Thu, 27 Mar 2003 09:23 CST
New government laboratory test results are fueling a controversial contention that a giant natural nuclear reactor at the center of the Earth powers the planet's life-protecting magnetic field -- but it might be running out of gas, scientists told United Press International.
The scenario parallels the plot of a science-fiction thriller that opens Friday.
Geophysicist J. Marvin Herndon sees the findings, reported in the prestigious journal Proceedings of the National Academy of Sciences, as irrefutable support for his convention-defying view of Earth containing a gigantic natural nuclear power plant.
His bold theory sets a 5-mile-wide broiling wad of uranium deep within Earth's bowels, churning out heat that ignites sleeping volcanoes and drifting continental plates and creating a shield that protects all life from the deadly ravages of the sun's radiation.
In contrast, the traditional view, favored by most geoscientists for the past 60 years, paints the inner core as a 300-times-larger ball of partially crystallized iron and nickel that gradually cools and expands as it oozes heat into a fluid core.
The computer simulations, conducted at the Oak Ridge National Laboratory in Oak Ridge, Tenn., provide the strongest evidence yet that a core georeactor has been at work for some 4.5 billion years, the widely accepted age of Earth -- and that an end to its lifetime might be approaching, Herndon contends.
"The Earth's nuclear furnace could die in as little as 100 years or as long as 1 billion years -- the uncertainty is great," said Herndon, president of Transdyne Corp. of San Diego.
However, most of his fellow scientists think otherwise.
"There are no indications, based on the study to date, that the georeactor is shutting down," said Daniel Hollenbach, an Oak Ridge nuclear engineer and Herndon's former collaborator, who ran the tests.
"Even if a self-sustained critical reaction could no longer be maintained by the nuclear reactor in the core, it would take thousands, if not millions, of years for us to see an effect," he told UPI. "It is also possible the core has not used even half of the fuel available. The reactor could operate another 4.5 billion years."
However, Hollenbach supports the soundness of the core proposal, which many geoscientists do not.
"I think the theory of a nuclear reactor deep inside the Earth is valid," Hollenbach said. "Certain simulations done by me at ORNL provide corroborating evidence."
The simulations of a nuclear reactor at work over billions of years put forth what Herndon sees as the most compelling argument for his theory.
Using the data, Herndon showed software that tracks fuel usage at nuclear power plants indicates the georeactor could have been blazing away over Earth's lifetime at heat levels that match the planet's actual output of some 4 million megawatts -- enough to run 40 billion 100-watt light bulbs. Much of the energy comes in the form of heat, the potential power behind the mechanisms that create the geomagnetic field, Herndon said.
Moreover, the computer programs suggested that such a reactor would vary in intensity -- from strong to weak to occasionally non-existent -- which could explain the roller-coaster behavior of the magnetic field, Herndon explained. Evidence shows that through the millennia, the field has waxed, waned and, every 200,000 years or so, reversed.
"The most important implication of the findings would be to explain the source of the magnetic field, one of the great unresolved problems of our time," David Deming, associate professor of geology and geophysics at the University of Oklahoma in Norman, said in a telephone interview. "If Marvin is right, that would be one of the great triumphs of geology."
Thus far, however, Herndon's persistent pursuit of proving his proposal has claimed few victories among the scientific community, which over the years has stayed largely silent about his work.
His first challenge to the conventional view of the composition of Earth's core, published in 1979 in the Proceedings of the Royal Society of London, for example, has been cited as a reference by other researchers only three times in the past 24 years, Herndon admitted.
"A curtain of silence fell down -- and it's been down ever since," he said in a telephone interview. He would much rather be contested than ignored, he added.
The reason he is not contested is because most other scientists view his work as "just an interesting speculation," Don Anderson, professor of geophysics at the California Institute of Technology in Pasadena, told UPI.
David Stevenson, George Van Osdol professor of planetary science at Caltech, was even more dismissing. Asked to assess Herndon's arguments, he quoted from an e-mail he recently sent a student who was writing a term paper on the research:
"Scientists respond strongest to things they take seriously but suspect are incorrect," Stevenson wrote. "Herndon's work is simply not taken seriously and really doesn't deserve to be taken seriously."
Herndon and his supporters see the opposition as part pragmatics, part politics.
"Herndon stirred up so many arguments opposed to the paradigms of the day, I can see why he's gotten the reactions he has," said Hatten Yoder, director emeritus of the Geophysical Laboratory of the Carnegie Institution of Washington and member of the National Academy of Sciences, who sponsored the latest PNAS paper.
"I like and respect the way Herndon does his research," he said in a telephone interview.
Jaro Franta, a professional engineer with Atomic Energy of Canada Ltd. in Montreal, said he and probably others entertained the possibility of a georeactor at the center of the Earth, but Herndon got down to business and had his paper published.
"That was something of a risk, since interdisciplinary research often runs into resistance," he told UPI.
Herndon tackles the conventional view of Earth's core head-on. In his scenario, flows of charged particles dancing around a fiery nuclear reactor -- rather than molten iron and nickel whirling around a solid iron-nickel ball, as the dominant theory has it -- propel the Earth's magnetic field like a gigantic electric motor.
"If the theory of a deep Earth reactor proves true and it is the driving mechanism for the geomagnetic field, we owe our existence to it," Hollenbach said. "Solar radiation would have stripped off our atmosphere long ago without the repulsion provided by the field."
If proved true, the theory also will make a major contribution to geoscience, Yoder asserted.
"This is on a scale of (the theory of) plate tectonics, which took 50 years to accept," Yoder told UPI. "I think Herndon's got something just as big, just as important."
Should Herndon's view prevail, it would send a rumble heard throughout the geophysical world, scientists said. Though it could explain certain unsolved mysteries theoretically -- from the vagaries of Earth's shield to the whimsies of the mysterious dark matter that astronomers say is 10 times more common than visible matter -- it would require a radical revision of standard views on how much of the material universe operates.
Hollenbach listed three basic arguments favoring a planetary nuclear reactor:
-- It explains the source of energy that has kept Earth's core molten since birth. "Without an energy source, the Earth would cool and the core would solidify in about 10 million years," Hollenbach said. "The current best geophysics theory is that the core is composed of molten iron/nickel that is slowly crystallizing, and it is the latent heat of crystallization that provides the energy. Unfortunately, geophysicists have been unable to make the thermodynamics fit this model (i.e., it does not produce enough energy and cools too rapidly)."
-- It explains the fluctuations of Earth's magnetic field, which range from high activity to shutdown, occasionally reversing polarity, with the North and South poles exchanging their magnetic charges. "If the magnetic field is tied to the power produced in the Earth's core, it would require an energy source that also fluctuates," Hollenbach said. "A nuclear reactor would naturally fluctuate between a high and low power. As fission products build up, the reactor would shut down, and as the (lighter) fission products migrate out of the reactor region due to density differences, the reactor would start up."
-- The simulations performed at the government lab produced results that match precisely what occurs in nature, specifically in lava rocks from midocean ridges and volcanic hot spots, such as Hawaii and Iceland.
The basalt rock, spewed from a heat source deep within Earth, seems to contain evidence of the nuclear fission processes that gave it birth, Herndon speculated. In splitting elements, a core reactor would produce byproducts, some of which might escape as a witness to its existence, he reasoned. A relatively light element such as helium could traverse the 3,959 miles to the surface easily, to tell the story of what goes on far below, he explained.
As it turns out, over the past 33 years, scientists have measured traces of two types of helium, one with a mass of 3 and one with a mass of 4, in such basalt samples, Herndon noted. The helium-4, known as a byproduct of radioactive decay, was no surprise. However, investigators know of no earthly explanation for the presence of helium-3. Instead, they attributed its source to a primordial leftover from Earth's formation or a remnant of cosmic dust.
No known physical process on Earth can produce the element -- except for nuclear fission, Herndon stressed. The simulations produced precisely the proportion of the two helium types, or isotopes, found in the lava rock, he noted. To him, that is strong evidence for the reactor at Earth's core.
"Nothing was done to make those results come out the way they did," Herndon said. "They could have been anything, but they weren't. They were a precise match."
The results show a progressive increase in the helium-3 to helium-4 ratio over time, with the highest values occurring near the end of a georeactor's lifetime as the uranium fuel becomes depleted. It turns out scientists are finding just such high ratios in lava rocks from deep volcanic hot spots in Hawaii and Iceland, Herndon remarked.
"That's the first indication we're nearing the end," he told UPI.
The evidence is not as convincing as Herndon would like, however.
"Our current understanding leaves plenty of wiggle room: no samples from the core, limited knowledge of the chemistry of uranium at high pressure," Lars Stixrude, associate professor of geological sciences at the University of Michigan in Ann Arbor, told UPI. "So one has to admit that it would be difficult at present to disprove the presence of concentrated uranium in the core, but, by the same token, it would be difficult to prove."
Yoder told UPI he does not worry about the world soon coming to end, "but so long as the helium ratio curves are pointing up and the reactor is diminishing, we must say someday, sometime it will end."
When it does, life will change forever, Herndon predicted. Without the georeactor's support, Earth's magnetic shield will collapse, permitting the solar wind to bombard the planet mercilessly.
A fictional portrayal of what would happen is portrayed in a new feature film, Paramount Pictures' "The Core," which opens Friday.
"The dramatic part is when the magnetic field starts collapsing," said Herndon, who offered the filmmakers some post-production scientific advice. "Birds start flying into buildings, pacemakers in heart patients fail all at once, bridges shake with electrical currents. It is a very graphic depiction of what we really are facing."
The science-fiction thriller's release, coming so close to the publication of Herndon's results, is coincidental, said the movie's science-technology liaison Warren Betts.
"Initially, the movie was to be released last November but had to be delayed because the special effects were not ready," Betts told UPI. "So, we had to add a few months to our production schedule. It just so happened that the Proceedings of the National Academy of Sciences (published) Herndon's work (at the same time)."
Herndon hopes the film will inspire classroom discussion of what lies at the center of the Earth and how it affects what goes on at its surface.
"It's important to get that conversation going at any level," he said.
"The geomagnetic field could possibly owe its existence to a nuclear reactor deep inside the core of the Earth," Hollenbach remarked. "Life on Earth is only possible because of the geomagnetic field. Without it, we would be as lifeless as the moon or Mars."