- A five-mile-wide ball of uranium and plutonium acting
like a giant nuclear reactor at the centre of Earth is the source of the
energy that sustains life, according to controversial new research.
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- The natural reactor generates Earth,s magnetic shield,
which protects the planet from bombardment by deadly particles from the
sun. It also provides the energy that powers volcanoes and the movement
of continental plates.
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- If true, the theory would overturn current ideas of what
lies at the heart of our planet. They suggest Earth,s core contains a huge
ball of solidified iron and nickel surrounded by a molten mantle.
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- The new theory would also bring Earth,s life to an end
far earlier than previously forecast. Instead of lasting up to four billion
years, the planet will die in just two billion years as the reactor runs
out of fuel, cools and the protective magnetic shield is dissipated.
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- The study, by scientists at the US Department of Energy,s
Oak Ridge Laboratory, looked at the radioactive elements given off during
volcanic eruptions. They also designed a sophisticated computer model of
how a reactor at the Earth,s core might behave.
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- "We found strong evidence that 4,000 miles beneath
our feet the Earth's core contains a fast-neutron breeder reactor made
of uranium and plutonium, a type that can regenerate new fuel for itself.
What's more, such a reactor would have a life similar to that of the Earth,"
said Marvin Herndon, the Oak Ridge researcher who presented the findings
at a recent conference of the American Geophysical Union.
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- Herndon and his collaborator, Daniel Hollenback, say
the theory explains mysteries that have baffled experts. One is the way
Earth's magnetic field is generated. Some theories suggest it derives from
flows of molten iron around the core, others that it comes from some cooling
mechanism.
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- The Oak Ridge research says such theories cannot explain
why Earth's north and south poles appear to "flip over" every
200,000 years. Under their theory, the reactor would undergo cycles of
activity at the end of which the poles would naturally switch positions.
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- The researchers suggest that similar reactors could lie
at the heart of other planets, too, and that this could explain why Jupiter,
among others, radiates nearly twice the energy it receives from the sun.
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- Some of the strongest evidence for the theory comes from
lava spewed up from deep beneath the ocean bed near Hawaii and Iceland.
It contains relatively high levels of helium-3, an isotope formed only
during fission reactions. It had been explained as a leftover from the
formation of Earth but Herndon,s calculations show that the ratios in which
it occurs can be explained only by an underground reactor.
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- The researchers believe the five-mile-wide ball of uranium
has been operating as a nuclear reactor for about 4.5 billion years with
an output of about 4m megawatts.
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- Some scientists are sceptical. Kathy Whaler, professor
of geophysics at Edinburgh University, said she stuck to the traditional
view that Earth,s core was slowly cooling: "I am doubtful of this
new theory. I would be extremely surprised if there were enough radioactive
elements to produce a reaction."
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- Herndon said: "One huge implication is that the
nuclear reactor will run out of fuel. When it does, the magnetic field
that protects us will die - and so will we."
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- Comment
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- From John Albrecht
- 8-5-2
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- Regarding the "Nuclear Reactor At The Center Of
The Earth" article by Jonathan Leake
- Science Editor The Times - London on 8-4-2...
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- In the article, Mr. Leake indicated this was a new theory.
In fact, the theory that the core of the Earth is composed of nuclear
material has been around for quite some time: at least since I was in
high school some 30 years ago.
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- It was used to explain at least one of several possible
sources that produce heat within the Earth. Some other main ones were
gravity, friction, and left-over molten material from the formation of
the planet.
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- There may be some new components in the "new theory"
but the substantive portion is old hat.
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- Regards,
- John Albrecht
- Phoenix, AZ
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