The Sacred, Spherical Cows of Physics - Issue 13: Symmetry
▻http://nautil.us/issue/13/symmetry/the-sacred-spherical-cows-of-physics
Early in their training, many physics students come across the idea of spherical cows. Cows in the real world—even at their most plump and well-fed—are hardly spherical, and this makes it tricky to calculate things like, say, how their volume or surface area scales with their height. But students learn that these numbers are easy to calculate if they assume the cow is a perfect sphere, or in other words, that it has spherical symmetry. The lesson: Hard problems become easier when certain underlying (though approximate) symmetries are enforced. The lessons of the spherical cow don’t end with the undergraduate classroom, though. They extend to the very forefront of physics. The theoretical physics community of the 1980s and 1990s was split by debates over the reality of symmetries similar (...)