66 The Poetry of Physics and The Physics of Poetry
it. So long after we have described planetary motion in terms of inertia
and gravity, we are still left with the question of how do two masses
separated by a distance with nothing but empty space between them,
exert a pull on each other. The only answer we can give is they do
because they do. This is the way our universe is constructed. Can you
think of a better way? I can’t. Physics only describes the universe in
terms of a small number of principles or laws but it cannot explain why
these basic laws are the way they are. There are certain basic laws or
principles upon which physicists build their description of the universe
and all we can do is to describe these laws or principals. Explaining why
they exist or why the universe exists are not questions amenable to
scientific analysis.