Fundamental constants are needed to get working versions of the mathematical models we use to explain our observations. But their values are entirely derived from experimental measurements.

Constants are supposed to be, well, constant. In physics there are a number of fundamental constants, such as the speed of light, Planck's constant, and the charge of an electron that are ...

3–17.) This one is a bit of a disappointment. We have fifteen particles in the Standard Model: the six quarks, six leptons, the W, Z, and the Higgs boson, that all have a rest mass.

Time constants had a power-law distribution and the distribution of amplitudes was exponential (Fig. 8a, where we used A for one exponential and A 1 + A 2 for two exponentials).

Our constants could vary both in time and in space. If the extra dimensions of space were to change in size, the “constants” in our three-dimensional world would change with them.

Our constants could vary both in time and in space. If the extra dimensions of space were to change in size, the "constants" in our three-dimensional world would change with them.

Some exotic theories of physics predict that fundamental constants like the speed of light will change over time. Here's how physicists look for that change, illustrated with cute-kid photos.

The values of many forces and particles in the universe, represented by some 30 so-called fundamental constants, all seem to line up perfectly to enable the evolution of intelligent life.