The earth's magnetic field is constant?

Question

is it true or false?

Answer 1

In the short term, yes; it ain't gonna change noticeably before you get back from your camping trip, so take that magnetic compass along in case the batteries in your GPS go bad. In the long term, no; depending on where you live, your local magnetic deviation may have changed significantly in your lifetime. Don't rely on the magnetic deviation printed on your grandfather's topographical maps.

The north and south magnetic poles remain fairly stable for about 150,000 years; then they do a complete flip over a period of perhaps 5,000 years. Computer simulations suggest that Earth's magnetic field may behave chaotically during the flip. It may weaken; the poles may wander; there may even be times when there are more than two poles.

Answer 2

False

Answer 3

No, it changes all the time. The magnetic poles, the points at which the earth's magnetic field is perpendicular to the surface, are always on the move, changing by as much as a degree of longitude and latitude in a year. The strength of the field is also variable - it has decayed by 5% over the last 150 years since accurate measurements were first taken. On top of that, it gets buffeted by solar activity - a strong solar wind will distort the shape of our magnetosphere, causing it to flatten more on the side facing the sun, and stretch out on the side facing away.

Furthermore, the Earth's magnetic field inverts completely from time to time ("geomagnetic reversal"). We know this because of sea floor spreading - where two tectonic plates pull apart, new molten rock flows into the gap and solidifies, and when they do any ferric particles in the rock are aligned to the Earth's magnetic field at the time the rock formed. By examining these rocks as they move away from plate boundaries, we have seen that the Earth's magnetic field is sometimes polarized in one direction, sometimes in another. Some people will tell you we are "overdue" for a reversal, but this is impossible to say because there is no clear pattern to them - sometimes we go several million years without one, sometimes we get a dozen reversals in the same period.

Answer 4

false. It changes polarity frequently and we are overdue for another flip.