Earth's Magnetic Field Weakening

[davenn]

The sun flips polarity about every 11 years. Its cycle changes the amount of solar activity from little to a peak around reversal time. The next sun reversal will occur in 2012.

Not quite right :) ... you are getting a bit confused, The 11 (approx) year cycle always changes polarity at solar minimum which we have just had and are slowly clawing our way out of. Solar max is at 2012-2013 approx

The sun flips its magnetic field every 11 years. This is a common event although the solar flare activity heightens.
http://solarscience.msfc.nasa.gov/predict.shtml

Also not quite right... You need to remember that there are 2 magnetic cycles happening in the sun.
1) ... the reversal of the sunspot magnetic fields 11 years and
2) the reversal of the actual solar magnetic field which is 22 yrs.

That article you cited is referring to the sunspot cycle ( ~ 11 yrs) I say ~ 11 yrs because it isn't a constant length of time. This last cycle transition from cyc23 to cyc24 produced one of the longest minimum period for a 100+ years

cheers
Dave

 

[davenn]

Originally Posted by ZaUS22
I read that by studying lava samples it was determined the Earth’s magnetic field has reversed about 18,000 times in 20 million years.

Where did you read that? This sounds very, very high. That's every 1100 years.

Agreed, Vanadium, in my Geology studies at uni, I would suggest more likely 8times in 20 million yrs.
Looking through the records the flipping is very random in the time periods between flips.

It was the early work on continental drift and seafloor spreading that lead researchers to tow magnetometers behind ships

Dave

just reading through my notes... Cox and Dalrymple who pioneered magnetic flip studies (on land) with their initial work on lava deposits in the Owens Valley, California. They were, after a few years (by 1966), able to confirm 9 reversals in the last 4 million years
It was Vine and Matthews of Cambridge Uni (England) that finally deciphered that the data was showing and were able to conclusively prove seafloor spreading

 

[rbluesky]

I am not a scientist, so please forgive my clumsiness with the following :

Is it true that the Earth has a "hole" in its magnetic field near Brazil?

Is it true that there has been a rapid increase in the amount of nutrenos in the Earth's atmosphere?

Is it true that the Earth's magnetic field is not only weakening at an increasing rate but also "true North " has shifted 60 miles in the past year?

IF ALL of these statements are true then, well, doesn't this fall into the Mayans end of days ?

"... at last I have the answer! But what was the question?"

Thank-you for reading this!
I am forever amazed at the wonders of the universe.
Rita

 

[qraal]

I am not a scientist, so please forgive my clumsiness with the following :

Is it true that the Earth has a "hole" in its magnetic field near Brazil?

The South Atlantic Anomaly could be called a hole.

Is it true that there has been a rapid increase in the amount of nutrenos in the Earth's atmosphere?

No. Did you get that from "2012" the movie? Total rubbish.

Is it true that the Earth's magnetic field is not only weakening at an increasing rate but also "true North " has shifted 60 miles in the past year?

The magnetic pole shifts around quite a bit, but "True North" is the direction of Earth's rotational axis, which most definitely hasn't moved. You'd know about it if it had.

IF ALL of these statements are true then, well, doesn't this fall into the Mayans end of days ?

"... at last I have the answer! But what was the question?"

Thank-you for reading this!
I am forever amazed at the wonders of the universe.
Rita

The "Mayan End of Days" has nothing to do with the end of the world. It's just when the Mayan calendar resets. Start of a new epoch, in one time-keeping system. It corresponds to nothing magical or catastrophic, aside from the perfervid imaginings of bored/gullible non-Mayans. The Maya are still around and resent the misuse of their calendar.

 

[cmb]

YU55 - I have gone to the trouble of calling your bluff here, so please do explain your hypotherflappery with respect to the following data:

http://i1177.photobucket.com/albums/x345/chris20055/ice_sheets_versus_geomag.jpg

Please do explain the correlations, for my education...

 

[cmb]

I'll take your graphic as correct. I don't know where that data comes from, I don't claim to know much about mag field reversals.

So plotting it against the ice sheet graphic... I still don't see the correlation you are implying:

http://i1177.photobucket.com/albums/x345/chris20055/ice_sheets_recent_geomag.jpg

 

[Evo]

There hasn't been a reversal for ~780,000 years.

Thread locked pending moderation and moved to Earth sciences.

Also thanks to Andre, the Gothenberg "flip has indeed been debunked, it was a bad sample. It also doesn't coincide with any extinction.

The Gothenburg "Flip"
In the case of the Gothenburg "flip," which Hancock (1995) misidentified as a "magnetic reversal, FOG again provided a poorly researched analysis. The still unproved Gothenburg "flip," if real, was a rapid and brief change of magnetic field that occurred about 12,350 BP. It was not a real magnetic reversal. The last true magnetic reversal occurred 730,000 years in the change from the reverse polarity of the Matuyama Magnetic Epoch to the normal polarity of the Brunhes Magnetic Epoch. The Gothenburg "flip," as proposed by Morner (1971) and reported by Anonymous (1972), is more properly called a "magnetic excursion" because the Earth magnetic field did not reverse itself permanently but briefly changed without complete reversal over the period of a few years. For this event to represent Earth crustal displacement, the Earth's crust at about 12,350 BP would have to shift 180 degrees one direction and shift another 180 degrees back to its exact original position within the space of a few years. The timing of the Gothenburg "flip" fails to match any proposed Earth shift by either Hapgood (1970) or Flem-Ath (1997) in either timing or amount of predicted shift. Also, the validity of the Gothenburg excursion has been challenged by a number of studies which repeated have failed to detect its presence in a number of paleomagnetic records that cover 12,350 BP. At this time there is considerable question that the Gothenburg excursion even occurred and, in fact, the result of soft sediment deformation (Jacob 1994:103-107).

continued...

http://www.intersurf.com/~chalcedony/FOG10b.html

See existing thread https://www.physicsforums.com/showthread.php?t=525126