard-working. There’s nobody else in the country who knows more about our time scale than he does.”