If you take a compass to the Moon, it would not point northwards. It is not because your compass is faulty. A compass shows directions in alignment with the Earth’s magnetic field. We already know that the Moon has a very weak gravitational field. It does not have a strong magnetic field either. To understand this better, let us take a look at how the Earth’s magnetic field is formed.
The core of the Earth is filled with hot liquid iron. This molten iron swirls as our planet rotates, thus producing the Earth’s magnetic field. The Moon’s core is less dense than the Earth. Therefore, the Moon’s core may contain only a little amount of metal; this might not even be heavy iron. On the Moon, the fluid motion of the conducting material is either very less or not present at all. As a result, the Moon has a weak magnetic field compared to that of Earth. It is around one hundredth of the Earth’s magnetic field.
Picture Credit : Google