Forest Hills in Northwest Washington in Washington, District of Columbia — The American Northeast (Mid-Atlantic)

First Atomic Clock, 1948

IEEE Milestone

Photographed By Devry Becker Jones (CC0), December 17, 2017

1. First Atomic Clock, 1948 Marker

Inscription. The first atomic clock, developed near this site by Harold Lyons at the National Bureau of Standards, revolutionized timekeeping by using transitions of the ammonia molecule as its source of frequency. Far more accurate than previous clocks, atomic clocks quickly replaced the Earth's rotational rate as the reference for world time. Atomic clock accuracy made possible many new technologies, including Global Positioning System (GPS).

Erected 2017 by Institute of Electrical and Electronics Engineers.

Topics and series. This historical marker is listed in this topic list: Science & Medicine. In addition, it is included in the IEEE Milestones in Electrical Engineering and Computing series list. A significant historical year for this entry is 1948.

Location. 38° 56.524′ N, 77° 3.745′ W. Marker is in Northwest Washington in Washington, District of Columbia. It is in Forest Hills. Marker is at the intersection of Connecticut Avenue Northwest and Upton Street Northwest, on the right when traveling south on Connecticut Avenue Northwest. Touch for map. Marker is at or near this postal address: 4000 Connecticut Ave Northwest, Washington DC 20008, United States of America. Touch for directions.

Other nearby markers. At least 8 other markers are within walking distance of this marker. Connecticut Avenue Streetcars (about 500 feet away, measured in a direct line); Cultural Institutions (about 700 feet away); Science Has Its Traditions As Well As Its Frontiers

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(approx. 0.2 miles away); "Music of the Spheres" (approx. 0.2 miles away); Site of the National Bureau of Standards (approx. ¼ mile away); The Broadmoor (approx. 0.3 miles away); Landscape (approx. 0.3 miles away); Bungalow (approx. 0.3 miles away). Touch for a list and map of all markers in Northwest Washington.

Photographed By Devry Becker Jones (CC0), December 17, 2017

2. First Atomic Clock, 1948 Marker

Credits. This page was last revised on January 30, 2023. It was originally submitted on December 17, 2017, by Devry Becker Jones of Washington, District of Columbia. This page has been viewed 271 times since then and 17 times this year. Photos: 1, 2. submitted on December 17, 2017, by Devry Becker Jones of Washington, District of Columbia. • Bill Pfingsten was the editor who published this page.