History of Broken Symmetry
I’m not a physicist, but this story fascinates me to no end. Human being loves symmetry and nature tends to be symmetrical. But there are instances of natural broken symmetries. Magnetism for example. When north is “preferred” than south, it breaks a symmetry.
Imagine, you come to an empty dinner table. The table is set for 10 people, and already has 10 glasses. The glasses are to the left and to the right of each chair. When all 10 people sit down, they have symmetrical arrangement. One glass on each side of everyone. But, when one person starts to drink, and he lifts the glass to his right, everybody else has to choose the glass to his right as well.
The symmetry is broken.
Maybe not everyone prefers to drink with his right hand, but his choice is already determined by the history (the first choice made). Nature is (or was) always symmetrical.
This explanation is due to Abdus Salam, 1979 Physics Nobel Prize.