Earth’s magnetic field has reversed a number of times in its history


by momentum
Tags: earth’s, field, history, magnetic, number, reversed, times
momentum
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#1
Jan5-10, 09:01 AM
P: 32
please see this English text ...


The Earth’s magnetic field has reversed a number of times in its history. Before the poles actually flip, the magnetic field weakens and the magnetic poles drift away from “true” north and south.


>>>magnetic poles drift away from “true” north and south.

what does 'drift away' means ? I don't understand the meaning of 'drift away' ...I need english help ..... any native speaker or someone knows better english ?


N.B: is not the north pole of earth's magnetic field a little distant away from geographic north pole ?
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Andre
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#2
Jan5-10, 09:24 AM
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Have you tried http://translate.google.com/#

drift away:

التغرب
отклонение
allunyar-se
游離

etc, etc
momentum
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#3
Jan5-10, 09:35 AM
P: 32
Quote Quote by Andre View Post
Have you tried http://translate.google.com/#

drift away:

التغرب
отклонение
allunyar-se
游離

etc, etc
unfortunately my language is not listed there. ...so I did english to english conversion.

but anyway , I had a feel that it means dragging away , throwing away .

momentum
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#4
Jan5-10, 09:45 AM
P: 32

Earth’s magnetic field has reversed a number of times in its history


I also read

On average, the
magnetic north and south poles flip about
once every 200,000 years. The last time the
poles flipped was 780,000 years ago.
Therefore, the poles are in the process of
reversing.
really ? is it dangerous for human race ? what is the environmental effect for this if truly pole flips this way i.e south pole becomes north pole and north pole becomes south pole ?
lisab
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#5
Jan5-10, 09:46 AM
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Quote Quote by momentum View Post
unfortunately my language is not listed there. ...so I did english to english conversion.

but anyway , I had a feel that it means dragging away , throwing away .
More like, "move away from, slowly."
Andre
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#6
Jan5-10, 09:47 AM
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drift away -

wander away, meander away, going aimlessly in any direction, to stray away, deviate away.

Discussion about Earth magnetic fields should go in the Earth forum.
runner
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#7
Jan5-10, 09:50 AM
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Quote Quote by lisab View Post
More like, "move away from, slowly."
like the clouds in the sky............ drifting slowly.
Evo
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#8
Jan5-10, 09:52 AM
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I don't know how good your English is, but here is transcript of a show about magnetic pole reversal in laymen's terms.

A video showing how it would work.

http://www.pbs.org/wgbh/nova/magnetic/reversals.html

You can click on "transcript" to read the program.

http://www.pbs.org/wgbh/nova/magnetic/
momentum
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#9
Jan5-10, 09:55 AM
P: 32
Quote Quote by runner View Post
like the clouds in the sky............ drifting slowly.
ahh...beautiful analogy addition ...simple , concise and exact hit ... I liked it ...thanks :)
jim mcnamara
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#10
Jan5-10, 09:57 AM
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If you note the fossil record: periodic mass extinctions every 200,000 years (on average) do not exist. It seems reasonable to assert that a "magnetic pole flip" is not an event that devastates all living things.

Mass extinctions occurred on a far longer time scale than every 200,000 years. I'm defining mass extinction as an event that results in the extinction of 50% or more of the species living at the time. The last one of these was at the end of the Cretaceous, ~65 million years ago.
momentum
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#11
Jan5-10, 09:59 AM
P: 32
Quote Quote by Evo View Post
I don't know how good your English is, but here is transcript of a show about magnetic pole reversal in laymen's terms.

A video showing how it would work.

http://www.pbs.org/wgbh/nova/magnetic/reversals.html

You can click on "transcript" to read the program.

http://www.pbs.org/wgbh/nova/magnetic/
thanks for the links .

you know I just need literal meaning ... no engineering stuff ....no complex mechanism needed.....just simple meaning in simple English :)

I appreciate for the effort . And thanks for sharing your valuable time.
momentum
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#12
Jan5-10, 10:03 AM
P: 32
Quote Quote by jim mcnamara View Post
It seems reasonable to assert that a "magnetic pole flip" is not an event that devastates all living things.
he he ... good good .... no apocalypse to come ... no 2012 kind of things :)
leroyjenkens
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#13
Jan5-10, 10:10 AM
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So our compasses will one day point south?
tiny-tim
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#14
Jan5-10, 05:17 PM
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Hi momentum!
Quote Quote by momentum View Post
what does 'drift away' means ? I don't understand the meaning of 'drift away' ...I need english help ..... any native speaker or someone knows better english ?
"drift away" means what a boat does when it has no power (no sails, no engine, no oars), but it isn't tied up …

if you forget to tie the boat to the jetty while you go off to get an ice-cream, you'll come back to find the boat moving very slowly away … and you can't stop it!
that's drifting!
"Drifting" is used to describe any really slow movement …

for example "continental drift" is a few cm a year.
Evo
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#15
Jan5-10, 08:47 PM
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There is a major weakening in the magnetic field called the South Atlantic Anomaly.

http://heasarc.gsfc.nasa.gov/docs/ro...splay/saa.html

There was a thread started about it here http://www.physicsforums.com/showthread.php?t=293270

Ok, this is wikipedia, but it does sum it up in laymen's terms.

http://en.wikipedia.org/wiki/South_Atlantic_Anomaly
russ_watters
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#16
Jan5-10, 10:03 PM
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Quote Quote by leroyjenkens View Post
So our compasses will one day point south?
Yes, but note that if you are near the geographic north pole, your compass already points south!

The magnetic north pole is not at the geographic north pole.
halfbakedi420
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#17
Jan19-11, 10:41 PM
P: 1
300,000 years is what i saw on history channel today. they use the polarity in the rock formed on the ocean floor to determine which direction was....well....north per say...they didnt say when the last one was, but if its 200, or 300 thousand, and its been 700 thousand years...what gives here?
Studiot
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#18
Jan20-11, 05:41 AM
P: 5,462
Hello, momentum, I note that English is not your first language.

You might like to know that the word 'drift' has two nearly opposite meanings.

The meaning here is

'move in a casual or aimless manner'

drift into sleep
the leaves drifting about in the road

but drift is also used in the sense of driven (from drive) where something is directed by an outside force or agency.

a snow drift is a pile of snow collected (driven) by the wind
get my drift = the aim or purpose of a thought


There are a significant number of words in English that have more than one meaning. It can be quite confusing if some of these meanings are also opposite.


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