ABSTRACT
A sensory organ for magnetism could be constructed with a magnetic material somewhere in the body, and that material might produce nerve signals to the brain. Close studies of pigeons have also shown that their brains receive signals of magnetic changes via a number of other nervous pathways, signals with an unknown origin. Electrons normally move in pairs, two and two, around a molecule. The photon gives one of the electrons an energy kick and sends it over to a neighboring molecule. The bogong butterfly lives and breeds in the plains of south-eastern Australia, but each spring millions of these nocturnal butterflies fly to spend the winter in caves in mountainous regions one thousand miles away.
