Ed Brayton has a post today pointing to a particularly ignorant monologue by noted bigot Bryan Fischer of the American Family Association. In it Fischer says that
- The strong nuclear force is what holds atomic nuclei together (true),
- scientists don’t understand it (more or less false for decades), so therefore
- the strong nuclear force is Jesus.
This seems to be a version of the “god of the gaps” argument, arguing that things we don’t understand must be due to divine intervention. This is recognized by most people as a logical fallacy. Obviously, when this is applied to things that we actually do understand, it looks bad for religion. It’s also a dangerous argument for science because it encourages people to be incurious about the world. If we ascribe a supernatural origin to everything we don’t understand then there is no need for science; we already have the explanation for any problem.
Just in case anyone wants a brief explanation of the strong force:
Nuclei are made of protons and neutrons. Neutrons have no electric charge while protons are all positively charged. So, the electromagnetic forces between protons tend to try to push them apart – to cause the nucleus to break apart. The nucleus is held together because there is another, stronger force (unimaginatively called the strong force) that pulls the protons together more than electromagnetism pushes them apart. In quantum mechanics (the nucleons are nonrelativistic), this can be roughly modeled as a deep short-range square potential well that replaces the usual 1/r Coulomb potential from electrostatics. The potential is generated by the other nucleons in a nucleus, so this is only a very simple approximation.
In more advanced (but still not fundamental models) the forces between nucleons can be modeled as an exchange of mesons (typically pions), similarly to how electromagnetic interactions are caused by photon exchange between particles. The fundamental interaction comes from the local SU(3) color symmetry of quark fields in quantum chromodynamics. There are 3 colors and 8 bosons (called gluons) that allow for exchange of color charge between particles. The strong force is also what holds the nucleons together – they are made of quarks and gluons, which are all in turn believed to be elementary particles. Calculations of the properties of hadrons (protons, neutrons, pions, etc) from first principles requires the use of the world’s most powerful supercomputers. That is a field called Lattice QCD.
Nuclei are complicated objects made of complicated composite particles, so we can’t feasibly calculate anything we want to arbitrary precision. The strong force is also difficult to deal with it because of it’s large coupling constant (becoming nonperturbative in many problems) and it’s non-Abelian nature (a math term related to the properties of SU(3) that here means that gluons can interact directly with other gluons). We do still have a pretty good understanding of how they work. Fischer only had to look up the nuclear force on Wikipedia if he wanted to get some idea of what we know.