Crystallisation of the earths core! Is it responsible , as a timer , for magnetic reversal?

[Mike Smith Cosmos]

There is talk of slow rotational movement of earths core ! Is this a clock slowly ticking over millions of years . So that magnetic (North Pole - South Pole ), reversal is controlled from within , rather than without? Possibly caused by crystallisation of molten iron to solid iron?

 

Modern research and speculation is considering the dual nature of the core as it crystallises and produces two very long rotational time periods , may trigger the reversal mechanism . Or be the clock underlying the mechanism.

 

Ref :- link http://www.bbc.co.uk/programmes/b05s3gyv#auto

 

Mike

Edited May 1, 2015 by Mike Smith Cosmos

[Acme]

There is talk of slow rotational movement of earths core ! Is this a clock slowly ticking over millions of years . So that magnetic (North Pole - South Pole ), reversal is controlled from within , rather than without? Possibly caused by crystallisation of molten iron to solid iron?

 

Modern research and speculation is considering the dual nature of the core as it crystallises and produces two very long rotational time periods , may trigger the reversal mechanism . Or be the clock underlying the mechanism.

 

Ref :- link http://www.bbc.co.uk/programmes/b05s3gyv#auto

Thanks for the video Mike. I thoroughly enjoyed it.

 

As to your question about a timer/clock, the answer is no. The field reversals are not regular. As they explained in the video, there have been reversals sometimes on the order of a million or so years, but also periods of no reversals over 100s of million years. Irregularity is not a characteristic of a clock or timer.

Edited May 2, 2015 by Acme

[John Cuthber]

Re "Possibly caused by crystallisation of molten iron to solid iron? "

Nope. The temperature is wrong.

[Mike Smith Cosmos]

Re "Possibly caused by crystallisation of molten iron to solid iron? "

Nope. The temperature is wrong.

Well apparently the temperature at the core is approx 6000 C or K ( don't suppose the few degrees difference, makes a difference) , this 6000 degrees , being similar to surface of the sun. Apparently under the sort of pressures experienced , at the Earth centre then these experts (suggest in speculative mode ) , that solidification ( crystallisation, freezing ) , is possible , and is happening . The detection mechanism being the analysis of the relavent ' S' wave , or 'P' wave , whether trying to see solid or liquid form.

 

Perhaps I have understood it wrong , they appear to be only very new into the research , like right now . ( see above quoted interview . Melvin Bragg with experts) :- http://www.bbc.co.uk/programmes/b05s3gyv#auto

 

ps . In case the program is too long , it's near the end

 

Mike

Edited May 2, 2015 by Mike Smith Cosmos

[pavelcherepan]

Thanks Mike, that was an interesting talk, very enjoyable. As far as your question in the OP is concerned - I don't think crystallisation is responsible, because (as also been said in the video) crystallisation of iron and increase of the size of the inner core occurs pretty much constantly at a rate of fractions of a millimeter a year as a result of general cooling of the planet. If crystallisation was responsible, geomagnetic field should either be reversing constantly or not reversing at all, but that's not something that we're observing. There are some simulations that show that magnetic field is quite unstable and will randomly revert after some time.

 

Also, some points of nit as per BBC4 talk: the notion voiced by one of the guests that rotation of water in a sink is affected by the Coriolis' force is wrong AFAIK. It's mostly due to the shape of sinkhole and whatever residual angular momentum water has from being poured into the sink. When Arwen Deuss was talking about shorter travel times of seismic waves between N-S compared to opposite sides of the equator, no mention was made of different radii in these directions. And in the end when they were talking of how magnetic field is important for habitability of planets and said that planets with no magnetic fields have their atmospheres stripped of by solar wind, for some reason Venus had been forgotten, while it has next to no magnetic field, is closer to the Sun and yet its atmosphere is 90 times larger than Earth's.

[billiards]

When Arwen Deuss was talking about shorter travel times of seismic waves between N-S compared to opposite sides of the equator, no mention was made of different radii in these directions.

 

Yes, you are correct. However, Arwen (and cohort) do make an ellipticity correction to account for this; she just doesn't talk about it on the radio. Probably fair enough given the average level of the audience.

[Mike Smith Cosmos]

The Earth's Core

 

 

The inner core is an extremely dense, solid ball of iron and nickel, the size of the Moon,

 

---[[[. . . while the outer core is a flowing liquid, the size of Mars. . . . ]]] ...

 

Thanks to the magnetic fields produced within the core, life on Earth is possible. The magnetosphere protects the Earth from much of the Sun's radiation and the flow of particles which would otherwise strip away the atmosphere. The precise structure of the core and its properties have been fascinating scientists from the Renaissance. Recent seismographs show the picture is even more complex than we might have imagined, with suggestions that the core is spinning at a different speed and on a different axis from the surface.

 

.

 

Molten outer core ' the size of Mars ! Eeks !

 

Mike

[Robittybob1]

Re "Possibly caused by crystallisation of molten iron to solid iron? "

Nope. The temperature is wrong.

You would need to take pressure into account as well.

[swansont]

The Earth's Core

 

 

The inner core is an extremely dense, solid ball of iron and nickel, the size of the Moon,

 

---[[[. . . while the outer core is a flowing liquid, the size of Mars. . . . ]]] ...

 

Thanks to the magnetic fields produced within the core, life on Earth is possible. The magnetosphere protects the Earth from much of the Sun's radiation and the flow of particles which would otherwise strip away the atmosphere. The precise structure of the core and its properties have been fascinating scientists from the Renaissance. Recent seismographs show the picture is even more complex than we might have imagined, with suggestions that the core is spinning at a different speed and on a different axis from the surface.

!

Moderator Note

That text is taken from http://www.bbc.co.uk/programmes/b05s3gyv

 

Don't pass other sites' words off as your own. This is both a copyright and a plagiarism issue.

 

Do not respond to this modnote

[Mike Smith Cosmos]

 

. The Earth's Core. In Our Time

 

 

+++++{. All comments in post # 7 are directly lifted from, and credited with and to :-

The opening ' Picture ' and ' Title Paragraph' of Melvin Braggs' episode of " In our time ". } +++++

 

This is found in post # 1 . Within the internet link to BBC 4 programme ( In Our Time by Melvyn Bragg. )

 

As such , these comments about the central Core being liquid on its outer parts , and the comments about it being the size of Mars and ' possibly crystallising from the inside out , are comments originating from the ideas of the specialist , researchers , identified in this particular episode of " In our Time " BBC Radio 4 .

 

Link : - http://www.bbc.co.uk/programmes/b05s3gyv#auto

 

Link will show picture of Mars Sized molten outside layer of Inner core.

 

By pressing. ' see more ' . under the opening paragraph , will show statement made in post # 7 above , as well as the names of Specialists who contributed to the ideas and programme .

 

Mike

Edited June 2, 2015 by Mike Smith Cosmos

[Harold Squared]

By whatever means, a reversal of the magnetic field might have dire consequences for our technology, or is this too much to assume?

Edited June 7, 2015 by Harold Squared

[Mike Smith Cosmos]

By whatever means, a reversal of the magnetic field might have dire consequences for our technology, or is this too much to assume?

My guess, and it is only a guess, is that :- when the change in direction to the magnetic field occurs , it will be over sufficient period of time for us to adapt , as it occurs.

 

Mike