do todays nuclear weapons really poison the spot on earth where they hit for generations? if so, why did the bombs dropped on japan not do it? nagasaki and hiroshima are still large cities today. do we still use the same type of bombs that we used on japan?
uhmm…
i thought nagasaki and hiroshima were still just scarred-earth atomic wastelands today…
Today’s thermonuclear bombs are just a wee bit bit bigger than those of 1945.
Hiroshima and Nagasaki are thriving, industrial cities. Although the surviving citizenry fled after the attack, fearing the earth was poisoned, plants began regrowing almost immediately. The cities were reoccupied within 3 months at first by the citizens themselves, and later with the help of the US Government who built wooden barracks for the survivors.
As has already been mentioned, the nuclear weapons in today’s arsenal yield orders of magnitude more energy than the weapons used in WWII. The Hiroshima and Nagasaki weapons were in the 10-20 kiloton range. A small, modern 10 megaton warhead yields 1,000 times as much energy.
As I understand it, even though an H-bomb puts out vastly more energy than Fat Man or Little Boy, they are comparatively “cleaner”, radiation wise, since the atomic portion of it is only enough to start the hydrogen fusion. Over the years, scientists have shrunk that “initiator” way, way down. So, getting crisped by an h-bomb is comparatively organic.
No doubt, a great comfort to all concerned.
Actually most modern U.S. strategic nuclear warheads have yields of no more than a few hundred kilotons. The theory is that rather than building ever more powerful bombs, you build more accurate missiles and other delivery systems instead. A warhead which yields “only” a few hundred kilotons will destroy even hardened missile silos or command bunkers if you can drop it precisely on the target. Note that the monster 9-megaton B-53 (an aircraft delivered weapon) has been supplanted by the more technically sophisticated B-61, which has a maximum yield of 340 kilotons, but which in some models has a hardened steel case that can bury itself underground before detonating to crush “hardened” targets. (Note that such a ground burst would be very “dirty” in terms of fallout.) Modern American ICBM and submarine launched ballistic missile designs similarly stress accurate delivery over piling on the megatons.
MEBuckner is right about the strategic nature of modern nuclear weapons and the yield of individual warheads. I don’t know what I was thinking! My number are off by a factor of 10, even for a mirv’d missile. So, let’s try again. A modern 1 megaton missile, like the Minuteman III (containing three warheads) yields about 100 times as much energy.
Check out HowStuffWorks.com for how nukes work. Interestingly, a fusion bomb is about 10 percent efficient, leaving most of the fuel unused, and radioactive, poisoning us. (Plutonium is very, very toxic for a long time.) When the bombs are airburst, the radioation and fallout disperses quicker, but when they are ground burst, they dirty up the soil. The bombs dropped on Nagasaki and Hiroshima were (if my memory serves me correctly) exploded by altimeter at about 2000 feet, giving us an airburst. I suspect if you want lots of radiation in soil the test zone in Nevada is the place to go, except it is sealed off. A better bet is the white sands missile range at Alamagordo, NM where the very first bomb was exploded on the top of a tower, much closer to the ground. (Trinity test. How’s that for blasphemy.)
Well, the test sites at Nevada, or at Bikini and Eniwetok, may not be good examples, since they were subjected to repeated blasts from a variety of A- and H- bombs over years.
(BTW: the fuel in an H-nuke IIRC is tritium – the plutonium is in the initiator, a small A-nuke)
This account of a visit to the Trinity atomic test site 50 years later indicates there was less residual radioactivity than the natural radiation background on a commercial jetliner at cruising altitude. Of course, there have been efforts to “decontaminate” the site with fresh soil brought in from elsewhere.