Everything that comes into contact with the mass of air surrounding the earth is subjected to?

When compass is placed on the surface of Earth then the magnetic needle of compass is pointed towards the North direction.

This is because the magnetic needle has tendency to attract towards the South pole of magnet and since the Earth has its own magnetic field due to which North pole of earth behaves like South pole of magnet so the magnetic needle is attracted towards the North pole of Earth.

So here magnetic needle is pointed towards North pole on the Earth surface.

Now when magnetic needle is taken to the moon of the Earth then magnetic needle is not showing any direction because at the surface of moon there may not exist any magnetic field due to moon itself so the magnetic needle do not have any force on it.

So magnetic needle shows the direction on surface of Earth not on the surface of moon.