It doesn’t take a brilliant observer to confirm that the universe contains a
large variety of different things: ships, shoes, sealing wax, cabbages, kings,
galaxies, and what have you. From a cosmologist’s viewpoint, though, cab-
bages and kings are nearly indistinguishable – the main difference between
them is that the mean mass per king is greater than the mean mass per cab-
bage. From a cosmological viewpoint, the most significant difference between
the different components of the universe is that they are made of different
elementary particles.