I have a naive question about flux lines around permanent magnets. If you were do put iron filings around a magnet under a piece a paper, the filings would arrange along the flux lines, with some regions having high magnetic strength, and others that appear to have very little (the spaces between the lines). When I measure the magnetic field of a permanent magnet using a basic magnetometer (like in my Iphone), the field strength appears to increase steadily as I get closer to the magnet. Should the readings not fluctuate up and down as the sensor goes through the flux lines? Why does the permanent magnet appear to have a continuous magnetic field? Is it just due to the sensitivity of the magnetometer?