How does a biological geomagnetic sense work? The Earth is surrounded by a magnetic field, generated by the movement of the planet's liquid core. It's why a magnetic compass points north. At Earth's surface, this magnetic field is fairly weak, about 100 times weaker than that of a refrigerator magnet. Its been proven that animals, such as bees, turtles, and birds have a geomagnetic sense, but do humans? Scientists have tried to investigate whether humans belong on the list of magnetically sensitive organisms. For decades, there's been a back-and-forth between positive reports and failures to demonstrate the trait in people, with seemingly endless controversy. The mixed results in people may be due to the fact that virtually all past studies relied on behavioral decisions from the participants. If human beings do possess a magnetic sense, daily experience suggests that it would be very weak or deeply subconscious.
Skeptics dismissed early reports of these traits in humans, largely because there didn't seem to be a biophysical mechanism that could translate the Earth's weak geomagnetic field into strong neural signals. This view was dramatically changed by the discovery that living cells have the ability to build nanocrystals of the ferromagnetic mineral magnetite, basically, tiny iron magnets. Nevertheless, scientists haven't considered humans to be magnetically sensitive organisms.
However, during recent studies conducted on people sitting alone, in relative silence, inside dark rooms, scientists discovered that they can move a magnetic field silently relative to the brain, but without the brain having initiated any signal to move the head. This is comparable to situations when your head or trunk is passively rotated by somebody else, or when you're a passenger in a vehicle which rotates. Although in certain studies, the brain can become "concerned" with the unexpected change in the magnetic field direction.
"Brains register magnetic shifts, subconsciously. The participants were all unaware of the magnetic field shifts and their brain responses. They felt that nothing had happened during the whole experiment - they'd just sat alone in dark silence for an hour. Underneath, though, their brains revealed a wide range of differences. Some brains showed almost no reaction, while other brains had alpha waves that shrank to half their normal size after a magnetic field shift.", researchers stated.
A human response to Earth-strength magnetic fields might seem surprising, but given the evidence for magnetic sensation in our animal ancestors, it might be more surprising if humans had completely lost every last piece of the system. Thus far, scientists have found evidence that people have working magnetic sensors sending signals to the brain, a previously unknown sensory ability in the subconscious human mind. The full extent of our magnetic inheritance remains to be discovered.
