Stirling Newberry's Journal: Steven Weinberg explains broken and accidental symmetries in physics

I do not know how many readers of Slashdot are also regular readers of the New York Review of Books, however, this article on symmetry in physics sheds light on how the "Standard Model" came to be. It's author is Steven Weinberg, who with Sheldon Glashow and Abdus Salam, was awarded the Nobel Prize winner for Physics in 1979 for unification of the electro-magnetic force with the weak force.

Why read it? It's where to send your non-geek friends when they ask why experiments such as the velocity of neutrinos are interesting, and why anyone would want to spend billions of dollars on figuring out the mass of invisibly small things.

It turned out that the Standard Model obeys certain symmetries that are accidental, in the sense that, though they are not the exact local symmetries on which the Standard Model is based, they are automatic consequences of the Standard Model. These accidental symmetries accounted for a good deal of what had seemed so mysterious in earlier years, and raised interesting new possibilities.

By this he means that not all patterns in physics, are basic patterns, and sometimes the small differences point to whole new worlds in physics. In the case of neutrinos, how much mass they have tells us a great deal about physics.