How can the magnetic field around a permanent magnet be determined?

A compass needle is a permanent magnet, which itself reacts to the permanent magnet in the earth's axis. Unfortunately, the fields of permanent magnets are very hard to calculate, and require an understanding of complex ferromagnetic phenomena, belonging as much to atomic theory as to electromagnetism.

the first step is making objective observations.

they have to be based on a certain event and can be confirmed by others if it is right or not.

okay i have so many questions. but the big one here is: um wt..f is this mess? ?