Greetings family, friends and neighbors. The earth doesn't rotate exactly on it's axis but has a slight "wobble", a phenomenon detected by six international locations including one in a small Northern California town. Today's Historic Snippet is about the Ukiah Latitude Observatory....Bill
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IT’S A WOBBLING WORLD
As early as 1765 Leonhard Euler theorized that the earth didn’t rotate on it’s axis in a constant precise manner. Dubbed the “Chandler Wobble” by businessman turned astronomer Seth Carlo Chandler in 1891, understanding polar motion was critical in the determination of latitudes and in 1895 the International Geodetic Association created the International Latitude Service to enlist dozens of astronomers worldwide to track and document the phenomenon. With central offices in Potsdam, Germany a system of six observatories were established around the earth at 39 degrees 8 minutes north latitude to perform uniform data collection and analysis. The observatories were located in Italy, Uzbekistan, Japan, and three locations in the United States; Gaithersburg, Maryland, Cincinnati, Ohio, and 140 miles North of San Francisco in Ukiah, California. Beginning in 1899, every night for nearly a century when viewing was possible, astronomers in each of the six observatories studied the same six pairs of stars in a preset schedule and later compared the measurements of the twelve stars with the other stations. Data collected on the constant shifting of the earth’s axis from Ukiah and the other five observatories through the years has been invaluable in the study of polar motion, climatology and
satellite tracking. With advances in computer technology and satellite observation all the stations became obsolete and the Ukiah Latitude Observatory was closed in 1982. The property containing the modest twelve foot square international landmark and three accompanying historic buildings has been restored and was developed into a city park in 2014.
The groundbreaking primitive GPS system with deep ties to Ukiah, California determined that the earth’s axis in fact drifts slightly around the poles, as much as thirty seven feet, and fostered international cooperation during two world wars and times of conflict.
It’s a Wobbling World after all
-Bill 3/25
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