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

In summary, 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.
  • #1
momentum
111
0
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 ?
 
Earth sciences news on Phys.org
  • #2
  • #3
Andre said:
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 .
 
  • #4
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 ?
 
  • #5
momentum said:
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."
 
  • #6
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.
 
  • #7
lisab said:
More like, "move away from, slowly."

like the clouds in the sky... drifting slowly.
 
  • #9
runner said:
like the clouds in the sky... drifting slowly.

ahh...beautiful analogy addition ...simple , concise and exact hit ... I liked it ...thanks :)
 
  • #10
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.
 
  • #11
Evo said:
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.
 
  • #12
jim mcnamara said:
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 :)
 
  • #13
So our compasses will one day point south?
 
  • #14
Hi momentum! :smile:
momentum said:
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! :biggrin:

that's drifting!​

"Drifting" is used to describe any really slow movement …

for example "continental drift" is a few cm a year.
 
  • #16
leroyjenkens said:
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.
 
  • #17
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?
 
  • #18
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.
 

1. What is Earth's magnetic field and why is it important?

Earth's magnetic field is a protective shield that surrounds our planet, created by the flow of liquid iron in the outer core. It helps deflect harmful solar radiation and protects our atmosphere and living organisms from its effects.

2. How do scientists know that Earth's magnetic field has reversed in the past?

Scientists can study the alignment of magnetic minerals in rocks to determine the direction and strength of Earth's magnetic field at the time the rock was formed. This has revealed that the magnetic field has reversed multiple times throughout Earth's history.

3. What causes Earth's magnetic field to reverse?

The exact cause of magnetic field reversals is still a subject of ongoing research, but it is believed to be related to changes in the flow of iron in the outer core. These changes can occur due to convection currents, which are influenced by factors such as Earth's rotation and heat flow from the core.

4. How long does it take for Earth's magnetic field to reverse?

The duration of a magnetic field reversal can vary, but it is estimated to take several thousand years. However, the process is not continuous and can involve multiple reversals over a period of tens of thousands of years.

5. What are the potential effects of a magnetic field reversal on Earth?

A magnetic field reversal could potentially weaken or disrupt Earth's magnetic field, leaving us more vulnerable to harmful solar radiation. It could also affect migratory patterns of animals and the accuracy of compasses. However, there is no evidence to suggest that a magnetic field reversal would cause catastrophic effects on Earth or its inhabitants.

Similar threads

Replies
14
Views
2K
Replies
2
Views
7K
  • Quantum Physics
Replies
12
Views
1K
Replies
15
Views
1K
Replies
18
Views
4K
  • Astronomy and Astrophysics
Replies
30
Views
5K
Replies
14
Views
1K
  • Astronomy and Astrophysics
Replies
5
Views
1K
Replies
5
Views
854
  • Introductory Physics Homework Help
Replies
1
Views
887
Back
Top