Theory of relativityMarch 20, 1916: Albert Einstein publishes his General Theory of Relativity (at right), redefining our understanding of the relationship of time and space.

March 20, 1974: In a closed hearing the U.S. Senate hears admissions of efforts to use cloud seeding as a weapon of war in Vietnam. "Operation Popeye" is revealed to the American public by investigative journalist Jack Anderson in 1971, but not admitted to by the Pentagon until this date. U.S. aircraft flew 2,600 missions over Laos, Cambodia and Vietnam from 1966 to 1972 in an effort to slow the North Vietnamese by heavy rain.

March 20, 2010: "The Hump," an upscale sushi restaurant at the Santa Monica, California Airport, announces on its website that it has closed. A week earlier, Federal officials indicted the restaurant's owners for serving whale meat as sushi. The Federal sting is prompted by an investigation by the producers of "The Cove", a documentary on dolphin slaughters in Japan.

March 20, 2012:  Maritime officials spot a “ghost ship” off Canada’s Queen Charlotte Islands.  The abandoned Japanese fishing boat was washed across the Pacific in the year since Japan’s massive earthquake and tsunami.

Photo: Lori Greig/Flickr

This feature is compiled by Peter Dykstra, an MNN contributor and publisher of Environmental Health News and The Daily Climate.