THE THUMB WAR

"Vault Boy" poster at video game store

A common rule of thumb (quite literally) in the atomic age involves the calculation of the intensity of a nuclear bomb blast. Specifically, if you stick your arm all of the way out and can cover the image of the mushroom cloud with your thumb, you will be far away from the blast that the heat, shock wave, and fallout, when they eventually arrive, will be too weak to affect you. At least, that is what the theory says.

The rule is also supposed to apply to everyone regardless of body size. For those persons with smaller thumbs, they will also have shorter arms, which means that the thumb will be closer to the eye and its image will effectively cover about the same amount of area as perceived by a larger individual.

The thumb test has been incorporated within the Fallout series of electronic role-playing games featuring a post-apocalyptic society ravaged by nuclear conflict. "Vault Boy," the mascot of the game series (as well as that of "Vault Tec," a corporate entity featured in the games), is often depicted in thumb-up configuration gazing at atomic explosions.

Is there any validity to the rule? The possibility at least exists that it may serve as a rough test for the effect of the shock wave and the heat, although there would still be several variables, such as the size of the bomb, the altitude of detonation, the presence of buildings, and the topography of the area in general. Fallout can travel huge distances over time, and the rule is probably not at all effective for that purpose.

Personally speaking, if I were ever to see a fresh atomic explosion, I will not be standing out in the open gawking at the blast with an upright opposable digit waiting to be shredded by the potential shock wave. I will be rushing instead to get my loved ones behind a concrete wall in the basement, irregardless* of whether or not I can obscure the mushroom cloud with my thumb.

As "irregardless" has been in use for over a century and is found in most dictionaries, it is in fact a word, and it means the same thing as "regardless," just as "inflammable" means the same as "flammable." So get over it.

View image | gettyimages.com

Thanks (or should I say "thumbs up?") to Michael Green for the heads up on this factoid!