what actually happens to someone in an atomic bomb explosion?

Question

I saw a post on here showing the ‘shadow’ of a boy standing near the Hiroshima & Nagasaki bomb explosion, it’s not actually his shadow but just the spot that didn’t get ‘bleached’ by the damage of the explosion. I read that he was vaporized in quite a lot of comments on this case but one comment explained that the boy wasn’t actually vaporized, but how did he actually die? Where is his corpse or what’s left of it? How is the damage of atomic bombs different than ‘normal’ bombs used in wars?

In: 20

Answer 1

Nuclear bombs have different effects that extend to different radii. What you get hit with depends on the bomb and height of detonation.

Fireball: This is vaporized, you instantly cease to exist. Bombs like in Hiroshima are usually air burst, so the fireball doesn’t touch the ground and nobody is vaporized. The fireball radius is relatively small compared to the other effects, and detonating it low enough to use the fireball means attenuating the other effects. So air burst is preferred unless it’s a very hard target.

After this, all effects taper off at a distance, but radii are established for a certain known degree of effect.

Thermal radiation: This is an extreme heat that lasts only milliseconds, and it’s only line of sight from the explosion. Everything gets cooked, but only to a shallow depth. People get instant burns, fence posts are charred only on the facing side, and stone surfaces are altered. This is your bleaching, and you see shadows where the radiation is blocked. Granite even gets rough because the smooth surface crystals are melted and refreeze.

Absorption of the radiation even depends on color. A white paper sign hanging far from the blast was unaffected, except that the letters in black were burned out.

Ionizing radiation: Instant lethal dose for 50% of those exposed, dead within a week (although most will still probably die later).

Blast: Extreme over pressure enough to instantly crush a person and wipe out concrete buildings.

Edit: Oh yes, the answer on how he died. He got hit with the thermal radiation instantly upon detonation, and then the blast took him out some milliseconds later. He probably didn’t even know he was burned.