It’s About Time…

Ever since I was in high school I’ve wanted to see the Atomic Clock.  I can’t always remember my family member’s birthdates but I knew from memory that if I called 303-499-7111 I’d hear a ticking sound and every minute a voice would declare the precise “Coordinated Universal Time”.  Go ahead, try it…  Now that we’re in the Internet age you can also find the exact time at  And just as a heads up, TV network evening newscasts (ABC, NBC, CBS) always start at precisely 630pm straight up.

This is the NIST-F1 Cesium Fountain Atomic Clock located at the National Institute of Standards and Technology (NIST) in Boulder, Colorado.


(Photo credit:

Well, I’m taking their word for it that this is it.  When I showed up at the sprawling campus of the a huge US Department of Commerce facility where various labs are located I turned where my GPS told me to turn and ended up the parking lot of a nearby business.  I went inside to ask if I should move my car (their parking lot wasn’t very crowded) or leave it for about a half hour.  The receptionist said it was fine where it was.  I walked over to what appeared the main building.  It was locked, and it appeared that security was tight.  Two guys were apparently coming back from lunch and directed me to the nearby Visitor Center, maybe a quarter mile away.

The Visitor Center consisted of three large security guards seated behind computer screens.  One of them looked up the number for the Public Relations Officer for the department which would involve the Atomic Clock.  Apparently tours can be arranged in advance in some cases but they frown on walk-in’s.  My phone wouldn’t work (5 bars but no connection.  It might have been blocked so as not to affect the labs?).  I really wasn’t expecting to get very far so I just gave up.






This is an aerial photograph of the entire facility.  The part I saw is in the extreme lower right of the picture.


The current clock was designed by Steve Jefferts and Dawn Meekhof of the Time and Frequency Division of the NIST Physical Measurement Laboratory (try to fit all that on a business card!).  It won’t gain or lose a second for 60 million years, and they’re still improving it!  It is the main source for accurate time in the United States.  The Defense Department also relies on a similar clock at the US Naval Observatory in Washington DC which has a backup at Schriever Air Force Base outside Colorado Springs, Colorado.  Schriever is also the home of GPS (see the blog post dated August 24, 2017).


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