2007-01-30 05:46:33 · 3 answers · asked by celeste 1 in Science & Mathematics ➔ Earth Sciences & Geology
It is the reversing of the north and south polarity. Usually it is preceded by a weakening of the magnetic field, and the emergence of multiple poles. You will see the northern lights, (auroras) in places far south of where they are normally seen. It is also thought by some to adversely affect weather since the weakened magnetic field allows more solar radiation to reach the earth. We are definitely in a period of magnetic field weakening to the tune of 10% (measurable) over the last hundred years. Probably has a lot more to do with the so called 'global warming' than any human activity.
2007-01-30 06:05:13 · answer #1 · answered by badabingbob 3 · 0⤊ 0⤋
The magnetic field of the Earth has reversed many times, the last being about 700,000 years ago so we are overdue for another one. The magnetic field has been aligned with the north pole in the south for longer than the current arrangement. The reversals can be seen in the alignment of crystals and minerals in rocks spreading out from mid-oceanic ridges.
The reversals do not seem to be associated with any of the mass extinctions so their affect on life on the planet is likely to be minor.
2007-01-30 16:05:24 · answer #2 · answered by tentofield 7 · 0⤊ 0⤋
I believe it refers to the reversal of the magnetic poles of the Earth, when the magnetic field of the planet changes direction. It happens on a regular, but very long interval. I think the last time it changed was over 7,000 years ago.
2007-01-30 13:55:59 · answer #3 · answered by some_guy_times_50 4 · 0⤊ 0⤋