Do the fundamental constants of nature vary in spacetime?
The fundamental constants of Nature, as the name suggests, play a very important role in the Universe. The speed of light sets the Universal speed limit and the electric charge sets the scale for the interaction between atoms and molecules. The Planck constant determines the scale at which quantum mechanics becomes important. Combining these three quantities gives something called the fine structure constant. The fine structure constant is just a number (i.e. no units) and since it is a combination of constants, it too should be a constant – it shouldn’t vary in space and time. But why ‘should’ it be a constant? There is no principle that says constants should really be constant and there is no theory which lets you calculate their value. That is, the fundamental constants are assumed to be constant. The idea of varying constants is not new and many modern theories have room for varying constants. Can these new theories be tested? If the fine structure constant were to vary over very l
