Now, I know cell phone camera are not the best for picture taking, but it was all I had. This place, Cow Canyon Saddle, is really not much to scream at, at least it wasn't during this visit. It was only 97 degrees there, as the elevation was a bit above the 109 degrees back at the house. The date was about three or four weeks ago.

So why post this photo? Because...

This spot is very near to the location of a very interesting historical event. It seems a definitive measurement of the speed of light was determined not too far away, way back in the earlier years of the 20th century...

In 1922-1927, Albert A. Michelson used Mt. Wilson to determine the speed of light more accurately than ever before. He did this by timing how long it took for a beam of light emitted at Mt. Wilson to return from a mirror at Lookout Mountain on the south ridge of Mt. Baldy. In order to compute the speed of light accurately, the distance between the two locations also had to be very accurately measured. The distance was measured by the U.S. Coast and Geodetic Survey by triangulation from a 40 km baseline in the L.A. Basin. This 22 mile distance between Mt. Wilson and Lookout Mountain was measured with an error of only 1/4", the most accurately surveyed distance in the world at the time.

The precise measurements yielded a speed of 186,285 miles per second (299,796 kilometres per second).

Above, Albert Einstein and Albert Michelson met at Mount Wilson in 1931, just before Michelson's death. From left to right are Milton Humason, Edwin Hubble, Charles St. John, Michelson, Einstein, W.W. Campbell and Walter S. Adams.

I understand some of the metal tubing once used for the experiment is now being utilized as drainage piping for Mount Wilson!...Mt. Wilson is not shown in photo (photo ref. UCLA dept. of Astronomy).

--Dan