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> One proposed version[^1] had the force of more than 600,000 Hiroshimas. Even so, Cold War analysts coolly judged that it could reduce a region the size of Fra

> One proposed version[^1] had the force of more than 600,000 Hiroshimas. Even so, Cold War analysts coolly judged that it could reduce a region the size of France to ashes. His weapon was a planet shaker. It could end civilization. Except... [^1] https://archive.ph/Md1YG https://archive.ph/Md1YG [^1]https://nuclearsecrecy.com/nukemap/ https://nuclearsecrecy.com/nukemap/ Were they just wrong by an order of magnitude or 2 because of previously unforseen limits, like air pressure? Or maybe 100MT is not the same as 600k Hiroshimas. Casually, the blast doesn't look like it's has a similar effect.

MathMonkeyMan 1y ago
Wikipedia says that the bomb that destroyed Hiroshima had a yield of about 16 kilotons of TNT. 600k of those would be 16*600 megatons, or 9600 megatons. That's 96 times more than the original target yield of 100 megatons for Tsar Bomba. I don't know if that's possible, but it makes sense that it would "reduce a region the size of France to ashes." Maybe the design had a lot of stages.
- deleted 1y ago
  [deleted]
- cjbgkagh 1y ago
  IIRC there is no hard limit on the size of a hydrogen bomb. That said many small nukes operating as a cluster cover more area for the same material due to the inverse cubed law.
  - dghlsakjg 1y ago
    AFAIK, you can just pack as much fuel as you want into the secondary to scale the size of a thermonuclear bomb. So yeah, there is no size limit. Interesting aside; the US had the dial-a-yield mechanism that allowed one bomb to deliver a selectable amount of energy, not sure what the mechanism for this was, however. As to your second sentence, pretty sure that’s what a MIRV is.
    - dboreham 1y ago
      Variable yield weapons presumably still exist. Particularly depth charges iirc. Usually the yield can be selected between two or more fixed levels rather than a continuously variable input. Often this is implemented with tricks such as disabling the secondary and/or disabling boosting in the primary.
    - chickenbig 1y ago
      > not sure what the mechanism for this was, however. Boosting (injection of deuterium/tritium into the centre of the pit) causes a large increase in yield because fusion generates lots of high energy neutrons that go on to fast fission your (still compressed) pit. According to one weapons designer, boosting is mainly responsible for the remarkable 100-fold increase in the efficiency of fission weapons since 1945. https://en.wikipedia.org/wiki/Boosted_fission_weapon https://en.wikipedia.org/wiki/Boosted_fission_weapon
CamperBob2 1y ago
Teller really, really wanted to build a gigaton bomb. That may have been what the author was thinking of.
- wat10000 1y ago
  He also proposed a 10 gigaton bomb. It was referred to as a “backyard bomb.” Meaning that you didn’t have to figure out how to put it on a missile or bomber. You could just detonate it in your backyard and it would do the job of destroying the enemy (and everyone else).
mousethatroared 1y ago
Big boom booms are easy. Nuclear bomb design research since the sixties is all about making them as clean and low yield as possible. These two goals are counters to each other, but once you've mastered it your nuclear arsenal becomes less of a garage queen and a lot more useful.
somenameforme 1y ago
Your linked site for some reason doesn't include fallout by default, nor does it seem to factor casualties from it. Turn on fallout + surface burst, and a 100MT bomb's deadly fallout range goes from the center of France (where the label is on their map) to the center of Germany and I suspect that's an extreme underestimation, especially the conic they give. It's also possible that the NYTimes is conflating facts by accident. Your demo link only accounts for single big-blast effects but the way you optimize damage with nukes is lots of smaller bombs, often in a single bomb - MIRV is one name for this. The reason is pretty simple. We approximate the explosive range as a sphere and the volume of that sphere is proportional to the cube (^1/3) of the yield. So if you increase the yield by 10x you only increase the explosive radius by something like 2.15x. On the other hand, detonate 10 bombs side by side and you increase the radius by 10x. This not only maximizes damage, but also works to further nullify any sort of anti-missile defense. And 100MT would be well more than enough to obliterate France. You can also kind of intuit this by thinking about 100MT means. That's 100,000,000 TONS of TNT explosive capacity. That's about 1.5 tons of TNT for each and every person in France. That's just a stupidly massive absurd amount of destruction.
- 05 1y ago
  > detonate 10 bombs side by side and you increase the radius by 10x By 10**.5~=3.2x
  - lostlogin 1y ago
    It’s not very tidy phrasing, but I think the meaning is that 10 detonations next to each other (blast diameters touching) is 10x the diameter?
    - somenameforme 1y ago
      He's right. You'd want to arrange them in a square for comparable coverage so it'd be sqrt(10) = ~3.2. It feels somehow nice and correct that an effort to reduce a 3d problem (basically a lot of our boom goes up or down, which is not necessary in most cases) to a 2d one changes it from a gain of x^(1/3) to x^(1/2).
benbayard 1y ago
I think it's probably referring to this bomb: https://www.youtube.com/watch?v=E55uSCO5D2w https://www.youtube.com/watch?v=E55uSCO5D2w I think the key is proposed weapon, instead of practical weapon. It's a fascinating video, you should check it out!
mikeyouse 1y ago
It’s a reference to this paragraph where they hypothesized about a 10,000MT bomb; > All of which is to say that the idea of making hydrogen bombs in the hundreds-of-megatons yield range was hardly unusual in the late 1950s. If anything, it was tame compared to the gigaton ambitions of one of the H-bomb’s inventors. It is hard to convey the damage of a gigaton bomb, because at such yields many traditional scaling laws do not work (the bomb blows a hole in the atmosphere, essentially). However, a study from 1963 suggested that, if detonated 28 miles (45 kilometers) above the surface of the Earth, a 10,000-megaton weapon could set fires over an area 500 miles (800 kilometers) in diameter. Which is to say, an area about the size of France. Teller’s crazy ass wanted to build a 10,000MT bomb with a 1,000MT primary.. https://en.m.wikipedia.org/wiki/Sundial_(weapon) https://en.m.wikipedia.org/wiki/Sundial_(weapon)

MathMonkeyMan 1y ago

Wikipedia says that the bomb that destroyed Hiroshima had a yield of about 16 kilotons of TNT. 600k of those would be 16*600 megatons, or 9600 megatons. That's 96 times more than the original target yield of 100 megatons for Tsar Bomba. I don't know if that's possible, but it makes sense that it would "reduce a region the size of France to ashes." Maybe the design had a lot of stages.

deleted 1y ago
[deleted]
cjbgkagh 1y ago
IIRC there is no hard limit on the size of a hydrogen bomb. That said many small nukes operating as a cluster cover more area for the same material due to the inverse cubed law.
- dghlsakjg 1y ago
  AFAIK, you can just pack as much fuel as you want into the secondary to scale the size of a thermonuclear bomb. So yeah, there is no size limit. Interesting aside; the US had the dial-a-yield mechanism that allowed one bomb to deliver a selectable amount of energy, not sure what the mechanism for this was, however. As to your second sentence, pretty sure that’s what a MIRV is.
  - dboreham 1y ago
    Variable yield weapons presumably still exist. Particularly depth charges iirc. Usually the yield can be selected between two or more fixed levels rather than a continuously variable input. Often this is implemented with tricks such as disabling the secondary and/or disabling boosting in the primary.
  - chickenbig 1y ago
    > not sure what the mechanism for this was, however. Boosting (injection of deuterium/tritium into the centre of the pit) causes a large increase in yield because fusion generates lots of high energy neutrons that go on to fast fission your (still compressed) pit. According to one weapons designer, boosting is mainly responsible for the remarkable 100-fold increase in the efficiency of fission weapons since 1945. https://en.wikipedia.org/wiki/Boosted_fission_weapon https://en.wikipedia.org/wiki/Boosted_fission_weapon

CamperBob2 1y ago

Teller really, really wanted to build a gigaton bomb. That may have been what the author was thinking of.

wat10000 1y ago
He also proposed a 10 gigaton bomb. It was referred to as a “backyard bomb.” Meaning that you didn’t have to figure out how to put it on a missile or bomber. You could just detonate it in your backyard and it would do the job of destroying the enemy (and everyone else).

mousethatroared 1y ago

Big boom booms are easy. Nuclear bomb design research since the sixties is all about making them as clean and low yield as possible. These two goals are counters to each other, but once you've mastered it your nuclear arsenal becomes less of a garage queen and a lot more useful.

somenameforme 1y ago

Your linked site for some reason doesn't include fallout by default, nor does it seem to factor casualties from it. Turn on fallout + surface burst, and a 100MT bomb's deadly fallout range goes from the center of France (where the label is on their map) to the center of Germany and I suspect that's an extreme underestimation, especially the conic they give. It's also possible that the NYTimes is conflating facts by accident. Your demo link only accounts for single big-blast effects but the way you optimize damage with nukes is lots of smaller bombs, often in a single bomb - MIRV is one name for this. The reason is pretty simple. We approximate the explosive range as a sphere and the volume of that sphere is proportional to the cube (^1/3) of the yield. So if you increase the yield by 10x you only increase the explosive radius by something like 2.15x. On the other hand, detonate 10 bombs side by side and you increase the radius by 10x. This not only maximizes damage, but also works to further nullify any sort of anti-missile defense. And 100MT would be well more than enough to obliterate France. You can also kind of intuit this by thinking about 100MT means. That's 100,000,000 TONS of TNT explosive capacity. That's about 1.5 tons of TNT for each and every person in France. That's just a stupidly massive absurd amount of destruction.

05 1y ago
> detonate 10 bombs side by side and you increase the radius by 10x By 10**.5~=3.2x
- lostlogin 1y ago
  It’s not very tidy phrasing, but I think the meaning is that 10 detonations next to each other (blast diameters touching) is 10x the diameter?
  - somenameforme 1y ago
    He's right. You'd want to arrange them in a square for comparable coverage so it'd be sqrt(10) = ~3.2. It feels somehow nice and correct that an effort to reduce a 3d problem (basically a lot of our boom goes up or down, which is not necessary in most cases) to a 2d one changes it from a gain of x^(1/3) to x^(1/2).

benbayard 1y ago

I think it's probably referring to this bomb: https://www.youtube.com/watch?v=E55uSCO5D2w https://www.youtube.com/watch?v=E55uSCO5D2w I think the key is proposed weapon, instead of practical weapon. It's a fascinating video, you should check it out!

mikeyouse 1y ago

It’s a reference to this paragraph where they hypothesized about a 10,000MT bomb; > All of which is to say that the idea of making hydrogen bombs in the hundreds-of-megatons yield range was hardly unusual in the late 1950s. If anything, it was tame compared to the gigaton ambitions of one of the H-bomb’s inventors. It is hard to convey the damage of a gigaton bomb, because at such yields many traditional scaling laws do not work (the bomb blows a hole in the atmosphere, essentially). However, a study from 1963 suggested that, if detonated 28 miles (45 kilometers) above the surface of the Earth, a 10,000-megaton weapon could set fires over an area 500 miles (800 kilometers) in diameter. Which is to say, an area about the size of France. Teller’s crazy ass wanted to build a 10,000MT bomb with a 1,000MT primary.. https://en.m.wikipedia.org/wiki/Sundial_(weapon) https://en.m.wikipedia.org/wiki/Sundial_(weapon)