The Atomic Clock and International Time 

Chip scale atomic clock photo by the National Institute of Standards and Technology.

There are many devices that have been used to measure time since the concept of time began. From the position of the sun to using the ingenious sun dial to nanosecond accurate clocks today, time telling has evolved over the ages. In the history of the clock, there have been sun dials, hour glasses, water clocks, pendulum clocks and mechanical clocks. Continue reading

AstroBlog Follow Friday & Weekly Stumbles For 2012-07-13 

Solar Flare: Another M-Class Flare from Sunspot 1515

Active Region 1515 has now spit out 12 M-class flares since July 3. Early in the morning of July 5, 2012 there was an M6.1 flare. It peaked at 7:44 AM EDT. This caused a moderate — classified as R2 on the National Oceanic and Atmospheric Administration’s space weather scale — radio blackout that has since subsided. Continue reading

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