Reversal of Earth on it's axis?

Question

Qualified scientists only please. I have seen many references and documentaries on the subjects of magnetic pole reversal and regarding past times when the earth actually tilted extremely or flipped over on it's axis so that the southern and northern hemispheres changed places. I have a friend who believes that is purely speculative or outright whacko. But I am fairly certain that I have seen true scientific material somewhere verifying that this has indeed happened in the past and will probably happen again at some point. Is there anyone who can address this who has actual knowledge, not speculation?

Answer 1

Lord is correct about the poles in question and the orientation of a compass needle before and after a pole reversal.

To be more explicit, the supporting evidence for pole reversal was found in the rocks on either side of the mi-ocean ridge. The mid-ocean ridge is a divergent boundary. At that location two of the earth's lithospheric plates are pulling away from each other, thereby thinning the plates.

This thinning allows magma to rise and flow onto the ocean floor as lava. The magnetic minerals in that lava will orient themselves toward the magnetic north pole as would any magnetic substance. When the lava cools and hardens, the orientation of the molecules are locked into place.

Also, the new lava is pushing the seafloor away from the mid-ocean ridge on both sides of the ridge. That seafloor continues to be pushed away and is eventually subducted under a continental plate at a convergent boundary.

When a pole reversal occurs, the orientation of the molecules in the magnetic lava also change creating a record for examination.

As technology advanced, it became possible to obtain samples of the seafloor rocks. When examined, it was discovered that the orientation of the rocks on one side of the mid-ocean ridge were a mirror image of the rocks on the other side.

Not only was this supporting evidence for the theory of sea floor spreading, it also gave a recod of pole reversals in much the same manner that a geologic column reveals information about earth's past.

These reversals happen infrequently-on average every 250,000 years. It's been over 700,000 years since the last reversal, and the next one may be currently underway.

Scientists have been observing changes in the direction of earth's magnetic field which took place recently as well as in the distant past. NASA’s website features a map showing the gradual northward migration of the north magnetic pole in the past century and a half. Since more than double the time interval has elapsed since the last reversal, compared to the time lapse between the previous two pole reversals, some believe we may be overdue for the next north-south flip.

The weakening of earth’s magnetism is one of the factors believed to be predictive of a pole reversal. That magnetic field reversals have occurred in the past is confirmed in the geological record. What is unclear is how precisely the transition occurs, and what happens to life forms at the time of this pole flip.

Answer 2

I think there's some confusion of axes involved here. There's the axis on which we spin, the imaginary line from the true north pole to the true south pole. That never moves relative to the Earth's surface--that is, the planet does wobble slightly, but true north is always on the same spot on the Earth.



The other pole in question is magnetic north and south. That moves around constantly, sometimes wildly, year to year. The Earth's magnetic field does reverse polarity every so often (every quarter million years or so on average), and they think it may be coming due for another flip soon.



When the polarity flips, compasses will point in the opposite direction they do today. The Earth itself won't physically turn over, but compasses made before the flip will read backwards. And other than compasses, you probably wouldn't notice the difference on the ground.

Answer 3

I to have read that the earth has had it's polarity reversed..this has been verified by archaeologists..that have found rocks showing a reverse polarity from time to time ,through the ages..but I to can't find evidence,facts or websites stating this..

Answer 4

yes it happen average of 10 000 years,the proof reverse polarity found in lava rock all around the world-last one was 13 000 years ago we are past due

Answer 5

D) Are recorded in seafloor rocks ... They by possibility left a magnetometer on in a trans-Atlantic flight and recorded te variations. thats how whats up ever found out that the poles actual do opposite themselves.