Sunday, April 1, 2007
THE LIVING EARTH IS NUCLEAR
Is Indian Point simply a local use of the most natural of all nature's gifts?
Is the core of the earth simply another Indian point, 5000 miles below our feet?
If we worship the earth as "Gaia", is the living heart of Gaia a natural uranium reactor?
http://www.etherzone.com/2002/jud071202.shtml
GOD IS A NUCLEAR REACTOR ENVIRONMENTALIST EARTH WORSHIPERS
By: William Jud
Brad Lemley writes, on pages 35 - 42 in the August 2002 issue of Discover Magazine, about geophysicists' discovery that the exact center of the earth is a ball of molten uranium five miles in diameter which is a natural nuclear fission reactor.
A natural nuclear reactor at the earth's core provides energy that drives volcanic activity and continental drift, and generates earth's magnetic field which deflects charged particles from the sun which otherwise would long ago have stripped off earth's atmosphere and killed all life on earth. Natural fluctuations in reactor output due to build-up and dissipation of reactor waste explain observed variations in polarity and intensity of earth's magnetic field, Herndon theorizes.
Evidence so far is supportive, the writer observes. Earth produces about four terawatts of energy, which computer models calculate is what a natural reactor of white-hot uranium five miles in diameter at the earth's exact core center should produce. Other planets such as Jupiter, Saturn and Neptune are known to radiate about twice as much energy into space as they receive from the sun, so perhaps a planetary uranium core reactor is the norm rather than the exception. Heat from earth's core reactor would power volcanic eruptions, and studies of volcanoes in Hawaii find the Helium 3 isotope mixed with the common Helium 4 isotope in gas and volcanic basalt rock coming from Hawaiian volcanic eruptions. Helium 3 is a fission byproduct produced in uranium-powered nuclear reactors.
Minerals exploration geologists know that uranium deposits are found in areas of recent volcanic activity such as New Mexico, often associated with volcanic ash in sedimentary rocks. But volcanic ash, although in many places deficient in uranium due to leaching which could be a mechanism of transporting uranium out of the volcanic ash and into uranium mineral deposits, probably is insufficient to be the entire source of uranium for large uranium deposits. So another factor must have operated, such as uranium introduced into sedimentary host rocks by steam and hot water from volcanic eruptions and associated hot springs. It has not been proven that volcanic activity creates uranium deposits, but spatial correlation has long been observed. Herndon's theory suggests that uranium deposits in sedimentary rock may originate partly as uranium leakage from earth's core reactor, brought to the surface in erupting magma.
Herndon's discovery ought to interest environmentalist Earth Worshipers who proclaim that Gaia, Mother Earth, is God, and that Gaia is the source of life and well-being for humans and all other life on Earth.
Environmentalists oppose nuclear reactors used to generate power for ships and electricity for domestic use. Environmentalists complain that nuclear power reactors are evil and dangerous and must not be allowed anywhere. If Herndon is right, and Gaia, Mother Earth, lives on energy produced by a giant nuclear reactor at the very heart and core of her being, then Gaia must have a heart and core of Uranium. Gaia and all Earth's creatures may owe their existence to a uranium-fired nuclear reactor at earth's core.
If geophysicist Herndon's findings are correct, Gaia's environmentalist true believers worship a nuclear reactor.
http://www.rense.com/general25/vore.htm
Giant Nuclear Reactor Runs
Earth's Magnetic Field
By Phil Berardelli
UPI Deputy Science and Technology Editor
6-11-2
Thousands of miles beneath our feet, a giant nuclear reactor seems to be at work deep within Earth's core, and preliminary research suggests it may be the mysterious power source behind the planet's magnetic field and thermal energy, upon which all life on the planet depends for its survival, scientists told United Press International.
New data analyzed by J. Marvin Herndon, geoscientist and president of Transdyne Corporation, of San Diego, Calif., and Daniel F. Hollenback, a nuclear engineer and criticality expert at Oak Ridge National Laboratory, in Oak Ridge, Tenn., show the reactor -- a ball of uranium about five miles in diameter and located at the center of the core -- may have been operating nearly since the formation of the planet.
Herndon told UPI he has been searching for evidence of the deep-Earth reactor for more than a decade. In 1992, he published a series of papers on planet-sized nuclear reactors based on the discovery, 20 years earlier, of the remnants of a large, natural reactor located at the Oklo uranium mine in the Republic of Gabon in western Africa.
French scientists had discovered the Oklo reactor and determined it had operated for tens of thousands of years some two billion years ago, Herndon said, "but at the time of its discovery there were too many pieces missing to know what that really meant."
Nuclear reactors operating inside planetary cores might explain some mysteries that have puzzled scientists for years, Herndon said. For example, since the 1960s, astronomers have known Jupiter radiates nearly twice the energy it receives from the Sun. But up to now, they have not been able to explain the phenomenon in a way that makes sense, he said.
Earth's magnetic field is an even bigger mystery. Some mechanism obviously generates the field, and many scientists think the field is formed from fluid iron in Earth's main outer core acting like a giant electric dynamo, or motor. The geomagnetic field, as it is called, shuts down periodically and sometimes reverses its polarity -- with the North and South poles exchanging their magnetic charges.
The energy sources previously thought to power the dynamo are unable to decrease and then increase again, Herndon explained, so scientists have had to resort to assuming the dynamo mechanism is inherently unstable. But a nuclear reactor can decrease power output -- and even shut itself down -- and come back to life again, increasing to its full operating power, he said.
Current knowledge of the structure of Earth's interior is derived mainly from seismic data and chemical analyses of common meteorites, Herndon continued. Based on that data, scientists estimate about 30 percent of Earth's mass comprises an outer core, he said, which is thought to consist of iron and maybe one or more lighter elements such as sulfur.
The solid inner core is much smaller -- less than 2 percent of Earth's mass.
Still, current popular geophysical models cannot explain, from an energy standpoint, a planet-sized magnetic field that operates like Earth's -- with its varying power levels and periodic shutdowns, Herndon said.
Herndon said he received a major insight when he studied a different type of meteorite. Enstatite chondrite meteorites, as they are called, have chemical compositions similar to Earth's interior. Unlike more common meteorites, enstatite chondrite meteorites contain most of their uranium in the part of the meteorite that corresponds to Earth's core.
It was one of the clues Herndon needed, he said. Uranium is the heaviest natural element. It makes sense that, over time, solid uranium particles would rain out from Earth's fluid core at high temperatures. Because of their high density, they could collect at the very center of the Earth. After enough uranium collected together, a nuclear reaction would begin, and that appears to be what happened very soon after the formation of the planet.
In 1997, Herndon teamed up with Hollenbach at Oak Ridge. The laboratory has unique computer programs that can analyze the performance of different types of nuclear reactors.
"Dan showed me those numerical simulation programs could be applied to a nuclear reactor at the center of the Earth," Herndon said. "We used data about the uranium content from the meteorite discoveries to generate simulations at varying power levels."
A highly persuasive clue arrived in the form of physical evidence of a nuclear reactor at Earth's core. Recently analyzed samples of lava rock from deep-source volcanic "hot spots" in Hawaii and Iceland contained tiny amounts of the isotopes helium-3 and helium-4.
Although scientists have known about the helium-3 for some time, they have thought it was left over from Earth's formation some four-and-a-half billion years ago. But no known physical process could produce helium-3 except for nuclear fission, Herndon said, and the proportion of the two helium isotopes matches the prediction of the Oak Ridge simulation. This is strong evidence that the geo-reactor is at work, he said.
Based on the simulations, and the helium evidence, Herndon and Hollenbach theorize a five-mile-wide ball of uranium has been operating as a nuclear reactor for about 4.5 billion years. Its output is an awesome 4 million megawatts. Much of the energy it produces is heat, and that might be what powers the mechanism that produces the geomagnetic field, Herndon said.
Perhaps more interesting, the Oak Ridge programs suggest the reactor is a breeder -- that is, it actually produces more nuclear fuel than it consumes, which is why it has been able to operate over a time frame that spans nearly the entire existence of the planet. In addition, the reactor's power level varies in intensity over time and it shuts down periodically.
A nuclear reactor continuously produces lighter elements, such as strontium or barium, as the uranium fuel fissions -- or splits apart. Those fission fragments would begin to absorb neutrons -- the subatomic particles naturally emitted by the fissioning uranium and responsible for the chain reaction -- thereby preventing them from splitting other atoms.
"One might imagine instances in which the rate of production of fission products exceeds their rate of removal by gravitationally driven diffusion," Herndon wrote in a recent paper on the subject. If so, he explained, "the power output of the geo-reactor would decrease and the reactor might eventually shut down, thereby diminishing and ultimately shutting down the Earth's magnetic field."
Over time, as the lighter elements moved away from the uranium core, the reactor would restart.
The research is "certainly going to be a major contribution to geophysics," Hatten S. Yoder, Jr., director emeritus of the Geophysical Laboratory of the Carnegie Institution of Washington, D.C., told UPI. "They have developed an explanation for (Earth's) magnetic field and the fact that you can turn it on and off."
One of the most remarkable aspects of the planetary core reactor, Yoder said, is "it only takes a (five-mile) ball of uranium. That's only 65 percent of all the uranium on Earth."
The reactor's existence, if proven, solves the problem of delayed geothermal cooling and explains the observed heat flow, Yoder said. Without a continuing power source, he said, the heat dissipation would have ended long ago. But "if you have a ball of uranium at the center, it would continue to put out heat."
Herndon said he next plans to search lava samples for traces of radioactive elements that might have been produced by the geo-reactor and be light enough to have escaped the core and reach Earth's surface. Lithium, beryllium, boron and neon are possibilities, he said.
"It's not an easy task because both rock data and nuclear data are needed, but it certainly is important," Herndon said.
Yoder agreed. "High-temperature and high-pressure experiments are needed to test the composition and melting characteristics of the core," he said.
Copyright 2002 by United Press International.
http://www.technologyreview.com/offthewire/3001_662002_6.asp
Note - South African author-researcher Jan Lamprecht proposed the same concept several years ago during an interview with Jeff. You can read more about his revolutionary theories at www.HollowPlanets.com.
Note from Jan regarding the above story:
Jeff -
Dr Herndon and I communicated a lot, and he's a great guy. That man can turn physics on its head (ditto for the other nuclear scientists who agree with him). All this nonsense about "convection currents in the core" - phooey.... Planets run on nuclear reactors... which is the first of several revelations to come...
Regards, Jan
http://www.ebtx.com/theory/core.htm
Rotational Velocity
of the earth's core
Recently, news from sci-sites reported that the core of the earth is rotating faster than the crust by about a degree per year. In 1400 years or so it will have "lapped" the surface. The scientific cause of this phenomenon has possibly to do with the earth's magnetic field waxing and waning (or so they say). I think it is more likely due to simple thermal expansion and contraction and corresponding angular momentum conservation.
The Nuclear Furnace
There is some excitement that the core's center is occupied by a 5 kilometer diameter uranium furnace which augments the heat generated by the contraction of the earth and all the comets and asteroids that have delivered energy to it in the past. Because the rocky crust is a reasonable insulator we are still alive, i.e. no heat = no swirling molten iron = no magnetic field = no protection from solar radiation = hasta la vista ocean and atmosphere and ola! Mars clone.
My guess is that this is so. Heat is then continuously transmitted through the radius of the earth to vent into space via vulcanism. The entire train of vulcanism must run like this then.
• Core is heated by uranium.
• Heat is transferred through the core to the mantle mainly by rising convective cells (which also cause the magnetic fields)
• The heat is taken up by secondary convective cells at the core-mantle boundary
• These cells rise to the surface exactly like a lava lamp
• They break through the surface as volcanos where the heat gets vented
This doesn't seem too radical to me. Some think that the origin of magma is the upper mantle, meaning that this opinion favors "contact" heat transfer through the "plastic" mantle, i.e. convective cells are here impossible because they require a more fluid flow. Hmmmmmm ... I politely disagree but acknowledge fallibility because I can't see down there. But those who think they can, say the core-mantle interface is very "lumpy". I interpret this in the light of the lava lamp model.
Lava Lamp Bubbles as the cause of Plate Techtonics
All the motions of the crust's plates have been mapped and they show a more or less random pattern of movement. Some plates are colliding, others are separating and still others are scraping by one another ... and all combinations of the above. To me, this means that the plates are being pushed obliquely by "something". The heat transfer can't be going smoothly like light radiating from a lamp in all directions. If the lava lamp bubbles came straight up to the crust, they would not be able to push the plates sideways. Hence, the bubbles have non-perpendicular momentum relative to the crust.
There are two methods of acquiring such oblique vectors. These are by Coriolis forces operating on the bubbles as they rise through the mantle and from the moon tugging on the crust ... pulling it westbound. If this is true, there should be significantly less volcanos at the poles than near the equator (though it certainly is not impossible to have a polar volcano ... it's just unlikely that a bubble would rise straight up from the pole ... rather, most bubbles in this area would drift away from the poles as they rose and come out at lower latitudes). A notable problem with this conjecture is that the older Hawaiian Islands are to the west of Hawaii (the big island) ... meaning that Mauna Loa sits on the current "hot spot" which is drifting east under the crust. Well, this is a problem because I would expect the opposite to be the case if the east-west differential between the crust and mantle were caused by an oblique hit from underneath, i.e. the hot spot should be drifting in the other direction.
Angular Momentum Conservation
Observe that nature tends not to do things smoothly but rather chaotically which flattens out to smooth over long time periods. For instance, a flag in a constant breeze develops ripples which are more or less identical from one time period to the other. The air can't pass over the flag without turbulence which turns into a fairly orderly pattern of waves in the flag fabric. The same is undoubtedly true of convection in the core and mantle. We get chaotic bubbles which are orderly over long time periods.
As heat is taken from the core, the core alternately heats and cools in the aforementioned chaotic manner. The core is in a cooling phase right now. Thus, the core has shrunk somewhat because it has cooled. Hence, it speeds up to conserve angular momentum. On the other hand, the mantle is in its heating phase and has expanded. Hence, it slows down a little. The situation should change over time and the core-mantle interface should flip relative directions.
The Effect of the Moon
The moon's gravitational tug on all of this muddies the theoretical waters. How much does it pull on the crust? Is it enough to override the oblique push in the opposite direction in the case of Hawaii? Or does it pull everything uniformly so that we can "x" it out of the problem? I don't know.
washingtonpost.com
Earth's Core Is a Nuclear Fission Reactor.
By Guy Gugliotta Washington Post Staff Writer Monday, March 24, 2003; Page A06
Jules Verne thought you could get to the center of the Earth through the chimney of an extinct Icelandic volcano. At the bottom, he envisioned a vast inland sea -- really inland, as in 4,000 miles down -- and a bunch of dinosaurs.
This, it turned out, was science fiction.
These days we know more, and this week Paramount Pictures will release "The Core," in which a team of intrepid "terranauts" try to reverse the collapse of the Earth's magnetic field by traveling to the metal center of the planet and setting off a nuclear bomb.
This is somewhat closer to reality, since it reflects the prevailing view that the Earth's core is made of partially crystallized iron and nickel, and makes use of the idea that heat from the cooling core contributes to the magnetic field that repels solar radiation and keeps it from frying the Earth to a crisp.
Still, no one knows exactly what's down there and, despite "The Core," there are no terranauts getting ready to find out.
The question is still open, and maverick geophysicists have made a discovery in many ways as radical as Verne's was 150 years ago: The center of the Earth, they have found, is a nuclear fission reactor.
And in the Proceedings of the National Academies of Science earlier this month, it was argued that the mix of helium isotopes rising in lavas to the Earth's surface suggested that the "demise of the georeactor" is approaching. The reaction could cease anytime from 100 years to 1 billion years from now, collapsing the Earth's magnetic field with monumental consequences.
Nevertheless, "I'm not a bit worried," one researcher said in an interview. "I don't know how long it will take when it starts -- maybe hundreds of years. In this paper, we say that we have perhaps the first warning."
The American Academy of Science and Paramount have forged a publicity partnership of sorts. Although the Academy says they have not received any money from the film company, they are unabashedly lauding "The Core" in hopes of raising the "curtain of silence" that has stymied debate on this subject since its discovery 12 years ago.
"I like the way he does his science, but I can't say the same about the people who review his work," said Hatten S. Yoder Jr., former director of the geophysical lab at the Carnegie Institution of Washington and one of the Academy's most influential boosters. "The geophysical community has been doing this for years. We've had a terrible time, and I hope this latest paper will generate some civilized discussion."
It does not appear to have done so. "It's a very controversial topic," said Don L. Anderson, a geophysicist at the California Institute of Technology. "I'm a little more open-minded than many of my colleagues," he added, noting that georeactors explain many anomalies in the Earth's crust and mantle. But it is "ridiculous" to suggest that the Earth's geomagnetic field is threatened, he said.
Most scientists agree that the Earth was formed about 41/2 billion years ago from an amalgam of fiery material that contained all of the elements found in nature. Disagreement begins over what happened next.
The view held by most Earth scientists is that iron and nickel migrated downward, taking with them all the trace elements that readily combine with these metals. The rest of the trace elements, including uranium, combined with oxygen to form oxides that remained in the Earth's mantle and crust.
These scientists use common meteorites as their model, but the Academy used a rare meteorite with a small amount of oxygen as his example, arguing that the uranium would remain metallic and, as the heaviest element in nature, would migrate to the Earth's core, forming a sphere about five miles in diameter -- a natural nuclear fission reactor.
"It's a self-sustaining critical reaction," said nuclear engineer Daniel F. Hollenbach of Oak Ridge National Laboratory, a longtime collaborator until the two parted ways last year. "Depending on how much it fissions, that's the power."
Hollenbach explained that the core would be composed primarily of two uranium isotopes. Atoms of the isotope U235 would split, giving up neutrons, which would be absorbed by the isotope U238, transforming it into an isotope of plutonium -- Pu239. The numbers signify the number of protons and neutrons in the atomic nucleus, known as the atomic weight.
This reaction, the same produced in some nuclear power plants, eventually creates radioactive waste isotopes much lighter than uranium. These migrate upward and outward from the core, "like fizz from a soft drink," Hollenbach said. The heat from the reaction is what drives the Earth's magnetic field.
Hollenbach said it is important to regard the core not as one large, controlled nuclear reaction, but as billions of smaller reactions that "shut down and resume" as waste products are created and expelled. Hollenbach and Herndon theorize that the aggregate fluctuations in the reaction's intensity are what cause the Earth's magnetic field to weaken every 200,000 years and change direction when it starts up again.
Further evidence of the georeactor comes from Hawaii and Iceland, Hollenbach said, where young lava basalts have been recovered that contain the helium isotopes He3 and He4. While He4 is a byproduct of the decay of natural uranium, He3 can only be produced deep within the Earth in a nuclear reaction.
The Academy's latest paper went even further, suggesting that the ratios of He3 to He4 indicated that the georeactor is reaching the end of its life -- albeit in perhaps a billion years. Hollenbach said he agrees with that conclusion.
Anderson noted that French scientists showed in 1972 that a georeactor did exist for millions of years in a uranium deposit in Gabon. Most geophysicists believe that the He3 found in lava is "primordial" -- already there when the Earth congealed.
Also, Anderson noted, scientists have managed to flip the Earth's magnetic field in lab simulations that envision a cooling core. Finally, he said, many experiments use mathematical models based on data gathered from controlled nuclear reactions. "But there's no reason to put the uranium in the core," he said. "It does interesting things even if it's in the crust or upper mantle."
http://www.uic.com.au/nip78.htm
The primary source of energy driving the convection in the mantle is the radioactive decay of uranium, thorium and potassium. In the present Earth, most of the energy generated is from the decay of U-238 (c 10-4 watt/kg). At the time of the Earth's formation, however, decay of both U-235 and K-40 would have been subequal in importance and both would have exceeded the heat production of U-238.
A simple way of viewing the process of plate tectonics - the formation and disposal of oceanic lithosphere - is that this is the mechanism by which the mantle sheds heat. Conversely, 'mantle plumes/hot spots' are the way the core sheds heat. In terms of total heat loss from the Earth at present, plate activity constitutes about 74%, hot spots account for approximately 9% and radiogenic heat lost directly from the continental crust is some 17%. The Earth is well insulated thermally and the heat loss from the surface now can reflect heat generation a considerable time in the past.
Measurements of heat have led to estimates that the Earth is generating between 30 and 44 terawatts of heat, much of it from radioactive decay. Measurements of antineutrinos have provisionally suggested that about 24 TW arises from radioactive decay. Professor Bob White provides the more recent figure of 17 TW from radioactive decay in the mantle. This compares with 42-44 TW heat loss at the Earth's surface from the deep Earth. The balance comes from changes in the core. (There is very much greater heat loss arising from incident solar radiation, which is quite distinct.)
Natural nuclear reactors in the Earth's crust
At Oklo in Gabon, West Africa, about 2 billion years ago, at least 17 natural nuclear reactors commenced operation in a rich deposit of uranium ore. Each operated at about 20 kW thermal. At that time the concentration of U-235 in all natural uranium was 3.7 percent instead of 0.7 percent as at present*.
* U-235 decays much faster than U-238, whose half-life is about the same as the age of this planet.
These natural chain reactions, started spontaneously by the presence of water acting as a moderator, continued for about two million years before finally dying away. During this long reaction period about 5.4 tonnes of fission products as well as 1.5 tonnes of plutonium together with other transuranic elements were generated in the orebody. The initial radioactive products have long since decayed into stable elements but study of the amount and location of these has shown that there was little movement of radioactive wastes during and after the nuclear reactions. Plutonium and the other transuranics remained immobile.
Georeactor effect
A quite different view of the role of uranium in the Earth is the discovery that much of the uranium in the primordial planet sunk to the core and has formed a core there, some 8 km across, which has been fissioning ever since. The depletion of U-235 over geological time has not terminated the reaction because this core is a fast reactor (not requiring any moderator) which breeds plutonium-239 from the U-238.
tags: indian point entergy nuclear green natural
PLANET EARTH, A NATURAL NUCLEAR REACTOR
Here's a few links, attesting to the recent activity in this field.
Enjoy!
http://www.physlink.com/News/121103PotassiumCore.cfm
Radioactive material may be primary heat source in Earth's core
Radioactive potassium, common enough on Earth to make potassium-rich bananas one of the "hottest" foods around, appears also to be a substantial source of heat in the Earth's core, according to recent experiments by University of California, Berkeley, geophysicists.
Radioactive potassium, uranium and thorium are thought to be the three main sources of heat in the Earth's interior, aside from that generated by the formation of the planet. Together, the heat keeps the mantle actively churning and the core generating a protective magnetic field.
But geophysicists have found much less potassium in the Earth's crust and mantle than would be expected based on the composition of rocky meteors that supposedly formed the Earth. If, as some have proposed, the missing potassium resides in the Earth's iron core, how did an element as light as potassium get there, especially since iron and potassium don't mix?
Kanani Lee, who recently earned her Ph.D. from UC Berkeley, and UC Berkeley professor of earth and planetary science Raymond Jeanloz have discovered a possible answer. They've shown that at the high pressures and temperatures in the Earth's interior, potassium can form an alloy with iron never before observed. During the planet's formation, this potassium-iron alloy could have sunk to the core, depleting potassium in the overlying mantle and crust and providing a radioactive potassium heat source in addition to that supplied by uranium and thorium in the core.
Lee created the new alloy by squeezing iron and potassium between the tips of two diamonds to temperatures and pressures characteristic of 600-700 kilometers below the surface - 2,500 degrees Celsius and nearly 4 million pounds per square inch, or a quarter of a million times atmospheric pressure.
"Our new findings indicate that the core may contain as much as 1,200 parts per million potassium -just over one tenth of one percent," Lee said. "This amount may seem small, and is comparable to the concentration of radioactive potassium naturally present in bananas. Combined over the entire mass of the Earth's core, however, it can be enough to provide one-fifth of the heat given off by the Earth."
Lee and Jeanloz will report their findings on Dec. 10, at the American Geophysical Union meeting in San Francisco, and in an article accepted for publication in Geophysical Research Letters.
"With one experiment, Lee and Jeanloz demonstrated that potassium may be an important heat source for the geodynamo, provided a way out of some troublesome aspects of the core's thermal evolution, and further demonstrated that modern computational mineral physics not only complements experimental work, but that it can provide guidance to fruitful experimental explorations," said Mark Bukowinski, professor of earth and planetary science at UC Berkeley, who predicted the unusual alloy in the mid-1970s.
Geophysicist Bruce Buffett of the University of Chicago cautions that more experiments need to be done to show that iron can actually pull potassium away from the silicate rocks that dominate in the Earth's mantle.
"They proved it would be possible to dissolve potassium into liquid iron," Buffet said. "Modelers need heat, so this is one source, because the radiogenic isotope of potassium can produce heat and that can help power convection in the core and drive the magnetic field. They proved it could go in. What's important is how much is pulled out of the silicate. There's still work to be done "
If a significant amount of potassium does reside in the Earth's core, this would clear up a lingering question - why the ratio of potassium to uranium in stony meteorites (chondrites), which presumably coalesced to form the Earth, is eight times greater than the observed ratio in the Earth's crust. Though some geologists have asserted that the missing potassium resides in the core, there was no mechanism by which it could have reached the core. Other elements like oxygen and carbon form compounds or alloys with iron and presumably were dragged down by iron as it sank to the core. But at normal temperature and pressure, potassium does not associate with iron.
Others have argued that the missing potassium boiled away during the early, molten stage of Earth's evolution.
The demonstration by Lee and Jeanloz that potassium can dissolve in iron to form an alloy provides an explanation for the missing potassium.
"Early in Earth's history, the interior temperature and pressure would not have been high enough to make this alloy," Lee said. "But as more and more meteorites piled on, the pressure and temperature would have increased to the point where this alloy could form."
The existence of this high-pressure alloy was predicted by Bukowinski in the mid-1970s. Using quantum mechanical arguments, he suggested that high pressure would squeeze potassium's lone outer electron into a lower shell, making the atom resemble iron and thus more likely to alloy with iron.
More recent quantum mechanical calculations using improved techniques, conducted with Gerd Steinle-Neumann at the Universität Bayreuth's Bayerisches Geoinstitüt, confirmed the new experimental measurements.
"This really replicates and verifies the earlier calculations 26 years ago and provides a physical explanation for our experimental results," Jeanloz said.
The Earth is thought to have formed from the collision of many rocky asteroids, perhaps hundreds of kilometers in diameter, in the early solar system. As the proto-Earth gradually bulked up, continuing asteroid collisions and gravitational collapse kept the planet molten. Heavier elements – in particular iron - would have sunk to the core in 10 to 100 million years' time, carrying with it other elements that bind to iron.
Gradually, however, the Earth would have cooled off and become a dead rocky globe with a cold iron ball at the core if not for the continued release of heat by the decay of radioactive elements like potassium-40, uranium-238 and thorium-232, which have half-lives of 1.25 billion, 4 billion and 14 billion years, respectively. About one in every thousand potassium atoms is radioactive.
The heat generated in the core turns the iron into a convecting dynamo that maintains a magnetic field strong enough to shield the planet from the solar wind. This heat leaks out into the mantle, causing convection in the rock that moves crustal plates and fuels volcanoes.
Balancing the heat generated in the core with the known concentrations of radiogenic isotopes has been difficult, however, and the missing potassium has been a big part of the problem. One researcher proposed earlier this year that sulfur could help potassium associate with iron and provide a means by which potassium could reach the core.
The experiment by Lee and Jeanloz shows that sulfur is not necessary. Lee combined pure iron and pure potassium in a diamond anvil cell and squeezed the small sample to 26 gigapascals of pressure while heating the sample with a laser above 2,500 Kelvin (4,000 degrees Fahrenheit), which is above the melting points of both potassium and iron. She conducted this experiment six times in the high-intensity X-ray beams of two different accelerators - Lawrence Berkeley National Laboratory's Advanced Light Source and the Stanford Synchrotron Radiation Laboratory - to obtain X-ray diffraction images of the samples' internal structure. The images confirmed that potassium and iron had mixed evenly to form an alloy, much as iron and carbon mix to form steel alloy.
In the theoretical magma ocean of a proto-Earth, the pressure at a depth of 400-1,000 kilometers (270-670 miles) would be between 15 and 35 gigapascals and the temperature would be 2,200-3,000 Kelvin, Jeanloz said.
"At these temperatures and pressures, the underlying physics changes and the electron density shifts, making potassium look more like iron," Jeanloz said. "At high pressure, the periodic table looks totally different."
"The work by Lee and Jeanloz provides the first proof that potassium is indeed miscible in iron at high pressures and, perhaps as significantly, it further vindicates the computational physics that underlies the original prediction," Bukowinski said. "If it can be further demonstrated that potassium would enter iron in significant amounts in the presence of silicate minerals, conditions representative of likely core formation processes, then potassium could provide the extra heat needed to explain why the Earth's inner core hasn't frozen to as large a size as the thermal history of the core suggests it should."
Jeanloz is excited by the fact that theoretical calculations are now not only explaining experimental findings at high pressure, but also predicting structures.
"We need theorists to identify interesting problems, not only check our results after the experiment," he said. "That's happening now. In the past half a dozen years, theorists have been making predictions that experimentalists are willing to spend a few years to demonstrate."
The work was funded by the National Science Foundation and the Department of Energy.
http://athene.as.arizona.edu/~lclose/teaching/images/lect8.html
Lecture 8
History of the Earth
Chapter 3
The dynamic Earth (Introduction to Geophysics)
Most geophysical processes stem from the transfer of heat from the Earth's core to its surface.
Why is the Earth's core hot?
1. The radio active decay of Uranium (U), Thorium (Th) and Potassium (K). Each radio active decay (the loss of some neutrons and protons) releases very little energy. However, all the countless events acting together release a large sustained amount of energy overtime. In the core of the Earth this energy is trapped and so the Earth's core is heated up.
2. As the solid inner grows latent heat is released as the molten outer core freezes to solid rock. Eventually the whole Earth will be solid and there will be no magnetic field.
3. Residual formation heat. Some of the kinetic energy (1/2mv2) of the impacting planetesimals would have been converted to heat. This residual formation heat helped melt the core initially.
4. Another early heat source was the heat produced as the heavy elements (like Iron (Fe) and Nickel (Ni)) "falling" into the core. This process also generated heat from friction.
The exchange of heat from the hot core to the cool surface is called convection (heat rises, cold sinks). In this manner the whole Earth has a series of big convective cells in its mantel. The result is a complex series of movements of the crust of the Earth as it "rides" on top of the convective cells below.
Plate Tectonics
In the 1950s and 60s geophysicists started to develop the concept of Plate Tectonics. Plate tectonics is the theory that describes the motion of the continental plates "riding" the tops of these massive convective cells in the Earth (like a conveyor belt).
Here is a movie showing how the plates have moved the continents
Today these plates move by about 10 cm/yr
• when these plates stick, and then suddenly slip, an Earthquake occurs
• when the heavier ocean crust sinks below the lighter (granite) continental crust (at subjection zones) there will be Earthquakes and Volcanos -the ring of fire around the Pacific is built this way. The Continental crust will also be crumpled, and as a result it is typical to see mountain ranges along the edges of these faults (for example the rocky mountains and the Andes).
• Seamount Island Chains -like the Hawaiian Islands- are made when one hot spot in the Earths mantle leads to continuous eruptions in the same spot. But as the crust moves along the ocean floor a chain of new islands appear.Sometimes (but not often) two continental plates collide. In this case neither plate is heavier and so they both "crumple". This is occurring today as the Indian plate collides with the Asian plate. The result of this collision is the Himalayas which are the highest mountains on Earth.Why is a hot core important for life on Earth?
1. the surface temperature is higher
2. active volcanism can out gas the atmosphere and oceans
3. volcanism is required to form land masses above the ocean
4. hot spots in the sea floor can be "safe" habitats for life
5. hot springs and even hot water deep in the Earth can harbor life
6. volcanoes play a role in the Earth's carbon cycle
Basin and Range
Tucson is located in a unique part of the world. The area where we live is called "Basin & Range" geography. This denotes that in Eastern California, Arizona, and New Mexico the terrain is dominated by short (often parallel) mountain ranges with large dry basins between them. This is a highly unusual land form caused by a unique event in the Earth's history.
• About 20 million years ago the continental plate of the Southwest became "attached" somehow to the pacific coast plate which was moving northwest at the time.
• Added to this was intense heat from magma close to the surface.
• The end result was the unique "Basin & Range disturbance" where the coast of California was pulled away from Arizona by some 38% of its original size.
• The hard cold rock on the top splintered into dozens of parallel ranges, while huge basins over 1 km deep were opened up between the rangeThe whole stretching event took a few million years. Then due to erosion the valleys filled in and the ranges wore down --further filling the valleys.
The reason Tucson exists today is because of the "fossil ground water" trapped in the huge 1 km deep valley basin exists below the city.
Radioactivity in Earth's core up for a look
vast uranium field serves as natural reactor
Keay Davidson, Chronicle Science Writer
Monday, November 29, 2004
Researchers are preparing to prove the discoveries of San Diego geologist, J. Marvin Herndon, who has found a huge, natural nuclear reactor or "georeactor" -- a vast deposit of uranium several miles wide -- at Earth's core, thousands of miles beneath our feet. Herndon and many others believe it explains otherwise puzzling phenomena of planetary science, such as fluctuations in the intensity of Earth's magnetic field. "Herndon's idea about (a reactor) located at the center of the Earth, has opened a new era in planetary physics," said four Russian scientists at Moscow's Institute for Nuclear Research and Kurchatov Institute in a Jan. 28 paper published online.
It might sound bizarre, the very idea of a "natural" nuclear reactor -- a geological version of commercial nuclear power plants such as Pacific Gas and Electric Co.'s Diablo Canyon plant near San Luis Obispo. The reactor at the Earth's core is just a much bigger and deeper version of an extinct natural nuclear reactor that scientists discovered in a uranium mine in Gabon, Africa, in 1972.
The Gabon reactor consists of geological deposits of uranium that, being radioactive, naturally emit subatomic particles called neutrons. These neutrons split the nuclei in adjacent uranium atoms, causing them to emit more neutrons and, thus, to split even more uranium atoms -- in effect, it's a slow-speed chain reaction. Research in the 1970s revealed that the Gabon reactor operated intermittently for a few million years about 2 billion years ago.
Scientists have long known the planet's core is divided into a solid and liquid part composed largely of iron, the liquid circulation of which powers Earth's magnetic field. They have not thought of the core as a repository for uranium, because uranium was not understood until 1945. Although the inevitability of uranium in the core was proposed in 1939 by scientist Walter Elsasser, on the basis that it is the heaviest naturally occurring element, so it would migrate to the core via gravity.
Herndon has demonstrated how a uranium georeactor in Earth's core explains reality better than older scientific ideas, by providing more convincing ways to:
-- Explain the ratios of helium isotopes emitted from volcanoes in Iceland and Hawaii. Those ratios are consistent with the ratios of helium isotopes emitted by a nuclear reactor.
-- Explain why planets such as Jupiter emit far more heat than they absorb from the sun. Herndon thinks they, too, have natural nuclear reactors at their cores. (Because heat is continually generated by the decay of radioactive elements in Earth's crust and mantle -- the regions above the core -- scientists are uncertain whether Earth emits more heat than it receives from the sun.)
-- Explain variations in the intensity of Earth's magnetic field, which fluctuates over time. Herndon has shown that in the core, the georeactor drives the motions of the liquid iron that creates the magnetic field. But the georeactor varies in activity levels over time. Those activity variations, he believes, might explain intensity variations in Earth's magnetic field.
Now, Rob de Meijer and associates at the Nuclear Physics Institute in Groningen, the Netherlands, are planning to demonstrate Herndon's proposals. They're drawing blueprints for a large device that could detect ghostly particles called antineutrinos that have escaped from Earth's core. When put into operation, it will capture antineutrinos that would fly through the roughly 4,000 miles of solid rock and emerge at the Earth's surface.
The European scientists have proposed drilling a shaft more than 1,000 feet deep into the island of Curacao in the Caribbean. They hope to lower into the shaft devices called photomultipliers, which could detect particles from the hypothetical deep-Earth georeactor.
The estimated cost: $80 million. In an e-mail to The Chronicle, de Meijer said he is seeking funding from the Dutch government and industrial consortiums. He and his team plan to visit Curacao in January to take the geological samples needed to design the subterranean antineutrino "antenna," as they call it.
Curacao is a good location for the antineutrino detector because "the island's rocks have relatively few natural radionuclides that could mask the (antineutrino) signal from the Earth's core," the journal Physics World noted in September. The detector could be confused by antineutrinos emitted by commercial nuclear reactors, but Curacao is far enough from the southeastern United States that reactors in Florida won't affect it.
"Dr. Herndon is a brilliant and original thinker. I agree with his proposal" said geoscientist David Deming of the University of Oklahoma.
"The problem with most scientists working today is that they have no knowledge of the history of science," Deming adds. "As late as 1955, continental drift was regarded as the equivalent of alien abductions, Bigfoot and the Loch Ness monster. By 1970, continental drift was an accepted part of the new theory of plate tectonics."
Richard Muller, a noted physicist and author at Lawrence Berkeley National Laboratory in Berkeley. Since the 1970s, Muller has done pioneering research in diverse fields, including cosmology and planetary sciences.
"Herndon's discovery is a very positive contribution to deep Earth science. He raises issues that are worth exploring at some length. " Muller adds. "I consider his work to be 'out of the box' thinking, and as such, it is valuable as a step forward in our understanding of reality."
On a side note, in case you're wondering: Unlike the planet-busting reactor of Superman lore, neither the Gabon reactor nor Herndon's hypothetical deep-Earth reactors could explode like atomic bombs. A-bombs require highly concentrated amounts of fissionable materials that are explosively compressed together in a fraction of a second -- far faster than the snail's-pace processes that would be characteristic of the natural reactors.
Herndon received his bachelor's degree in physics at UC San Diego in 1970. He studied nuclear chemistry and meteorites in graduate school at Texas A&M, where he received his doctoral degree for a thesis on meteorites. Operating as an independent scientist, over the years, he has published papers in prestigious journals, including the Proceedings of the National Academy of Sciences and the Proceedings of the Royal Society of London. His main allies are non-Americans, like the de Meijer team. On Dec. 16, Herndon is scheduled to deliver the prestigious annual "Christmas Lecture" at the European Commission's Institute for Transuranium Elements in Karlsruhe, Germany. It is felt that the huge antinuclear bias in American society is preventing other U.S. academics from getting on board, as they might lose tenure positions or funding by bucking the strong academic antinuke culture on this issue. Had his two sons -- now physicians -- planned to become scientists, he says, "I would have steered them away from it because you can't make a living and do legitimate science; you have to 'howl with the wolves' or you don't survive. This is a sad testament to our times. There's something very wrong in American science."
Herndon’s proposal
According to traditional theory, the core of Earth consists of iron. The SanDiego scientist J. Marvin Herndon has argued that a large deposit of uranium also exists in the core, where it powers a natural nuclear reactor or “georeactor.” Herndon believes the nuclear process is responsible for variations in the intensity of Earth’s magnetic field.
During the radioactive decays, the georeactor releases ghostly particles called antineutrinos, which fly through thousands of miles of solid rock to Earth’s surface. Scientists will test Herndon’s georeactor by using special instruments to detect the antineutrinos as they pass through the outer crust.
Sources: nuclearplanet.com; www.ansto.gov.au/edu/about/about_neutron.htm;
Other scientists have expanded Herndon's proposal to include Thorium and Potassium.
nasa
http://sfgate.com/cgi-bin/article.cgi?f=/c/a/2004/11/29/MNGPIA17BL45.DTL
http://www.sciam.com/print_version.cfm?articleID=000B2C71-BCF0-1C71-9EB7809EC588F2D7
Why is the earth's core so hot? And how do scientists measure its temperature?
Jeff Atwell
Mount Vernon, Ohio
Quentin Williams, associate professor of earth sciences at the University of California at Santa Cruz offers this explanation:
There are three main sources of heat in the deep earth: (1) heat from when the planet formed and accreted, which has not yet been lost; (2) frictional heating, caused by denser core material sinking to the center of the planet; and (3) heat from the decay of radioactive elements.
It takes a rather long time for heat to move out of the earth. This occurs through both "convective" transport of heat within the earth's liquid outer core and solid mantle and slower "conductive" transport of heat through nonconvecting boundary layers, such as the earth's plates at the surface. As a result, much of the planet's primordial heat, from when the earth first accreted and developed its core, has been retained.
The amount of heat that can arise through simple accretionary processes, bringing small bodies together to form the proto-earth, is large: on the order of 10,000 kelvins (about 18,000 degrees Farhenheit). The crucial issue is how much of that energy was deposited into the growing earth and how much was reradiated into space. Indeed, the currently accepted idea for how the moon was formed involves the impact or accretion of a Mars-size object with or by the proto-earth. When two objects of this size collide, large amounts of heat are generated, of which quite a lot is retained. This single episode could have largely melted the outermost several thousand kilometers of the planet.
Additionally, descent of the dense iron-rich material that makes up the core of the planet to the center would produce heating on the order of 2,000 kelvins (about 3,000 degrees F). The magnitude of the third main source of heat--radioactive heating--is large, but quantitatively uncertain. The precise abundances of radioactive elements (primarily potassium, uranium and thorium) are is poorly known in the deep earth.
In sum, there was no shortage of heat in the early earth, and the planet's inability to cool off quickly results in the continued high temperatures of the Earth's interior. In effect, not only do the earth's plates act as a blanket on the interior, but not even convective heat transport in the solid mantle provides a particularly efficient mechanism for heat loss. The planet does lose some heat through the processes that drive plate tectonics, especially at mid-ocean ridges. For comparison, smaller bodies such as Mars and the Moon show little evidence for recent tectonic activity or volcanism.
We derive our primary estimate of the temperature of the deep earth from the melting behavior of iron at ultrahigh pressures. We know that the earth's core depths from 2,886 kilometers to the center at 6,371 kilometers (1,794 to 3,960 miles), is predominantly iron, with some contaminants. How? The speed of sound through the core (as measured from the velocity at which seismic waves travel across it) and the density of the core are quite similar to those seen in of iron at high pressures and temperatures, as measured in the laboratory. Iron is the only element that closely matches the seismic properties of the earth's core and is also sufficiently abundant present in sufficient abundance in the universe to make up the approximately 35 percent of the mass of the planet present in the core.
The earth's core is divided into two separate regions: the liquid outer core and the solid inner core, with the transition between the two lying at a depth of 5,156 kilometers (3,204 miles). Therefore, If we can measure the melting temperature of iron at the extreme pressure of the boundary between the inner and outer cores, then this lab temperature should reasonably closely approximate the real temperature at this liquid-solid interface. Scientists in mineral physics laboratories use lasers and high-pressure devices called diamond-anvil cells to re-create these hellish pressures and temperatures as closely as possible.
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