In physics, mirror matter, also called shadow matter or Alice matter, is a hypothetical counterpart to ordinary matter. Modern physics deals with three basic types of spatial symmetry: reflection, rotation and translation. The known elementary particles respect rotation and translation symmetry but do not respect mirror reflection symmetry (also called P-symmetry or parity). Of the four fundamental interactionsâ€”electromagnetism, the strong interaction, the weak interaction, and gravityâ€”only the weak interaction breaks parity. (Wikipedia)

deinonychus commented on the word mirror matter

In physics, mirror matter, also called shadow matter or Alice matter, is a hypothetical counterpart to ordinary matter. Modern physics deals with three basic types of spatial symmetry: reflection, rotation and translation. The known elementary particles respect rotation and translation symmetry but do not respect mirror reflection symmetry (also called P-symmetry or parity). Of the four fundamental interactionsâ€”electromagnetism, the strong interaction, the weak interaction, and gravityâ€”only the weak interaction breaks parity. (Wikipedia)

January 18, 2012