Movies of Cold War Bomb Tests Hold Nuclear Secrets (wired.com)

An anonymous reader writes: Nuclear weapons specialists are limited in their research today. Prudence and international treaties prevent them from setting off any nuclear weapons, so they have to run tests through other means and interpret the results. But this wasn't always the case. In the '50s and '60s, the U.S. government performed a huge number of nuclear weapons tests, and filmed most of them. As happened with a lot of film from that time, most laid untouched in storage facilities until people generally forgot about them. But physicist Greg Spriggs recently realized they could be a trove of useful information, so he started tracking them down, eventually locating thousands of them. His team has started scanning and analyzing them. They've finished about 3,000 so far, with more than half yet to go. "Now, of course, scientists have computer programs that can analyze every single pixel in a frame over hundreds of frames. What might have taken days by hand takes only minutes. With computer analysis, Spriggs is pinpointing more precise yields. Computer models then use yield to estimate the damage from a bomb in different situations."

Comments

Re:Secrets

[Dins]

It is done by tracking the speed and size of the shockwave captured in the films, which was originally done by hand. There was up to 20% variation in the results of the measurements made by hand. They are now using computer software to perform the optical per-frame analysis of the shockwaves, and the result is more accurate measurements of the weapons' yield.

Fun fact: The vertical smoke trails present in many nuclear test films are there so they can "see" the shockwave on film as it propogates and affects the smoke trails. Right before detonation a row of rockets are launched vertically to create the smoke trails. I only mention it as for the longest time I wondered what these weird lines were from, and thought they might be some weird effect of the bomb or something. So I looked it up and learned the above.

Re:Didn't the US reject the comprehensive treaty?

[tnk1]

Yes, it isn't law. It doesn't prevent us from more or less complying with it unilaterally, it's just that we aren't binding ourselves to it. That gives everyone else a lot less peace of mind about it, but the US often has its own reasons for basically following the gist of treaties it doesn't ratify, so it usually works out. Usually.

Re:Secrets

[hey!]

The Comprehensive Test Ban Treaty was adopted by the UN General Assembly in 1996, but won't come into force until 44 specific nations with nuclear technology capabilities have ratified the treaty. At present there are eight nations on the list who have not ratified the treaty, including the United States. The US, however, is a signatory to the treaty, and has not conducted a nuclear test since 1992.

So the US abides by the CTBT as a matter of policy, even though the treaty is not in force, and the Obama administration has in the past indicated that it wants to ratify the treaty, although that won't happen with this Senate.

The reason it's smart policy to promote the adoption of the CTBT is that it would discourage nuclear proliferation, and we don't need to perform testing. We already have enough data from half a century of active testing to ensure our bombs go boom.