about a million degree above absolute zero and then we launch them. all that information which varies by nanna no seconds is then fed here. this is the nation s master clock. all of those, all of those 100 clocks this is the national clock, the master clock for the department of defense. next door, the time transfer room sends the time out to the nation and the world. even that phone number you call to get the time. at the tone, eastern daylight time, 15:50 exactly. he headed the time service department for 16 years, starting in 1997. he is now the chief scientist. and he says the job comes with a certain amount of, well, time-pressure. there have been three times when the master clock itself has broken, always when i ve been on an airport. when people leave working for a time service, it doesn t take long, maybe a week or two when