Feeling Wobbly?

We all know that the earth spins on it's axis, an imaginary line that goes through the North and South Poles. What a lot of us may not know is that our planet "wobbles" a tiny bit on this axis, much like a spinning top that's slowing down. Just over a hundred years ago, scientists decided it was time to figure out just how much "wobble" was there.

Back in 1899, the International Geodetic Association established six small observatories around the world, all on the same latitude -- 38 degrees, 6 minutes North. Their assignment was to keep an eye on certain stars in the sky. Comparing information from different locations on the earth would help to make calculations about the latitude line and, thus, the wobble. I've always been intrigued that one of these observatories is here in my hometown of Gaithersburg, Maryland. The others were in Cincinnati, Ohio; Ukiah, California; Mizusawa, Japan; Charjui in Russian Turkestan; and Carloforte, Sardina, Italy. The Gaithersburg Latitude Observatory, a tiny wooden building, was in use from 1899 until 1982, with a break from 1915 until 1932 for economic reasons. In its working years, the roof would slide back to allow the telescope an open view of the sky. The observatory has been preserved as a National Historic Landmark.

Here it is today:




The small building sits in a field in a residential area surrounded by a fence looking like a tool shed. There are no signs or markings and I would imagine that few people know of its significance. You can read more about it here.