> Nuclear detonations show two characteristic light pulses. This double-pulse phenomenon is evident in the video of the “Harlem event,” a 1.2 megaton test that took place 13,645 feet above the Christmas Island area of the Pacific on June 12, 1962. The first pulse peaks almost immediately as the shockwave first forms (0:09 in the video). The brightness then decreases as the superheated air, which is opaque when heated to above 3,300 degrees Kelvin -- or 5,480.33 degrees Fahrenheit -- shields the light from inside the fireball (0:10 in the video). As the shockwave cools to below 3,300 Kelvin, the air becomes transparent and the hot gasses begin to show through, creating the second pulse (0:21 in the video).<p>This is so interesting. I've always noticed the iconic double flashing in nuclear detonations but I never knew why it happened.<p>> Software developed by LLNL computer scientist Jason Bender scans each frame of the films to automate the measurement process. Bender’s software notes the timestamp of both pulses of light, as well as the darkest frame between them. With this data, Spriggs can calculate the test’s yield.<p>Sounds like a fun project, writing algorithms to parse 50yr old classified films of nuclear detonations.
I am concerned that uploading the videos to YouTube isn't archiving. I realize they perhaps maintain their own backups of the digitized versions, but one cannot otherwise preserve them by sharing them with the world via YouTube.
Thinking of nuclear weapons, why is there too little mainstream political support for unilateral nuclear disarmament in western democracies. I do not think there is much necessity for atleast UK and France to keep and further develop nuclear deterrence. For now atleast in UK the major reason for maintenance and renewal of nuclear weapons and their delivery platform seems to be that, they needs to be done lest thousands lose their jobs, which is a reason so out of 'Yes, Prime Minister'.
"When he dug in to find out why there was a discrepancy, he discovered that the manual measurements made in the '50s and '60s were off, in some cases by 20 percent to 30 percent."<p>I'd heard that during the war the US exaggerated the power of nuclear weapons but this is the first time I've seen evidence to substantiate the claim. Was the data high or low? I perused the article twice and couldn't find clarification.
> Measurements taken in the '50s and '60s focused on the rate of growth of the fireball. These measurements were done manually by projecting each frame onto a grid, with an analyst jotting down the eyeballed measurement before the projector’s heat began to melt the frame.<p>What?
There's a guy that's digitizing them to get more accurate classifications as to the strength of the blasts and the sad thing is he's finding that some of the canisters are full of basically dust from some of the film disintegrating. :(