At 5:30 AM 63 years ago today, J. Robert Oppenheimer’s brainchild was first tested at the Trinity site in what is now White Sands missile base in New Mexico. The device, code named “the gadget,” was Plutonium implosion based, because the Uranium version was a sure thing. Indeed, as President Truman decreed, the next 2 “tests” were over Hiroshima and Nagasaki (and ended WWII). The ball on the right illustrates the amount of Plutonium 239 needed for the bomb that destroyed Nagasaki.
MIT’s “Doc” Edgerton, the father of high speed photography, used his Rapatronic cameras (note the plural – one shot per camera!) to capture the event at microsecond intervals with exposures as short as 10 nanoseconds. The cameras were based on a sandwich of 2 polarized plates at 90 degrees to each other – blocking 100% of the light; with a filling of a cell that could polarize light at 45 degrees when energized. Due to the strange nature of light polarization, adding a 45 degree filter between two 90 degree filters actually lets 50% of the light through. Go figure!
They probably explain it well at the Exploratorium, the best science museum in the country, founded by Oppenheimer’s brother, Frank. Go read Lawrence and Oppenheimer by Nuel Pharr Davis for the Trinity backstory. It is a great read.
P.S. A photo of the initial tenth of a microsecond of the Trinity blast has been on display by Doc Edgerton’s old office in MIT forever. But, until recently, for security reasons(?), unlike the milk drop crown, it has had no label. If you go see it, it is unlikely you’d mistake it for a bullet through a balloon!