posted on Nov, 4 2003 @ 09:16 AM
But can the plutonium on Galileo explode like a bomb? No, it can't. That's because it's the wrong kind of plutonium. Like all elements, Pu has
different isotopes. This means that in the nucleus of the atom, there are different numbers of neutrons. All plutonium atoms have 94 protons, but some
of these atoms might have 144 neutrons, or 145. These isotopes are designated by the total number of protons plus neutrons. Plutonium 239, for
example, has 94 protons and 145 neutrons.
These isotopes have different properties. The atomic nucleus of Pu239, for example, will split when hit by a neutron. This releases a lot of energy,
as well as more neutrons. These hit other Pu239 atoms, which split, generating more neutrons, etc. This is called a chain reaction, and if there is
enough Pu239 you get a runaway process, which is what powers an atomic (fission) bomb.
However, not all isotopes of Pu do this. Pu238, for example, won't. Although it can split, the products of this fission (called the daughters of the
fission) just don't have the right characteristics to create a chain reaction, let alone a runaway process. In other words, the Pu238 aboard Galileo
is simply not capable of exploding like a bomb.