Non Life Sciences > Geology, Palaeontology & Archaeology

Could the Earth's core be a contained ball of plasma?

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DoctorBeaver:
Here's an article that puts this theory in the context of planetary expansion (which is what the site is about):-

http://www.wincom.net/earthexp/n/owen.htm

I don't have time at the moment to read it thoroughly, but I shall try to do so later.

Jim or Bass - have you come across "Expanded Earth" theories before? If so, what are your views (maybe a new thread?)

Soul Surfer:
It depends a bit what you mean by plasma. If you mean a fluid core that conducts electricity it most definitely has.  If you mean compressed gas with a similar composition to a star it most definitely has not for several reasons.  I will list them.

Firstly, considering the accretion processes that lead to stars and planets to produce sufficient gravity to hold light gases together you need a great deal of mass.  At least as much as a planet like Jupiter or Saturn.

Also the accretion process tends to produce differentiation in which the heavier elements like iron and silicon tend to sink to the centre.  The large amount of heat generated by the accretion process will also tend to melt the protoplanets to help this differentiation process.  It is simply not logical that a core of highly compressed gas could form.

The overall mass and density of the earth is well known. and is totally consistent with this expected structure.  Seismic wave propagation show the liquid core and possibly the solid inner core and this is consistent with the properties of materials measured in laboratories.

There have always been people about who put forward outrageous theories that contradict current accepted models and it can be a way to gain a certain degree of notoriety and money particularly if the theories have other attractive properties  (look up Immanuel Velitovsky's books in the 1950's)  The growth of the internet has greatly expanded the ability of a person to gain publicity in this way.  Occasionally these theories may cast light on current thinking but most often they are not useful and just waste genuine scientist's time and effort contradicting them in precise detail.

JimBob:
But isn't the fluid core the outer core not the core at the center of the earth? Gas Plasma isn't the answer.

The expanding earth theory has been around since the 1960s to counter the new evidence being discovered for continetal drift. See http://en.wikipedia.org/wiki/Expanding_earth_theory
 

Also, The theory of a plasma core has been around since 1979 as the raging debate over the theory of continental drift was beginning to die down. It seems, looking at the material Dr. B. introduced above, that this was a theory postulated to counter continental drift.

Just a few of the objections I have to this theory of an expanding earth due to a plasma core:

1.) It is nearly a 2:1 increase in the size of the earth required to accomplish the present continental configuration. Where did all of this material come from? A much more dense earth would prevent, not allow plasma expansion.

2.) The theory starts off with an earth without oceans. Did we suddenly get bombarded with water out of the celestial ether to create the vast amount of water in the oceans?

3.) India is always attached to Asia in the expanding earth theory, but the Himalayas are composed of rocks deposited in an ocean environment - limestones with corals, sea shells of gastropods, mollusks and many other sea creatures.

4.) The dominant theory to explain most of the events in the plasma theory as presented by http://www.wincom.net/earthexp/n/owen.htm is catastrophism. All of this happened in a few thousand years as the result of a meteor impact creating the Pacific Ocean. The rest of whet was there became th moon.

No, this just doesn't work. Neither does the theory as summarized on the Wikipeidia page.

And the beginning of this theory as suggested in the site Eth mentioned, is the impact of a huge meteor that caused the moon to separate from the earth. That happened 4.5 billion years ago. Why would it not be until 250 Million years ago that the earth started to expand? where was the plasma all the rest of the time?

It just doesn't make sense.

I am sure Soul Surfer could come up with a multitude of other arguments based on plasma theory but that would most likely be a waste of time.

DoctorBeaver:
Ian & Jim - thank you both.

I hadn't heard of the expanded Earth theories before and I can read that site now with a better understanding.

JazzRoc:
Pardon me, but I thought that the Earth's core just had (capitalise this!) to be plasma. That is, an unliquidifiable and unsolidifiable gas-like material mixture of iron, nickel, and many other heavy metals possessing a considerable density, a magnetic field, and just nowhere to go, as a consequence of the incredible pressure of lighter metal mixtures and magma floating over it. The surface of the Sun illuminates us, does it not, with a surface temperature (6,000 deg C) no different from that of the Earth's centre?
I must confess to being intrigued by the theory of the expansion of planetary bodies (not just the Earth) but I think (or hope!) that that is the consequence of our innate tendency to "line things up and ignore the details".
Someone please correct me if I appear to be wrong...

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