The average Hackaday reader likely knows, at least in the academic sense, what a magnetic field ... of what the field lines would look like on its electronic paper display. Relative field strength ...

or the magnetic field of a magnet. place the plotting compass near the magnet on a piece of paper mark the direction the compass needle points move the plotting compass to many different positions ...

How the universe got its large magnetic fields has remained ... Where do the weak seed fields come from in the first place? In a paper submitted to The Astrophysical Journal in October ...