how long ago was the last time earth's magnetic field reversed
Geomagnetic reversal The time spans of chrons are randomly distributed with most being between 0.1 and 1 million years[citation needed] with an average of 450,000 years. Most reversals are estimated to take between 1,000 and 10,000 years. The latest one, the Brunhes–Matuyama reversal, occurred 780,000 years ago, and may have happened very quickly, within a human lifetime.[1]
North Magnetic Pole The North Magnetic Pole moves over time due to magnetic changes in the Earth's core.[1] In 2001, it was determined by the Geological Survey of Canada to lie west of Ellesmere Island in northern Canada at 81°18′N 110°48′W﻿ / ﻿81.3°N 110.8°W﻿ / 81.3; -110.8﻿ (Magnetic North Pole 2001). It was situated at 83°06′N 117°48′W﻿ / ﻿83.1°N 117.8°W﻿ / 83.1; -117.8﻿ (Magnetic North Pole 2005 est) in 2005. In 2009, while still situated within the Canadian Arctic territorial claim at 84°54′N 131°00′W﻿ / ﻿84.9°N 131.0°W﻿ / 84.9; -131.0﻿ (Magnetic North Pole 2009),[2] it was moving toward Russia at between 55 and 60 kilometres (34 and 37 mi) per year.[3] As of 2017, the pole is projected to have moved beyond the Canadian Arctic territorial claim to 86°30′N 172°36′W﻿ / ﻿86.5°N 172.6°W﻿ / 86.5; -172.6﻿ (Magnetic North Pole 2017 est).[2]