Nuclear Reactor At The
Center Of The Earth

By Jonathan Leake
Science Editor
The Times - London

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.
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.
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.
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.
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.
"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.
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.
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.
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.
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.
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.
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."
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."
From John Albrecht
Regarding the "Nuclear Reactor At The Center Of The Earth" article by Jonathan Leake
Science Editor The Times - London on 8-4-2...
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.
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.
There may be some new components in the "new theory" but the substantive portion is old hat.
John Albrecht
Phoenix, AZ


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