This page is under construction. In nature we have two kinds of particles. We have fermions that can never be in the same state with other fermions. And then we have bosons.
Bosons have the peculiar tendency of doing the same that other bosons are doing.
When the temperature is lowered sufficiently, a macroscopic number of bosons may end up in the same state. This phenomena was predicted by Einstein and Bose about seventy years ago and is called accordingly Bose-Einstein condensation . Those of you who are not too famialiar with the concepts of quantum physics may think of it like this. You are sitting and watching a circus performance. The show ends are people start clapping hands.