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Estimating a nuclear blast with bits of paper

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Re: Estimating a nuclear blast with bits of paper

#11

Post by dragonwriter »

mikeash wrote: post #8
VLM wrote: post #7

Lets see if I can replicate his mental math. Assuming a lot of spherical cows. A Zeppelin weighs like 200 tons and is about 10 million cubic feet of gas. I did cheat and look that up, everything else, including all the following mistakes, was messed up in my own head. 10 KT of TNT is 10e3/0.2e3 or 50 Zeppelins of gas when it goes boom aka 50 * 10 M cu ft = 500 million cu feet of gas. So my theory is ten miles out the…

According to the NUKEMAP, the survival rate at 10 miles of a 1 megaton bomb should be pretty good: https://nuclearsecrecy.com/nukemap/ That gives 2.5km as the lethal radius for radiation, 3km as the 100% lethal radius for blast, 7km as the radius for "injuries are universal, fatalities are widespread" and 12.6km as the radius for 3rd degree burns from thermal radiation. At 16 km you'd still get badly burned if you we…

> I never understood why "duck and cover" ended up with such a bad reputation.

Because in the the probability of being in a location where it would make a difference​ to even short-term survival was minimal, and, in the event of a major superpower exchange (the main plausible scenario when those drills were common for anything that would include attacks on US population centers) short-survival was widely perceived (with some good reasons) to most likely buy you a long, painful death from a combination of the effects of fallout and those of the effects of the collapse of organized society.

Re: Estimating a nuclear blast with bits of paper

#12

Post by daxfohl »

mikeash wrote: post #8
VLM wrote: post #7

Lets see if I can replicate his mental math. Assuming a lot of spherical cows. A Zeppelin weighs like 200 tons and is about 10 million cubic feet of gas. I did cheat and look that up, everything else, including all the following mistakes, was messed up in my own head. 10 KT of TNT is 10e3/0.2e3 or 50 Zeppelins of gas when it goes boom aka 50 * 10 M cu ft = 500 million cu feet of gas. So my theory is ten miles out the…

According to the NUKEMAP, the survival rate at 10 miles of a 1 megaton bomb should be pretty good: https://nuclearsecrecy.com/nukemap/ That gives 2.5km as the lethal radius for radiation, 3km as the 100% lethal radius for blast, 7km as the radius for "injuries are universal, fatalities are widespread" and 12.6km as the radius for 3rd degree burns from thermal radiation. At 16 km you'd still get badly burned if you we…

Per thermal radiation, does that mean essentially light? So if you see the explosion, no time to get out of the way, already burned?

Re: Estimating a nuclear blast with bits of paper

#13

Post by wayn3 »

daxfohl wrote: post #12
mikeash wrote: post #8

Earlier quoted context omitted.

According to the NUKEMAP, the survival rate at 10 miles of a 1 megaton bomb should be pretty good: https://nuclearsecrecy.com/nukemap/ That gives 2.5km as the lethal radius for radiation, 3km as the 100% lethal radius for blast, 7km as the radius for "injuries are universal, fatalities are widespread" and 12.6km as the radius for 3rd degree burns from thermal radiation. At 16 km you'd still get badly burned if you we…

Per thermal radiation, does that mean essentially light? So if you see the explosion, no time to get out of the way, already burned?

- if you "see" the flash, thats the last thing youre ever going to see. will blind you.

- thermal radiation is, in fact, light, which travels at the speed of light - but you should not imagine the entirety of the thermal energy to be released by a nuclear weapon to be released instantaneously in a radially travelling sphere. that being said, youre not going to outrun such an explosion. where you are at the time of detonation pretty much determines your odds of survival.

Re: Estimating a nuclear blast with bits of paper

#14

Post by wayn3 »

mikeash wrote: post #8
VLM wrote: post #7

Lets see if I can replicate his mental math. Assuming a lot of spherical cows. A Zeppelin weighs like 200 tons and is about 10 million cubic feet of gas. I did cheat and look that up, everything else, including all the following mistakes, was messed up in my own head. 10 KT of TNT is 10e3/0.2e3 or 50 Zeppelins of gas when it goes boom aka 50 * 10 M cu ft = 500 million cu feet of gas. So my theory is ten miles out the…

According to the NUKEMAP, the survival rate at 10 miles of a 1 megaton bomb should be pretty good: https://nuclearsecrecy.com/nukemap/ That gives 2.5km as the lethal radius for radiation, 3km as the 100% lethal radius for blast, 7km as the radius for "injuries are universal, fatalities are widespread" and 12.6km as the radius for 3rd degree burns from thermal radiation. At 16 km you'd still get badly burned if you we…

the bomb does not explode "near" the ground.

the relatively small bombs of hiroshima and nagsaki exploded about a mile above ground. the goal here is to make the shockwaves double up near the ground, causing more destruction.

i'd assume that bigger bombs would detonate at higher altitudes to achieve the same effect further out.

Re: Estimating a nuclear blast with bits of paper

#15

Post by daxfohl »

wayn3 wrote: post #13
daxfohl wrote: post #12

Earlier quoted context omitted.

Per thermal radiation, does that mean essentially light? So if you see the explosion, no time to get out of the way, already burned?

- if you "see" the flash, thats the last thing youre ever going to see. will blind you. - thermal radiation is, in fact, light, which travels at the speed of light - but you should not imagine the entirety of the thermal energy to be released by a nuclear weapon to be released instantaneously in a radially travelling sphere. that being said, youre not going to outrun such an explosion. where you are at the time of de…

Trying to figure out the most rational thing to do at each distance. In fireball, say goodbye. Sounds like shock wave isn't that big of a deal on its own far beyond the fireball region, beyond eardrums, but obviously shrapnel and collapses will get you indirectly. But thermal radiation seems to extend much farther per the website and there's no escape. So is that what actually kills the most people? (Though it's 2017, who ever goes outside anymore?) And then of course fallout, but I guess you can flee or shelter from that.

Re: Estimating a nuclear blast with bits of paper

#16

Post by albemuth »

mikeash wrote: post #8
VLM wrote: post #7

Lets see if I can replicate his mental math. Assuming a lot of spherical cows. A Zeppelin weighs like 200 tons and is about 10 million cubic feet of gas. I did cheat and look that up, everything else, including all the following mistakes, was messed up in my own head. 10 KT of TNT is 10e3/0.2e3 or 50 Zeppelins of gas when it goes boom aka 50 * 10 M cu ft = 500 million cu feet of gas. So my theory is ten miles out the…

According to the NUKEMAP, the survival rate at 10 miles of a 1 megaton bomb should be pretty good: https://nuclearsecrecy.com/nukemap/ That gives 2.5km as the lethal radius for radiation, 3km as the 100% lethal radius for blast, 7km as the radius for "injuries are universal, fatalities are widespread" and 12.6km as the radius for 3rd degree burns from thermal radiation. At 16 km you'd still get badly burned if you we…

I'm reminded of Ender's Game playing with this.

Re: Estimating a nuclear blast with bits of paper

#17

Post by mikeash »

wayn3 wrote: post #14
mikeash wrote: post #8

Earlier quoted context omitted.

According to the NUKEMAP, the survival rate at 10 miles of a 1 megaton bomb should be pretty good: https://nuclearsecrecy.com/nukemap/ That gives 2.5km as the lethal radius for radiation, 3km as the 100% lethal radius for blast, 7km as the radius for "injuries are universal, fatalities are widespread" and 12.6km as the radius for 3rd degree burns from thermal radiation. At 16 km you'd still get badly burned if you we…

the bomb does not explode "near" the ground. the relatively small bombs of hiroshima and nagsaki exploded about a mile above ground. the goal here is to make the shockwaves double up near the ground, causing more destruction. i'd assume that bigger bombs would detonate at higher altitudes to achieve the same effect further out.

Trinity was on top of a tower, and Fermi was 10 miles away. A half sphere is much closer to that situation than a full sphere.

Re: Estimating a nuclear blast with bits of paper

#18

Post by mikeash »

dragonwriter wrote: post #11
mikeash wrote: post #8

Earlier quoted context omitted.

According to the NUKEMAP, the survival rate at 10 miles of a 1 megaton bomb should be pretty good: https://nuclearsecrecy.com/nukemap/ That gives 2.5km as the lethal radius for radiation, 3km as the 100% lethal radius for blast, 7km as the radius for "injuries are universal, fatalities are widespread" and 12.6km as the radius for 3rd degree burns from thermal radiation. At 16 km you'd still get badly burned if you we…

> I never understood why "duck and cover" ended up with such a bad reputation. Because in the the probability of being in a location where it would make a difference​ to even short-term survival was minimal, and, in the event of a major superpower exchange (the main plausible scenario when those drills were common for anything that would include attacks on US population centers) short-survival was widely perceived (w…

The probability of being in a location where it would make a difference was high. Huge parts of major cities would be in that zone.

Duck and cover dates from the 1950s, where the US's end of nuclear war would have looked much closer to a strangelovian "hair mussed" than the total apocalypse you describe. The Soviet Union didn't have the capability to cause that level of damage to the US until the mid 1960s or so.

Re: Estimating a nuclear blast with bits of paper

#19

Post by mikeash »

daxfohl wrote: post #15
wayn3 wrote: post #13

Earlier quoted context omitted.

- if you "see" the flash, thats the last thing youre ever going to see. will blind you. - thermal radiation is, in fact, light, which travels at the speed of light - but you should not imagine the entirety of the thermal energy to be released by a nuclear weapon to be released instantaneously in a radially travelling sphere. that being said, youre not going to outrun such an explosion. where you are at the time of de…

Trying to figure out the most rational thing to do at each distance. In fireball, say goodbye. Sounds like shock wave isn't that big of a deal on its own far beyond the fireball region, beyond eardrums, but obviously shrapnel and collapses will get you indirectly. But thermal radiation seems to extend much farther per the website and there's no escape. So is that what actually kills the most people? (Though it's 2017…

The thermal pulse lasts several seconds for a large bomb. If you can immediately throw yourself into a ditch or behind a wall or otherwise shelter from it, you may greatly reduce the burns you receive.

What kills the most people depends on the size of the bomb. For really small ones (like the US Army's nuclear bazooka from the 50s) the prompt radiation has the greatest lethal radius. For medium sized ones like Hiroshima, blast is the major one. For really big ones, thermal effects reach the farthest.

Re: Estimating a nuclear blast with bits of paper

#20

Post by cocoablazing »

daxfohl wrote: post #15
wayn3 wrote: post #13

Earlier quoted context omitted.

- if you "see" the flash, thats the last thing youre ever going to see. will blind you. - thermal radiation is, in fact, light, which travels at the speed of light - but you should not imagine the entirety of the thermal energy to be released by a nuclear weapon to be released instantaneously in a radially travelling sphere. that being said, youre not going to outrun such an explosion. where you are at the time of de…

Trying to figure out the most rational thing to do at each distance. In fireball, say goodbye. Sounds like shock wave isn't that big of a deal on its own far beyond the fireball region, beyond eardrums, but obviously shrapnel and collapses will get you indirectly. But thermal radiation seems to extend much farther per the website and there's no escape. So is that what actually kills the most people? (Though it's 2017…

The shock wave is a serious hazard to personnel far beyond the fireball. Just a few pounds of dynamic overpressure presents a hurricane-force wind hazard, and five will result in catastrophic damage to non-hardened structures and a near complete loss of life. The shock front detaches quite early from the fireball. The classic scary videos of residential structures annihilated during nuclear testing were sampled from beyond the maximum fireball radii.
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