# Why can't I have me a golf-ball sized nuke? **URL:** \ **Category:** Factual Questions\ **Created:** [March 6, 2006, 12:12pm UTC](https://boards.straightdope.com/t/why-cant-i-have-me-a-golf-ball-sized-nuke/347239 "2006-03-06T12:12:11Z")\ **Posts on this page:** 7\ **Page:** 3
**Author:** ![Stranger\_On\_A\_Train](https://avatars.discourse-cdn.com/v4/letter/s/13edae/32.png) [@Stranger\_On\_A\_Train](https://boards.straightdope.com/u/Stranger_On_A_Train)\ **Post date:** [March 7, 2006, 2:18am UTC](https://boards.straightdope.com/t/why-cant-i-have-me-a-golf-ball-sized-nuke/347239/41 "2006-03-07T02:18:29Z")
> [@commasense](#): > > For instance, a golf ball has a diameter of 1.68 inches (4.27 cm), so if I’ve done the math right, a sphere of PU-239 that size would have a mass of about 616 grams, about 1/16th the amount needed for a critical mass sphere. Could that small a mass be pushed into even a little fission explosion? I can’t answer that (I mean I don’t know, not that I can’t say), but Taylor indicated that there were feasible designs for which the entire ‘physics package’ could be held in the palm of a hand, which implies a core not much larger than a golf ball at most. Whether such designs were ever tested is uncertain. Such devices were never (to public knowledge) fielded, nor is it clear what use they’d be. (The notion of using nuclear weapons tactically is laughable at best, and frightening at worst.) As I said, Taylor was really interested in minaturized nuclear devices both out of his own intellectual curiosity and as propulsion bomblets for an ORION-type rocket. > [@drachillix](#): > > I paersonally always wondered if for a more conventionally launched munition you could make a shell that the impact of the projectile crushed a hollow charge of some kind of weapon grade radioactive material into a tight enough ball to go critical[…]Could something like that work or is more force than a rifle bullet impact against a hard surface needed? Unlikely. Compact, efficient nuclear devices require the explosive containment method, and the implosion has to be shaped and time just so in order that the wavefronts don’t interfere with each other and cause an unevent compression. There were some urban legends about a gun-type californium bullet that would explode as suggested but it is unlikely–to a point of absurdity–that such a device could be made to work. Even if one could fabricate enough Ca to make a bullet (and use it before it decays out), and somehow form it into a subcritical shape that would deform to supercritical, it’s unlikely that it would explode efficiently. More than likely it would either deform irregularly (as bullets tend to do when they impact a hard surface) and just give off a lot of gammas but not literally explode, or it would explode prematurely, blowing off most of its mass without reacting. Again, the value of such a weapon is unclear; it’s too big for covert use, too small for effective battlefield use, to unstable to store very long, and undesireable from a proliferation standpoint. (Can you imagine trying to secure such a thing, or tracking it down if stolen?) Stranger ---
**Author:** ![Der\_Trihs](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/der_trihs/32/233_2.png) [@Der\_Trihs](https://boards.straightdope.com/u/Der_Trihs)\ **Post date:** [March 7, 2006, 8:16am UTC](https://boards.straightdope.com/t/why-cant-i-have-me-a-golf-ball-sized-nuke/347239/42 "2006-03-07T08:16:05Z")
> [@Stranger On A Train](#): > > Though you’d think that a disruptor–which suppresses the electric charge on the proton or electron–would tear a GP hull apart too. [Sci fi nerd mode] It’s called a Slaver Disintegrator, and since GP hulls are made of a single _artificially strengthened_ molecule ( by a microscopic generator in the hull ), the logical assumption is that the strengthening field/effect overpowers the disintegrator. [/scifi nerd mode] ---
**Author:** ![Malacandra](https://avatars.discourse-cdn.com/v4/letter/m/45deac/32.png) [@Malacandra](https://boards.straightdope.com/u/Malacandra)\ **Post date:** [March 7, 2006, 9:43am UTC](https://boards.straightdope.com/t/why-cant-i-have-me-a-golf-ball-sized-nuke/347239/43 "2006-03-07T09:43:26Z")
> [@Chronos](#): > > Not quite. Neutronium is only stable in a neutron star. If you somehow managed to remove a lump of neutronium from a neutron star, the neutronium itself would explode, probably significantly more powerfully than the nuke you’re trying to trigger. And again, the devil’s in the details. That word _somehow_ is a biggie. A matchbox-sized lump of neutronium masses about as much as a battleship. But the surface gravity of a large object made of neutronium is in the thousands or millions of gravities. So by the time you have successfully dug out a lump of the stuff (left as an exercise for the student), you’ve got something that’s harder to lift than, at least, all the battle fleets of the world put together - and when I say “harder”, I mean “by several orders of magnitude”. 😛 ---
**Author:** ![Ranchoth](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ranchoth/32/1066_2.png) [@Ranchoth](https://boards.straightdope.com/u/Ranchoth)\ **Post date:** [March 7, 2006, 9:58am UTC](https://boards.straightdope.com/t/why-cant-i-have-me-a-golf-ball-sized-nuke/347239/44 "2006-03-07T09:58:52Z")
> [@Johnny L.A.](#): > > Hijack. > > I heard something about a ‘natural nuclear reactor’. In Africa? IIRC there was a large deposit of unranium that sometime in the past generated a nuclear reaction of some sort. Does anyone have any information on that? Like [this, on the natural fission reactors at Oklo?](http://en.wikipedia.org/wiki/Natural_nuclear_fission_reactor) Only a coupla billion years ago. No beating the W-54, unless you go with Californium, I guess. (Or you get ahold of some Red Mercury—which you might as well ask the White Rabbit for.) ---
**Author:** ![HMS\_Irruncible](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hms_irruncible/32/7394_2.png) [@HMS\_Irruncible](https://boards.straightdope.com/u/HMS_Irruncible)\ **Post date:** [March 7, 2006, 12:12pm UTC](https://boards.straightdope.com/t/why-cant-i-have-me-a-golf-ball-sized-nuke/347239/45 "2006-03-07T12:12:00Z")
Slight nitpick on a previous comment… to get a chain reaction, you only need a critical mass, not a supercritical mass, although in practicality most packages end up being supercritical. Subcritical mass = not enough stuff Critical mass = enough stuff Supercritical mass = more than enough stuff ---
**Author:** ![matt](https://avatars.discourse-cdn.com/v4/letter/m/a6a055/32.png) [@matt](https://boards.straightdope.com/u/matt)\ **Post date:** [March 7, 2006, 12:26pm UTC](https://boards.straightdope.com/t/why-cant-i-have-me-a-golf-ball-sized-nuke/347239/46 "2006-03-07T12:26:45Z")
> [@Brain Wreck](#): > > Slight nitpick on a previous comment… to get a chain reaction, you only need a critical mass, not a supercritical mass, although in practicality most packages end up being supercritical. > > Subcritical mass = not enough stuff > Critical mass = enough stuff > Supercritical mass = more than enough stuff To nitpick the nitpick - a critical mass is where the neutron generation rate is exactly equal to the neutron escape rate. So yes, you get a (barely) sustainable chain reaction, but you don’t get an explosion. It just ticks along, slightly warm, and spitting out neutrons. You need supercriticality to get a boom, and the greater the degree of supercriticality, the more efficient the bomb. ---
**Author:** ![mks57](https://avatars.discourse-cdn.com/v4/letter/m/b9bd4f/32.png) [@mks57](https://boards.straightdope.com/u/mks57)\ **Post date:** [March 7, 2006, 12:35pm UTC](https://boards.straightdope.com/t/why-cant-i-have-me-a-golf-ball-sized-nuke/347239/47 "2006-03-07T12:35:20Z")
> [@Brain Wreck](#): > > Slight nitpick on a previous comment… to get a chain reaction, you only need a critical mass, not a supercritical mass, although in practicality most packages end up being supercritical. > > Subcritical mass = not enough stuff > Critical mass = enough stuff > Supercritical mass = more than enough stuff It’s a little more complicated than that. Critical mass is a function of mass, density, and geometry. [Previous page](https://boards.straightdope.com/t/why-cant-i-have-me-a-golf-ball-sized-nuke/347239.md?page=2)