# What is the largest nuclear bomb that could be built? **URL:** \ **Category:** Factual Questions\ **Created:** [November 8, 2012, 10:56pm UTC](https://boards.straightdope.com/t/what-is-the-largest-nuclear-bomb-that-could-be-built/640420 "2012-11-08T22:56:40Z")\ **Posts on this page:** 5\ **Page:** 4
**Author:** ![AK84](https://avatars.discourse-cdn.com/v4/letter/a/85e7bf/32.png) [@AK84](https://boards.straightdope.com/u/AK84)\ **Post date:** [October 29, 2013, 3:05am UTC](https://boards.straightdope.com/t/what-is-the-largest-nuclear-bomb-that-could-be-built/640420/61 "2013-10-29T03:05:15Z")
> [@Lemur866](#): > > The Earth isn’t held together because it’s a solid lump of rock. It’s held together by gravity. If you could take a giant laser beam and slice the Earth in half nothing would happen, the two haves would just smush back together again. > > The way to think of it is, to crack the Earth apart you have to throw material into space at faster than Earth’s escape velocity. To do this to a large fraction of Earth’s material would require an awful lot of energy. No, not the amount you’re thinking of, even more than that. Lots more. Keep going. You’re still not even close. :eek: So George lied? They really could not have destroyed Alderaan. ---
**Author:** ![Lumpy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lumpy/32/446_2.png) [@Lumpy](https://boards.straightdope.com/u/Lumpy)\ **Post date:** [October 29, 2013, 1:47pm UTC](https://boards.straightdope.com/t/what-is-the-largest-nuclear-bomb-that-could-be-built/640420/62 "2013-10-29T13:47:18Z")
> [@AK84](#): > > :eek: So George lied? They really could not have destroyed Alderaan. Oh no, a powerful enough\* beam would do it. In fact, given how fast Alderaan exploded, the beam must have been powerful enough to destroy not just a terrestrial planet but a Jupiter-sized gas giant. \*like, the output of the sun for a couple of hours ---
**Author:** ![Galactapuss](https://avatars.discourse-cdn.com/v4/letter/g/41988e/32.png) [@Galactapuss](https://boards.straightdope.com/u/Galactapuss)\ **Post date:** [May 7, 2014, 6:12am UTC](https://boards.straightdope.com/t/what-is-the-largest-nuclear-bomb-that-could-be-built/640420/63 "2014-05-07T06:12:09Z")
If the question includes only fission bombs, there is an upper range (cite Richard Rhodes, The Making Of The Atomic Bomb, page unknown) because chain reaction- the runaway production of neutrons- propagates faster than the expansion of the medium (the blast wave). You can pile more and more uranium or plutonium in one place, but beyond a certain amount the blast wave outpaces the fission reaction and blows the remaining fissile material away from the reaction. If the question also includes fusion bombs, then there is no upper limit. The fusion reaction propagates as fast or faster than the blast wave. You can keep piling more and more material (deutrium, aka heavy water) in one place and you will get a larger and larger explosion. Yes, there is an upper limit to the size of a bomb that can be carried by sea or land or air, but the question isn’t about the largest movable bomb. Yes, beyond around 100mt any extra explosive power will tend to lift a chunk of atmosphere into space instead of increasing the ground-level blast radius, but the question isn’t about the largest effective bomb that could be built or the maximum blast radius. The answer would appear to be that, given enough manpower, technical skill, resources, and material, there is no upper limit to the explosive power of a nuclear bomb. ---
**Author:** ![Little\_Pig](https://avatars.discourse-cdn.com/v4/letter/l/c57346/32.png) [@Little\_Pig](https://boards.straightdope.com/u/Little_Pig)\ **Post date:** [May 7, 2014, 6:16am UTC](https://boards.straightdope.com/t/what-is-the-largest-nuclear-bomb-that-could-be-built/640420/64 "2014-05-07T06:16:26Z")
> [@The\_Second\_Stone](#): > > The National Ignition Facility in Livermore, California uses the pressure of laser beams on a small pellet to trigger a small fusion reaction, no fission required. There are other kinds of fusion reactors that do not use fission. Please don’t talk about The National Ignition Facility in Livermore, California. I live near there, upon the [Hayward Fault.](http://en.wikipedia.org/wiki/Hayward_Fault_Zone) I have enough to worry about. Thanks. 🙂 ---
**Author:** ![filmstar-en](https://avatars.discourse-cdn.com/v4/letter/f/50afbb/32.png) [@filmstar-en](https://boards.straightdope.com/u/filmstar-en)\ **Post date:** [May 8, 2014, 1:45pm UTC](https://boards.straightdope.com/t/what-is-the-largest-nuclear-bomb-that-could-be-built/640420/65 "2014-05-08T13:45:12Z")
> [@Lemur866](#): > > The Earth isn’t held together because it’s a solid lump of rock. It’s held together by gravity. If you could take a giant laser beam and slice the Earth in half nothing would happen, the two haves would just smush back together again. > > The way to think of it is, to crack the Earth apart you have to throw material into space at faster than Earth’s escape velocity. To do this to a large fraction of Earth’s material would require an awful lot of energy. No, not the amount you’re thinking of, even more than that. Lots more. Keep going. You’re still not even close. > [@AK84](#): > > How big do they have to get before they crack the earth like an egg? Seriously. :dubious: Hmm, so the plot of “Crack in the World” (1965) was a just a flight of fancy? [![](https://img.youtube.com/vi/lHtZ6Ixeqvs/hqdefault.jpg "Crack in the World Trailer") ](https://www.youtube.com/watch?v=lHtZ6Ixeqvs) Let it not be said the Hollywood would let scientific detail stand in the way of good disaster movie. [Previous page](https://boards.straightdope.com/t/what-is-the-largest-nuclear-bomb-that-could-be-built/640420.md?page=3)