This was one of my more satisfying essays. Several years ago I gave some thought to what it meant for the earth to be considered a magnet. More recently in 2012 an article in the magazine BirdWatching brought it all back when I saw its diagram of the earth as a magnet for guiding migratory birds. Knowing that magnets have north and south poles, where should we expect to find the earth’s north and south magnetic poles? See Earth as Magnet.
Update (2/28/2025) Even Experts Slip Up
In an otherwise engaging post with video on the possibility of the earth’s magnetic field flipping and what the consequences would be, Sabine Hossenfelder showed images of the earth and its magnetic field lines of force with a north-south magnet superimposed. Alas it showed the north magnetic pole erroneously oriented toward the north geographic pole. I suspect, however, that she may have done this on purpose so as not to distract the uninitiated.
I skimmed some of the comments to her video and it was not until the 38th comment that someone noticed the error:
@mdjurfeldt
The animation showing a magnet inside Earth which flips is backwards. We actually currently have the magnetic southpole in the north. So, if the field flips, the magnetic northpole will move “home”.
Before Flip (3:16)
After Flip (3:19)
