Describe infinity in 500 words? It shouldn’t be too hard: infinity, though large, can fit nicely into any sized circle.

Nothing in this physical universe is infinite. Not even were you to count every quark and fleeting particle that had ever existed would you come close. Infinity would still be very, even infinitely, far off. For no matter how small a thing is, if it has any size, weight or energy at all, then this universe cannot contain an infinite number of them. And yet in another sense, a mathematical sense, there are many infinities in our universe, some larger than others and all of them can be encompassed by the human mind.

It is one of the strange aspects of our universe, among all possible universes – perhaps its defining strangeness – that ours has been able to evolve beings who can conceive of the infinite. We cannot count to infinity but we can encompass it. Not only that but manipulate it, do calculations with it, puzzle ourselves with its paradoxical qualities. In fact physicists use infinity rather regularly to make their models of this finite universe add up and work.