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The Earth's Core

rynner2

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A new theory says that the centre of the Earth is actually a huge nuclear reactor.

The idea seems to make sense, and it could also explain why the Earth's magnetic poles 'flip' every few thousand years.

(Better not tell CND or other anti-nuclear types, though!)
 
Hmm !

Could they not just pop a Giger counter down the 7.5 mile hole they commented on and see if the radiation tat far down is worthy of comment. I know it is a tiny hole on the scale of things but if the radiation is higher at 7mi then it is at 5 mi then they could be onto something.

then again I guess the chance of anything significant at theat depth is hardly gonna be likely

So ignore me (too much red wine)
 
Rather appropriate that my email notifications tonight from FT had one about "Underground", and beneath that "The Earth's Core"...!
 
Some quick calculations. Assuming that the radiation from the earth's core obeys a 1/r^2 law, and that the contribution from extraterrestrial sources is tiny, then we find that the intensity of radiation at a depth of 10 km is going to be ~0.3% greater than that at the surface.

However:
a) the radiation from a putative reactor at the core is unlikely to obey the 1/r^2 law. Scattering and absorption phenomena will scupper that idea. (Lots and lots of rock to interact with.) In addition, un-bound neutrons (i.e. those emitted by a nuclear reaction) have a half-life of ~10 mins (if I remember correctly), so most of those will have decayed into other "stuff".
b) a significant source of radiation at the earth's surface is from extraterrestrial sources. (Ye olde cosmic rays.)

But, the previous estimate probably gives a rough order of magnitude estimate as to the maximum change in the radiation intensity that might be observed.:)
 
A new theory says that the centre of the Earth is actually a huge nuclear reactor.
So, it's not a naked singularity, or a mini-blackhole driving everything then? Oh.
 
Fortis said:
Some quick calculations. .....................

In english I gather that you said that we can not yet dig deep enough to measure with sufficient accuracy in order to prove or disprove this theory.
 
When a bit of lead and a few yards of concrete are considered enough protection from a Nuclear Power Station, I guess several thousand miles of rock and mantle would make it nearly impossible to detect the radiation from the Earth's core.

Presumably now the idea is out in the open various experts will think on't and come up with more subtle ways to prove or disprove this theory.

But it surprises me that no-one seems to have suggested this before - it's long been known that uranium is the heaviest element, so would have settled to the centre of the planet, and there has even been one case of a natural reactor than ran in a uranium deposit somewhere in Africa, I think.
 
Actually, rynner, J Marvin Herndon published "Nuclear Fission Reactors as Energy Sources for the Giant Outer Planets" in the journal Naturwissenschaften in 1992. The silence was deafening.

The case you speak of was in Gabon, Africa. In 1972 scientists found fission-produced isotopes of neodymium and samarium in a seam of uranium. No one said much about that, either.

God, I love my subscription to "Discover"!
 
nife

I used to enjoy 'Call MyBluff' and learned many new words from it.
One was 'nife', pronounced 'niffee'. This is apparently what the centre of the earth is composed of: nickel and iron, the word being a combination of their abbreviations.

So it should really be 'NiFe', I suppose. Hmmm.
 
Minor Drag said:
Actually, rynner, J Marvin Herndon published "Nuclear Fission Reactors as Energy Sources for the Giant Outer Planets" in the journal Naturwissenschaften in 1992. The silence was deafening.

The case you speak of was in Gabon, Africa. In 1972 scientists found fission-produced isotopes of neodymium and samarium in a seam of uranium. No one said much about that, either.

God, I love my subscription to "Discover"!

The reactor is certainly well known among the nuclear engineering community. In fact, I've even heard it get used in an attempt to demonstrate that nuclear power is safer than people think, because a reactor was operating with no safety systems, for X number of years with no lasting impact on the environment. Not convinced that this reasoning holds, though.;)
 
Hmmm.... if I may just add my own lack of knowledge here (never stopped me before!).

Uranium would surely be extremely rare in the universe, compared to say iron or aluminium, because it is so heavy. Assuming this is correct, than there simply wouldn't be enough of this element to account for all the planets (and moons, asteroids, etc) in our solar system, let alone elsewhere. This doesn't mean of course that some planets don't have uranium cores, but I'm not convinced that Earth is one of them.

I seem to recall from Earth Sciences studies that the Earth's inner core is believed to be either solid iron or a mixture of iron & nickel - this is inferred from the behaviour of seismic waves (S & P waves) and also from studies of volcanic rocks (some of which originated in the inner core). Evidence from meterorites, which may be the failed remains of planet formation, also bears out this theory.

A liquid iron outer core sloshing around above this solid ball accounts for the Earth's magnetic fields.

I say "fields" rather than "field" because there is more than one, and the interference patterns between these different fields is sufficient to explain the shifting of the magnetic poles over time, and even their occasional apparent complete disappearence and "flip".

Having said all that, there's a lot of "infers" and "may bes" in the accepted version and any new theory that challenges the status quo is fine by me. If it can answer puzzles not addressed by the existing theories then it will be accepted, grudgingly, in time... possibly not in our lifetime, but eventually.

Jane.
 
Someone once explained to me, when I was at University, that Geology is a very faddish science, and that theories about planetary formation and the internal structure of the Earth tend to change on a regular basis. This is largely because of the problems mentioned: that we haven't been able to look at it directly. That being said, I see a few problems with the theory as stated.

1. A ball of Uranium 5 miles wide is a lot of Uranium. As mentioned, Uranium is only formed as a by-product of supernovae (on current theories). That's a lot of supernovae.

2. The other planets mentioned (IE: those with the "unexplained" energy output) are gas giants, not terrestial planets. Gas giants could be expected to have a radically different structure (as is evidenced by the size of their atmospheres) to a planet like the Earth. So, even if it were true for gas giants (which I'm not convinced, see point one above), that's not enough to make it likely for Earth.

3. While we haven't been able to drill down terribly far into the core, we have been able to probe it with radar. The last I heard, this had given geologists a fairly good idea of what it looks like, if not exactly what it's made of.

4. We know how dense the Earth is (we know how much it weighs, and we know how big it is). Surely the difference between a large lump of Uranium at the core and a large lump of nickel/iron would be noticeable?

If we wanted to check, couldn't we just ask the people at the bottom of the hole the Russians drilled into Hell? Surely someone down there would have an idea? (Unless of course they're too busy being tortured.)
 
But surely the earth's hollow?:p

As a person with a totally non-scientific brain, might it not be possible that there is a completely new element or elements at the earth's core? I'm probably showing my abject ignorance here. Have all the elements that exist been discovered? How do we know whether or not they've all been discovered?

Carole
 
anome said:
4. We know how dense the Earth is (we know how much it weighs, and we know how big it is). Surely the difference between a large lump of Uranium at the core and a large lump of nickel/iron would be noticeable?
As I see it, it's not an either/or issue -

the inner core could be a smallish lump of uranium (but big enough to produce fission reactions) surrounded by a Nife core.
 
When I took geology A level ( 20 years ago ! :eek!!!!: ) I remember being taught the Earth's inner core was a reactor and the temperature of the interior of the Earth was actually rising due to these reactions . I think we were taught this to disprove the long held theory that the Earth was originally molten and was slowly cooling down .
As for natural radioactivity , I live in an area so naturally radioactive the houses need special vents built into them to release it ! All payed for by the government .
 
anome said:
4. We know how dense the Earth is (we know how much it weighs, and we know how big it is). Surely the difference between a large lump of Uranium at the core and a large lump of nickel/iron would be noticeable?

OK - for those good at physics, I am baffled by the statement above. How the hell did we manage to weigh the Earth ?

Is there a foolproof way to do it or in a few years time will New Scientist (or for that matter FT) run an article titled "Earth much lighter/heavier than previously thought".
 
Chriswsm said:
OK - for those good at physics, I am baffled by the statement above. How the hell did we manage to weigh the Earth ?

Is there a foolproof way to do it or in a few years time will New Scientist (or for that matter FT) run an article titled "Earth much lighter/heavier than previously thought".

Here is a basic start

http://www.earthsky.com/1999/es991027.html

will see if I can find more .
 
carole said:
But surely the earth's hollow?

Of course it is, but we have to pretend it's solid (and liquid and so on) to make the equations come out right.

ibid
As a person with a totally non-scientific brain, might it not be possible that there is a completely new element or elements at the earth's core? I'm probably showing my abject ignorance here. Have all the elements that exist been discovered? How do we know whether or not they've all been discovered?

I'm going to try and answer this for you, and I hope I don't screw it up. Let me know if I get too technical, or skim something that might look important, or fail miserably in some other way.

We know that all elements lighter than an atomic number of about 118 have been discovered. (Go to the Periodic Table on the Web. )We know this because an atom can't have a fractional atomic number.
(Atomic number is the number of protons in the nucleus, and, to the best of our knowledge, you can't have a fractional proton in an atomic nucleus. If you could have a fractional atomic number, then everything we know about how atoms work is out the window.)

Thus we can say, with a reasonable level of confidence, that there are no gaps in the Periodic Table as it stands. What people are still looking at, and where we might find new elements, is at the top of the table. It is possible that much larger atoms can still be found, and there are theories that some of them (around the 120 mark or so) may actually be stable. Are any of these at the Earth's core? Possibly, but if there in any large quantities (such as a lump 5 miles across), they will cause an even greater discrepency in the mass of the Earth than Uranium would.

In short, the answer is yes, there may be, but I don't see that there would be too many of them. I could be wrong, though.
 
Marion said:
Here is a basic start

Snipped...........

DB: The most reliable method for "weighing" a planet is to observe its moons. Those observations let you use a mathematical relationship between the distance of a moon from its planet -- how long it takes the moon to orbit the planet -- and the planet's mass. This relationship is known as Kepler's Law. It was discovered several centuries ago -- and has been used to find masses for most of the planets in our solar system

End of Snip.........



will see if I can find more .

Surely for Kelper's Law (accurate as any 'Several Centuries old' law can be) to work we would have to know the weight of the moon in order to establish the relationship with the planet.

Sounds like Guesswork is in use here somewhere.

What if the moon is lighter than we thought ? Or do we measure the moon by the effect imposed on it by the planet - etc etc

:confused: Physics is Pretty complex for someone who only got as far as A'Lvl Human Bio (grade A).
 
Strictly speaking, yes, you do need the mass of the moon too. But in practice most moons are miniscule compared to their planet and as the figure used in the calculations is the sum of the two masses it only makes a tiny difference if the moon's weight is ignored.

In the case of Earth and Moon, we can get their masses from space probe orbits. The Moon is about the biggest in the solar system in respect to its primary, but it is still only 1 / 81 of the Earth's mass, so even ignoring its mass we could get a good 'ball park' figure for the Earth's mass (and using sensible estimates for the Moon's mass would give even more accurate figures).

Any good scientific measurement comes with an estimate of the likely errors, eg as so many tonnes plus or minus 3%, or whatever. (There are precise methods for calculating the error limits.)
 
To be honest I thought it was a big lump or iron which is pretty simple ;)

Earth's core 'simpler than thought'

Scientists working on efforts to understand the Earth's centre have made a surprising discovery: the iron core is actually much simpler than they had assumed.

Researchers at the US Lawrence Livermore Laboratory who have been studying how the enormous pressure inside the planet affects the iron believe there is only one form of atomic structure to the metal.

For the past 20 years, it has been assumed there were at least two.

The scientists are hopeful that by cracking the structure of the core, they can understand better the temperature and pressure there. They have already established the core starts to melt at a lower pressure than previously thought.

Their work has recently been published in the journal Nature.

"It makes the picture a whole lot simpler," Dr Neil Holmes, one of the scientists who worked on the project, told BBC World Service's Science In Action programme.

"It allows us further to focus our efforts... determining the temperature and the other properties of iron."

Huge pressures

The Earth's core is important because it generates the planet's electromagnetic field - which seems to be weakening.

This is already having consequences in space, creating glitches in satellites that rely on the field to protect them from solar and other space radiation.

Furthermore, scientists are keen to find out if the Earth's magnetic poles are about to "flip" - with magnetic North becoming South, and vice versa. It has happened many times before in Earth history.

Dr Holmes said the key to the experiment was recreating conditions that were as close as possible to those that really existed at the centre of the planet.

"We have a large gun which is 20 metres long, which fires flat, iron-faced projectiles into an iron target, making a shockwave," he said.

"That shockwave only lasts for less than a millionth of a second, but during that time we can make conditions that are up to and even exceeding the pressures at the centre of the Earth."

Specifically, what the scientists have found is that the iron adopts a crystalline structure, like a diamond, in the Earth's core.

The Californians are not the only researchers interested in what is effectively a massive dynamo at the centre of the planet driving the geomagnetic field.

Scientists in Riga at the Institute of Physics at the University of Latvia are continuing to work on a much more physical mock-up of the core.

Their model consists of two concentric steel cylinders, three metres high and 80 centimetres in diameter, filled with molten sodium.

A propeller drives the sodium down through the inner cylinder in a helical flow.

The metal returns up the outer cylinder, and electric currents create a magnetic field.

"Sodium has - by a factor of 50 - better electro-conductivity," the University's Dr Agris Gailetis told Science In Action. "Sodium is moving 10,000 times faster.

"But of course our system is much, much smaller... but altogether, these factors are making our experiment not very different from conditions inside the Earth."

'Turbulent regime'

However, bizarrely, the oscillations that the Riga experiment have produced have been found to be more like the regular 22-year-variations in the Sun, rather than the random ones in the Earth.

The reality of the core remains far more complex than concentric cylinders. The flow there is probably turbulent and chaotic.

"The Riga experiment didn't, per se, undergo reversal," said Dr Andy Jackson, who specialises in computer models at Leeds University in the UK.

"But it does generate a magnetic field which is oscillatory - but it's oscillatory in a very regular sense, whereas the Earth is more of a random process."

Dr Jackson outlined the way that such experimental geophysics helps us understand our planet.

"In the last decade we've made great advances in using numerical simulations to understand planetary magnetic field generation," he said. "But there are some real drawbacks with these computations.

"For example, it's almost impossible for us to model turbulent flow. There's a place for the experiments to try to fill in the gap that's left by the numerical simulations.

"The experiments really can reproduce this turbulent regime that's so important in the core."
Story from BBC NEWS:
http://news.bbc.co.uk/go/pr/fr/-/2/hi/science/nature/3433661.stm

Published: 2004/01/28 14:19:41 GMT

© BBC MMIV
 
About time this thread was updated!

New ideas for how Earth core formed
By Simon Redfern, Science reporter, BBC News

Experiments on samples of iron and rock held at immense pressures have led to new ideas of how Earth's core formed.
Scientists from Stanford University have shown that iron metal will flow through rocks 1,000km beneath our feet.
Using sophisticated X-ray imaging, they watched molten metal moving through rocks, squeezed to huge pressures between the tips of pairs of diamonds.
Their results suggest that Earth's core did not form in a single step, but grew in a complicated sequence over time.

The depths of Earth are complex and multi-layered.
At the surface, the rocks forming the foundations of our cities, the stones that we build our lives upon, also provide the raw materials for society - metals, fuel, water and nutrients.
These are no more than a thin geological veneer on the planet. In many respects, the deep Earth remains as much of a mystery as Jupiter or Mars.

But new research in the journal Nature Geosciences gives new clues about how Earth may have taken shape and built its core.
A group of scientists, led by Stanford's Prof Wendy Mao, have shown how metallic iron may be squeezed out of rocky silicates more than 1,000km beneath the surface to form a metallic core.

If you were to follow Jules Verne on a journey to the centre of the Earth, you would find a chemistry dominated by just three elements, until you got almost half the way to the centre - that's the first 3,000km of your journey.
Oxygen, silicon and magnesium (plus a little bit of iron) make up more than 90% of Earth's blanketing "ceramic" mantle.

Electrically and thermally insulating, the mantle is like a rock-wool blanket around the core. The minerals of the mantle are the stony part of the planet. But as you delve deeper on this "thought field trip", things suddenly and drastically change.

With more than half your journey ahead of you, you cross a boundary from the stony mantle into the metallic core. It is initially liquid in its upper stretches, and then solid right the way to the centre of the Earth.
The chemistry changes too, with iron forming almost all of the core, segregated into Earth's dense inner sphere.

The boundary between the metallic core and rocky mantle is a place of extremes. Physically, Earth's metallic liquid outer core is as different to the rocky mantle that overlies it as the seas are from the ocean floor here near Earth's surface.

One might (just about) imagine an inverted world of storms and currents of flowing red-hot metal in the molten outer core, pulsing through channels and inverted "ocean" floors at the base of the mantle.
The flowing of metal in the outer part of the core gives Earth its magnetic field, protects us from bombarding solar storms, and allows life to thrive
.

How Earth's core came about has puzzled Earth Scientists for many years. Experiments on mixtures of silicate minerals and iron, cooked up in the laboratory, show that iron sits in tiny isolated lumps within the rock, remaining trapped and pinned at the junctions between the mineral grains.

This observation has led to the view that iron only segregates very early in the life of the planet, when the upper part of the rocky mantle was in fact super-hot and molten.
It is thought that droplets of iron rained down through the red-hot magma ocean to settle at its base, resting on the solid deeper mantle, then sinking as large "diapirs" driven by gravity through the solid mantle to eventually form a core.

The paper by Crystal Shi and Wendy Mao begins to paint a different picture.
"We know that Earth today has a core and a mantle that are differentiated. With improving technology, we can look at different mechanisms of how this came to be in a new light," said Prof Mao.

Using intense X-rays to probe samples held at extreme pressure and temperature squeezed between the tips of diamond crystals, the researchers find that when pressure increases deep into the mantle, iron liquid begins to wet the surfaces of the silicate mineral grains.
This means that threads of iron can join up and begin to flow in rivulets through the solid mantle - a process called percolation.

It also means that iron can begin to segregate if the rocks are deep enough, even when the mantle is not a molten magma ocean.
"In order for percolation to be efficient, the molten iron needs to be able to form continuous channels through the solid," Prof Mao explained.

"Scientists had said this theory wasn't possible, but now we're saying - under certain conditions that we know exist in the planet - it could happen. So, this brings back another possibility for how the core might have formed."

Commenting on the results, Geoffrey Bromiley, of the University of Edinburgh, UK, who was not involved in the study, told the BBC: "This new data suggests that we cannot assume that core formation is a simple, single-stage event. Core formation was a complex, multi-stage process that must have had an equally complex influence on the subsequent chemistry of the Earth.

"Their deep percolation model implies that early core formation can only be initiated in large planets. As a result, the chemistry of the Earth may have been 'reset' by core formation in a markedly different way from smaller planets and asteroids.
"As such, we might not be able to use geochemical data from meteorites to constrain the bulk composition of the Earth. This is currently an important assumption pervading Earth Science."

The results were reliant on recent advances in 3D imaging of minuscule samples using powerful synchrotron electron accelerators that generate intense beams of X-rays.
Similar to medical imaging, these sorts of experiments are revealing the nanoscale properties of minerals and melts. But they are also leading to new understanding of how huge objects like planets form and evolve.

Dr Bromiley and his colleagues are now investigating the influence of other factors, like the deformation that asteroids and other bodies might have experienced on their chaotic pathways through the early Solar System, on their formation.
He added: "The challenge now lies in finding a way to model the numerous processes of core formation to understand their timing and subsequent influence on the chemistry of not just the Earth, but also the other rocky bodies of the inner Solar System.
"We are increasingly observing metallic cores in bodies much smaller than the Earth. What process might have aided core formation in bodies that were never large enough to permit percolation of core forming melts at great depths?"

http://www.bbc.co.uk/news/science-environment-24454138
 
It's a pity Doug McClure isn't around anymore, we could have asked him.
 
But maybe not so simple...
Iron 'jet stream' detected in Earth's outer core
By Jonathan Amos BBC Science Correspondent, San Francisco
19 December 2016

Scientists say they have identified a remarkable new feature in Earth’s molten outer core.
They describe it as a kind of "jet stream" - a fast-flowing river of liquid iron that is surging westwards under Alaska and Siberia.

The moving mass of metal has been inferred from measurements made by Europe’s Swarm satellites.
This trio of spacecraft are currently mapping Earth's magnetic field to try to understand its fundamental workings.
The scientists say the jet is the best explanation for the patches of concentrated field strength that the satellites observe in the northern hemisphere.

"This jet of liquid iron is moving at about fifty kilometres per year," explained Dr Chris Finlay from the National Space Institute at the Technical University of Denmark (DTU Space).
“That might not sound like a lot to you on Earth's surface, but you have to remember this a very dense liquid metal and it takes a huge amount of energy to move this thing around and that's probably the fastest motion we have anywhere within the solid Earth,” he told BBC News.

Dr Finlay was speaking here at the American Geophysical Union (AGU) meeting in San Francisco, just ahead of the official publication of the research in the journal Nature Geoscience.
...

Dr Finlay and colleagues want us to envision something similar but made of metal and 3,000km down, under our feet.
They assess the jet to be about 420km wide, and say it wraps half-way around the planet.
Its behaviour will be critical to the generation and maintenance of the global magnetic field, they add.

“It's likely that the jet stream has been in play for hundreds of millions of years," said Dr Phil Livermore from Leeds University, UK, and the lead author on the journal paper.

In the paper, the team puts forward a model to explain the jet.
...

That the team can make such inferences speaks to the impressive capabilities of the Swarm constellation.
Launched in November 2013, the European Space Agency satellites are providing unparalleled insights into the structure and behaviour of Earth's magnetic field.
With their highly sensitive instruments, they are gradually teasing apart the field's various components - from the dominant signal coming from the movement of iron in the outer core to the almost imperceptible contribution made by ocean currents.

It is hoped the Swarm satellites’ data could ultimately tell us why Earth’s magnetic field has been weakening in recent centuries.
Scientists have speculated we could be on the cusp of a polarity reversal, which would see North become South, and South become North.
This occurs every few hundred thousand years.

http://www.bbc.co.uk/news/science-environment-38372342
 
Perhaps the weakening of the Earth's magnetic field may partly explain global warming? More ionised particles reaching the edge of the atmosphere...?
 
If anything I would then expect those particles to lead to cooling via cloud seeding.
 

Earth’s Core Has Stopped and May Be Reversing Direction, Study Says


Earth’s inner core has recently stopped spinning, and may now be reversing the direction of its rotation, according to a surprising new study that probed the deepest reaches of our planet with seismic waves from earthquakes.

The mind-boggling results suggest that Earth’s center pauses and reverses direction on a periodic cycle lasting about 60 to 70 years, a discovery that might solve longstanding mysteries about climate and geological phenomena that occur on a similar timeframe, and that affect life on our planet.

Yi Yang  and Xiaodong Song, a pair of researchers at Peking University’s SinoProbe Lab at School of Earth and Space Sciences, have captured “surprising observations that indicate the inner core has nearly ceased its rotation in the recent decade and may be experiencing a turning-back in a multidecadal oscillation, with another turning point in the early 1970s,” according to a study published on Monday in Nature Geoscience.

https://www.vice.com/en/article/xgy...ped-and-may-be-reversing-direction-study-says

maximus otter
 

Earth’s Core Has Stopped and May Be Reversing Direction, Study Says


Earth’s inner core has recently stopped spinning, and may now be reversing the direction of its rotation, according to a surprising new study that probed the deepest reaches of our planet with seismic waves from earthquakes.

The mind-boggling results suggest that Earth’s center pauses and reverses direction on a periodic cycle lasting about 60 to 70 years, a discovery that might solve longstanding mysteries about climate and geological phenomena that occur on a similar timeframe, and that affect life on our planet.

Yi Yang  and Xiaodong Song, a pair of researchers at Peking University’s SinoProbe Lab at School of Earth and Space Sciences, have captured “surprising observations that indicate the inner core has nearly ceased its rotation in the recent decade and may be experiencing a turning-back in a multidecadal oscillation, with another turning point in the early 1970s,” according to a study published on Monday in Nature Geoscience.

https://www.vice.com/en/article/xgy...ped-and-may-be-reversing-direction-study-says

maximus otter
Buying more 'bags for life' and removal of all gas boilers will solve this.
 
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