3 deleted 2 characters in body edited Aug 13 '13 at 16:45 Undo 10.5k99 gold badges5555 silver badges151151 bronze badges As both @AlanSE and @Philipp said, Pu-238 won't go boom no matter what you do to themit. However, lets pretend it was Pu-239 and see what happens. First, the battery puts out only about 1/2% of the power of a Pu-238 battery, Galileo doesn't work at all. Second, while it is just barely possible to make a mass supercritical with pressure, you would have to start with a mass that's just a hair below critical and then subject it to some really extreme pressure. While we think of metal as incompressible, it will squash a bit under planetary core type pressures. Finally, if you manage to do this, you end up with a criticality accident, not a mushroom cloud. The one I recall reading about knocked a nearby worker off a catwalk – he lived long enough to run out of the building. If you want a boom, you have to convert the subcritical mass to a very supercritical mass very quickly – which is why all the complex mess with explosives and very precise detonators. As both @AlanSE and @Philipp said, Pu-238 won't go boom no matter what you do to them. However, lets pretend it was Pu-239 and see what happens. First, the battery puts out only about 1/2% of the power of a Pu-238 battery, Galileo doesn't work at all. Second, while it is just barely possible to make a mass supercritical with pressure, you would have to start with a mass that's just a hair below critical and then subject it to some really extreme pressure. While we think of metal as incompressible, it will squash a bit under planetary core type pressures. Finally, if you manage to do this, you end up with a criticality accident, not a mushroom cloud. The one I recall reading about knocked a nearby worker off a catwalk – he lived long enough to run out of the building. If you want a boom, you have to convert the subcritical mass to a very supercritical mass very quickly – which is why all the complex mess with explosives and very precise detonators. As both @AlanSE and @Philipp said, Pu-238 won't go boom no matter what you do to it. However, lets pretend it was Pu-239 and see what happens. First, the battery puts out only about 1/2% of the power of a Pu-238 battery, Galileo doesn't work at all. Second, while it is just barely possible to make a mass supercritical with pressure, you would have to start with a mass that's just a hair below critical and then subject it to some really extreme pressure. While we think of metal as incompressible, it will squash a bit under planetary core type pressures. Finally, if you manage to do this, you end up with a criticality accident, not a mushroom cloud. The one I recall reading about knocked a nearby worker off a catwalk – he lived long enough to run out of the building. If you want a boom, you have to convert the subcritical mass to a very supercritical mass very quickly – which is why all the complex mess with explosives and very precise detonators. 2 Fixed some typos, corrected grammar and spelling, improved formatting while I was at it ;) edited Aug 1 '13 at 2:49 TildalWave 64.6k1212 gold badges238238 silver badges389389 bronze badges As both AlanSE@AlanSE and Philipp@Philipp said, Pu-238Pu-238 won't go boom no matter what you do to them. However, lets pretend it was Pu-239Pu-239 and see what happens. First, the battery putputs out only about 1/2% of the power of a Pu-238Pu-238 battery, Galileo doesn't work at all. Second, while it is just barely possible to make a mass supercritical with pressure, you would have to start with a mass that's just a hair below critical and then subject it to some really extreme pressure. WhileWhile we thingthink of metal as incompressible, it will squash a bit under planetary core type pressures. Finally, if you manage to do this, you end up with a criticality accident, not a mushroom cloud. TheThe one I recall reading about knocked a nearby worker off a catwalk--he – he lived long enough to run out of the building. IfIf you want a boom, you have to convert the subcritical mass to a very supercritical mass very quickly--which – which is why all the complex mess with explosives and very precise detonators. As both AlanSE and Philipp said, Pu-238 won't go boom no matter what you do to them. However, lets pretend it was Pu-239 and see what happens. First, the battery put out only about 1/2% of the power of a Pu-238 battery, Galileo doesn't work at all. Second, while it is just barely possible to make a mass supercritical with pressure you would have to start with a mass that's just a hair below critical and then subject it to some really extreme pressure. While we thing of metal as incompressible it will squash a bit under planetary core type pressures. Finally, if you manage to do this you end up with a criticality accident, not a mushroom cloud. The one I recall reading about knocked a nearby worker off a catwalk--he lived long enough to run out of the building. If you want a boom you have to convert the subcritical mass to a very supercritical mass very quickly--which is why all the complex mess with explosives and very precise detonators. As both @AlanSE and @Philipp said, Pu-238 won't go boom no matter what you do to them. However, lets pretend it was Pu-239 and see what happens. First, the battery puts out only about 1/2% of the power of a Pu-238 battery, Galileo doesn't work at all. Second, while it is just barely possible to make a mass supercritical with pressure, you would have to start with a mass that's just a hair below critical and then subject it to some really extreme pressure. While we think of metal as incompressible, it will squash a bit under planetary core type pressures. Finally, if you manage to do this, you end up with a criticality accident, not a mushroom cloud. The one I recall reading about knocked a nearby worker off a catwalk – he lived long enough to run out of the building. If you want a boom, you have to convert the subcritical mass to a very supercritical mass very quickly – which is why all the complex mess with explosives and very precise detonators. 1 answered Jul 31 '13 at 22:38 Loren Pechtel 7,0761414 silver badges2626 bronze badges As both AlanSE and Philipp said, Pu-238 won't go boom no matter what you do to them. However, lets pretend it was Pu-239 and see what happens. First, the battery put out only about 1/2% of the power of a Pu-238 battery, Galileo doesn't work at all. Second, while it is just barely possible to make a mass supercritical with pressure you would have to start with a mass that's just a hair below critical and then subject it to some really extreme pressure. While we thing of metal as incompressible it will squash a bit under planetary core type pressures. Finally, if you manage to do this you end up with a criticality accident, not a mushroom cloud. The one I recall reading about knocked a nearby worker off a catwalk--he lived long enough to run out of the building. If you want a boom you have to convert the subcritical mass to a very supercritical mass very quickly--which is why all the complex mess with explosives and very precise detonators.