How do we know which is north and which is south?

North poles are conventionally taken to be the direction of right handed spin, following the right-hand rule in physics.

• The rule works like a corkscrew, in a sense: when you turn a corkscrew to the right it moves forward. Turn it to the left, it moves backward.
• More electrons are emitted toward the south pole of the nucleus of an atom such as cobalt or iron. Similarly, field lines of a bar magnet always point from north to south.
• The Earth rotates on its axis from west to east. According to the right hand rule, "north" is up because turning to the right means Earth is moving toward the "up" pole.

How does a compass work with a magnetic field?

The needle of a compass is a small magnet, one that is allowed to move horizontally. The needle is influenced by the ambient magnetic field of the Earth, and it aligns with the horizontal portion of the field (yes, there is a vertical portion).

This is said to be true everywhere in the universe.

The ancient Greeks would have loved this symmetry. It is built on their concepts, after all. But half a century ago we learned from experiments in quantum mechanics that the universe doesn’t follow Greek rules. It follows Chinese rules.

At very low temperatures, the nuclei of atoms line up in a magnetic field so that they all face the same direction as they spin (their north poles align with the north pole of the magnetic field). However, the electrons in cobalt-60 nuclei shoot towards the south pole of the nucleus while this is happening!

According to standard theories, the weak nuclear force acts on particles in a way that distinguishes between right and left. The existence of a favored direction at the atomic level exerts an influence on us, and on larger objects made from these particles, including our planet and solar system.

Let’s look at our planet from space. Earth spins from west to east (rightward). According to the right hand rule, that must be north at the top, right?

Now look at the magnetic field of Earth. Notice that electrons are moving out of the south pole and towards the north pole.

The only people confused by this are people who absorbed the idea of a symmetrical universe. That’s why Western scientists did not discover this fact (Richard Feynman bet $50 against it).

What we call north and south are conventions, started centuries before Europeans had the compass. These conventions were built upon the belief that the world is symmetrical and that the universe is symmetrical.

We now know that the universe isn’t symmetrical.

More than 50 years ago, a team of Chinese scientists proved to westerners an important fact of quantum mechanics, and reminded us of our cultural bias.

The universe is left-handed. (For people unfamiliar with Yin Yang Theory, left is yang.) The North Pole is not a "north pole." The real North Pole (the magnetic north pole) is what we call the South Pole.

A western compass needle points to geographic north, but it is actually pointing at magnetic south.

When Chinese first invented the compass, the needle was a magnetized ladle or spoon that symbolized many things, including the timekeeping Ladle in the skies (successively Doumou, Nandou, and Beidou). The spoon pointed to geographic south, which is why its name is "the south-pointing spoon." Chinese compasses have always pointed to the magnetic north pole, which we call the geographic South Pole.

When someone talks about the qualities of a polar orientation, ask them whether they mean magnetic or geographic. As you can see, it makes a difference.