Spring forward. Daylight saving time begins early Sunday morning at 2am. Sunset time on Sunday will be 6:46pm. Yay.
The U. S. Naval Observatory Master Clock is the most accurate timepiece in the world. (This is not that clock.)
In the case of GPS, the Master Clock helps carefully measure the travel time of electromagnetic signals between satellites and Earth. Since time is space and space is time, you can’t know one without measuring the other: When you fire up Google Maps to determine your location “an accuracy of 10 nanoseconds (10 one-billionths of a second) corresponds to a position accuracy of 10 feet,” according to the Naval Observatory.
The Naval Observatory is one of the oldest scientific agencies in the United States; its primary mission is producing Positioning, Navigation and Timing (PNT) for the United States Navy and the United States Department of Defense. Aside from its scientific mission, a house located within the Naval Observatory complex serves as the official residence of the Vice President of the United States.
This photo was taken recently at the Ladd Observatory, the public astronomical observatory of the Brown University Department of Physics. The observatory is open to the public on Tuesday nights, weather permitting.
The clock face was lying on a counter.