ocr: Why is the Earth a magnet? Although no one knows for certain, some scientists think the Earth's magnetism occurs as molten rock at the Earth's core moves around. The motion isn't in line with the Earth's geographical North and South Poles, and so the magnetic North and South Poles are slighdy out ofline too. The difference between magnetic north and true north is called the "angle of declination." This varies with your location on the planet. It also changes over time, as the motion of molten rock inside the Earth alters. About 1 million years ago, the Earth's magnetism was completely reversed ...
(.png)
