Were people really vapourised at Hiroshima/Nagasaki?

[running_coach]

Reported the SPNZ link as spam. (lamynn)

[GythaOgg]

@bonzer

Does Hersey actually say anything of the sort? The Wikipedia page on the book cites a footnote 7 for “people with melted eyeballs, or people vaporized, leaving only their shadows etched onto walls” that points to pages 69 and 96 of an 1973 Knopf edition of the book. Checking against a copy of the 1946 Knopf hardback, p69 (or rather p68) covers the melted eyeballs, but p96 corresponds to this passage in the original New Yorker article:

Which seems rather cautious on the whole matter. There’s no suggestion that people were vapourised or that this left a pile of ashes. (Which somehow survived being blown away by the later blast wave?)

I’m not sure that Hersey ever otherwise expanded on the matter in any later editions of the article/book.

I don’t believe Hersey did, but there are existing accounts from survivors who were in or passed through the hypocenter area in the period between the explosion and the firestorm that describe burned bodies lying in the streets everywhere - not piles of ashes. Akiko Takakura’s testimony is one of these. Another one was teacher Katsuko Horibe who was working at Honkawa Elementary School, quite close to the Aioi bridge.

[Leo_Bloom]

@joema

There are various ways to calculate this, whether “vaporize” means treating the body as water and flashing it to steam (it’s 70% water), or disassociating all atomic bonds like a Star Trek phaser. Either way it appears the Hiroshima bomb did not remotely have enough energy for either one.

Using heat of vaporization for a human-body-size water vessel, this is 142 mega Joules: Excerpts From The Mad Scientist’s Handbook: So You’re Ready to Vaporize a Human | Scientific American

…

Great post, as others have said.

How long (more than “instantaneous”) would the vaporization take?

Do ballistics/nuke physicists have to calculate that? Because the more time, the less energy left for the remaining stuff to get vaporized.

[Chronos]

Vaporization takes the same amount of energy regardless of how much time it’s delivered over. The only wrinkle is that adding that much energy won’t necessary vaporize an object: You might just vaporize part of it, and then heat that vapor up a lot, if the energy isn’t transported efficiently through the entire object.

[bonzer]

@GythaOgg

I don’t believe Hersey did, but there are existing accounts from survivors who were in or passed through the hypocenter area in the period between the explosion and the firestorm that describe burned bodies lying in the streets everywhere - not piles of ashes. Akiko Takakura’s testimony is one of these. Another one was teacher Katsuko Horibe who was working at Honkawa Elementary School, quite close to the Aioi bridge.

Agreed.

An additional point that should be made is that relatively few of such bodies were ever photographed and I’m not sure that many such photographs can be tied to specific locations.
Which is utterly understandable. Hardly anyone was taking such photographs and the main priority of the Japanese authorities in the aftermath was to cremate such bodies.
This has had the result that, with some exceptions, the vast majority of photographs of both cities in the aftermath are devoid of obvious human remains. But that’s usually because the bodies had been systematically removed by the time the photos were taken.

(If you can access it, last night’s BBC Radio 4 documentary on Hersey and Hiroshima, tied to the publication anniversary - links here - is worth a listen.)

[Blake]

@Magiver

Hit some spare ribs with an acetylene torch the size of the ribs and see what happens.

I expect that nothing much more would happen. The surface of the meat exposed to a normal blowtorch for a second will dehydrate and probably char a little. The underside will be raw and cold.

If the area of meat is the entire surface of the meat, then the entire surface of the meat will dehydrate and probably char a little, and the underside will be cold and raw.

Do you have any reason to believe that the size of the blowtorch would have any additional effect at all?

Aluminum melts at 993k. that’s a third of the temperature people were exposed to.

And?

I have melted literally thousands of aluminium cans in camp fires. No need for furnaces or bellows or any special equipment. I cooked on the exact same fires at the exact same time.

The point is that aluminium melts at a surprisingly low temperature. A temperature that is three times that hot (whatever that means in practical terms) really isn’t all that impressive.