... thick flow, the lava is magnetized in the direction of the field prevailing at the moment of solidification. We would thus have a 2-week continuous record of the behavior of the earth's field. Ordinarily, we would not expect to see very much change in 2 weeks; even a reversing field is thought to take thousands of years to complete its flip-flop. However, at Steens Mountain, when the field reversed 15.5 million years ago, the lava flows suggest that the field's axis was rotating 3-8 per day -- incredibly fast according to current thinking, in fact a thousand times faster than expected. The conundrum (one might call it a scientific impasse) arises because the flowing electrically conducting fluids that supposedly constitute the earth's dynamo would have to flow at speeds of several kilometers/hour. No one has ever contemplated molten rock moving at such speeds in the core! (Appenzeller, Tim; "A Conundrum at Steens Mountain," Science, 255:31, 1992. Lewin, Roger; "Earth's Field Flips Flipping Fast," New Scientist, p. 26, January 25, 1992.) Could it be that the prevailing dynamo theory is incorrect? To make matters more interesting, it now seems that the paths taken by the reversing poles follow similar routes with each flip-flop. One preferred path is a band about 60 wide running northsouth through the Americas; the other path is 180 away cutting through east Asia and just west of Australia. The implication is that some unknown ...

... E . Morris review the evidence tying geomagnetic reversals to the impacts of large bodies with the earth: the tektites and microtektites; the climate changes; the biological extinctions, etc. Then they propose a physical mechanism for geomagnetic reversals: "The impact of a large extraterrestrial object on the Earth can produce a geomagnetic reversal through the following mechanism: dust from the impact crater and soot from fires trigger a climate change and the beginning of a little ice age. The redistribution of water near the equator to ice at high latitudes alters the rotation rate of the crust and mantle of the Earth. If the sea-level change is sufficiently large ( 10 meters) and rapid (in a few hundred years), then the velocity shear in the liquid core disrupts the convective cells that drive the dynamo. The new convective cells that subsequently form distort and tangle the previous field, reducing the dipole component near to zero while increasing the energy in multipole components. Eventually a dipole is rebuilt by dynamo action, and the event is seen either as a geomagnetic reversal or as an excursion." (Muller, Richard A., and Morris, Donald E.; "Geomagnetic Reversals from Impacts on the Earth," Geophysical Research Letters, 13:1177, 1986.) Comment. That the earth's field is generated by internal dynamo action is still a theory, although a widely accepted one. From Science Frontiers #49, JAN-FEB 1987 . 1987-2000 William R. Corliss ...

... a stop in the sky over one of these points and then moves backwards to the other point 180 away. As the sun tarries over these two spots, it heats them preferentially. The strange apparent motion of the sun is due to the 3:2 ratio between Mercury's period of revolution around the sun (88 days) and its axial spin period (59.6 days). What is surprising is that the energy detected radiating from the two hot spots is all reradiated solar energy; that is, there seems to be no contribution at all from Mercury's core! If no heat is leaking out of Mercury's core, the core itself is very likely solid. If it is solid, it cannot establish convection cells and thus generate a magnetic field through dynamo action. But back in 1975, the Mariner 10 spacecraft radioed back that Mercury actually does possess a magnetic field, and a surprisingly large one at that. (Wilford, John Noble; "Theory of Mercury's Hot Poles Is Shown to Be a Fact," New York Times, June 13, 1990. Cr. J. Covey.) Comment. Something is clearly awry. This inconsistency could mean that the dynamo theory presumed to be responsible for planetary magnetic fields is incorrect. Reference. Mercury's anomalous magnetic field is cataloged in section AHZ in our catalog: The Moon and the Planets. To order, visit: here . From Science Frontiers #71, SEP-OCT 1990 . 1990-2000 William R. Corliss ...

... Science Frontiers ONLINE No. 56: Mar-Apr 1988 Issue Contents Other pages Home Page Science Frontiers Online All Issues This Issue Sourcebook Project Sourcebook Subjects Large moon essential to the development of life?Even before its well known effect on romance, our moon was the key to the development of life on earth, according to J. Pearson. He ventures that our ponderous moon (much larger than the moons of Mars) was the key to the melting of the earth's core via tidal friction. With a fluid core, the earth developed a strong magnetic field (much stronger than those of the other inner planets) through dynamo action. This field protected nascent life from space radiation -- and here we are! (Hecht, Jeff; "Lunar Link with Life on Planets," New Scientist, p. 40, January 21, 1988.) Comment. Current scientific opinion declares that the moon was captured by the earth -- a rather rare astronomical event. The capture of a very large moon would be even rarer. From this shaky chain of thoughts, we conclude that life in the universe must be exceedingly scarce. However, such long chains of inferences are usually found to be far off the mark. From Science Frontiers #56, MAR-APR 1988 . 1988-2000 William R. Corliss ...

... Science Frontiers ONLINE No. 124: Jul-Aug 1999 Issue Contents Other pages Home Page Science Frontiers Online All Issues This Issue Sourcebook Project Sourcebook Subjects Magnetic Stripes On Mars As the Mars Global Surveyor swooped down to altitudes between 100 and 200 kilometers above the Martian surface during its aerobraking orbits, magnetometers detected broad, parallel stripes with alternating magnetic polarity. These stripes across the planet's southern highlands are a great surprise to planetologists because they superficially resemble the magnetic stripes that parallel the rifts along the floors of the earth's oceans where new crust is forming. The obvious implication is that Mars once possessed drifting continents and a geomagnetic dynamo that occasionally reversed its polarity -- just as has supposedly happened and is still happening on earth. Prior to this discovery, Mars was deemed too small to have possessed a heat-driven geodynamo, and there is no obvious surface evidence of drifting continents. Easy as it is to conclude that Martian continents once sailed ponderously cross the planet's surface, the scientific jury is still out. First of all, the Martian magnetic stripes are substantially different from earth's in shape, pattern, strength, and, above all, size. The Martian stripes are about 200 kilometers wide and 2,000 long -- much larger than earth's . Their magnetic field strength is more than ten times that of the terrestrial stripes. Whatever magnetic phenomena occurred on Mars some 4 billion years ago must have been quite different from what happened on earth 200 million years ago. Yet, no other reasonable explanation has been found for the ...

... the moment of inertia of the solid outer reaches of the Earth (crust and mantle) by a part in a million. 'That doesn't sound like much, Morris told us. 'But when we realized that this translates into a full radian of slippage between mantle and core in just 500 years, we began to look seriously at the consequences.' With the moment of inertia of the crust and mantle 'suddenly' decreased, the argument goes, they begin spinning faster than the solid-iron inner core at the center of the Earth. The 2300-km thick shell of liquid outer core that separates the mantle from the inner core thus acquires a velocity shear, which in the course of about a thousand years destroys the pattern of convective flows that served as the dynamo maintaining the Earth's dipole field." The field reversal is not immediate according to both calculations and analyses of sediments. After the impact event, the dipole field decreases for a few thousand years, followed by a longer hiatus. Then, there is a sudden reversal. (Schwartzschild, Bertram; "Do Asteroid Impacts Trigger Geomagnetic Reversals?" Physics Today, 40:17, February 1987.) Comment. In trying to relate all this to our present situation, recall that a major "ice age" is just a few millenia behind us, and our dipole field has been decreasing slowly for as long as we have been able to measure it. Brace yourselves! Reference. There are many anomalies associated with the tektites. See ESM3 in our catalog: Neglected Geological ...

... impressive data. They now find that the geomagnetic field probably shifted as much as 6 in a single day. Their work has been carried forward so professionally and meticulously that other scientists are finding their conclusions harder and harder to dismiss. Instead, the search is on for explanations of the rapid field changes. Three possibilities have been advanced -- all of them unpalatable to geophysicists: The Steens Mountain rocks are not faithful recorders of the main geomagnetic field. Should this be actually so, the whole field of paleomagnetism, including plate tectonics, is undermined, for it depends upon similar measurements. The earth's molten core can change rapidly, at least in some regions, in response to forces still unrecognized. This, of course, is not really a satisfying "explanation." The dynamo theory of the origin of the geomagnetic field is incorrect. (Coe, R.S ., et al; "New Evidence for Extraordinarily Rapid Change of the Geomagnetic Field during a Reversal," Nature, 374:687, 1995. Merrill, Ronald T.; "Principle of Least Astonishment," Nature, 374:674, 1995.) Reference. More puzzles of the geomagnetic field are provided in: Inner Earth. For details, visit: here . From Science Frontiers #101 Sep-Oct 1995 . 1995-2000 William R. Corliss ...

... unsynchronized propellers on a multi-engine aircraft.' When let outside the lookout station, the fire lookout's dog displayed anxiety, and the lookout felt barely perceptible vibrations under her feet when standing on a concrete slab. The lookout said she had heard the same sound during the summer of 1978, but always during the daylight." Colorado. Testimony of T. Adams: "Camping on the western slope of the Sangre de Cristos, northwest of Mount Blanca and south of the Sand Dunes, we heard the sounds in 1970. Two or three nights in succession, it 'cranked up' after midnight and subsided shortly before dawn. It wasn't really loud enough to hear over conversation - but definitely sounded like a motor of some sort, with a suggestion of a dynamo-type whine to it. And others had said that it sometimes seems even louder with an ear to the ground. One could easily imagine (Adam's emphasis) the sound was coming from beneath the surface, but whether it did or not remains purely speculative." The report referenced below contains similar observations from Texas, New Jersey, New York, Pennsylvania, California, Puerto Rico, England, and Ita ly. Unusual luminous phenomena have also been noted in the areas where the underground sounds have been heard, which explains why these phenomena were reported in a UFO publication. Some UFO investigators suspect that both the sounds and luminous phenomena are due to low-level seismic activity. (Long, Greg; "Machinelike Underground Sounds and UFO Phenomena," International UFO Reporter ...

... in the earth, in the other planets, and inside some of the stars. Don't worry that the Oklo phenomenon might occur today on the earth's surface. The concentration of fissionable U-235 has fallen considerably in the last 2 billion years due to its radioactive decay. But, deep inside the earth and other astronomical bodies, nuclear criticality might still be possible due to different pressures, densities, etc. In a stimulating and generally overlooked paper in Eos, J.M . Herndon proffers four important natural phenomena that may involve natural fission reactors. Geomagnetic reversals . In the deep earth, where pressures and densities are high, natural nuclear reactors may generate intermittent bursts of heat -- just as they did at Oklo -- and thereby cause the earth's dynamo to falter and reverse. Planetary heating . Jupiter, Saturn, and Neptune emit much more energy than they receive from the sun. Natural nuclear reactors could be the reason. Stellar thermonuclear ignition . Astronomers assume that the high temperatures required to ignite the thermonuclear reactions powering stars come from gravitational collapse, but this source does not seem adequate to some scientists. Nuclear fission reactors could ignite stars just as they do H-bombs. Missing matter . Natural nuclear reactors are finicky. There may be many star-sized, non-luminous objects out there that were never ignited and that we cannot see through our telescopes. (Herndon, J. Marvin; "Examining the Overlooked Implications of Natural Nuclear Reactors," Eos, 79:451, 1998.) Comments. Two additions to ...

... data about Jupiter itself and its four large Calilean satellites. These natural satellites have turned out to be a disparate bunch. Three have iron cores, but Callisto breaks the mold with an unusual core of mixed ice and rock. Europa probably possesses an ocean, and Callisto might also. Only one of Jupiter's large satellites, Ganymede, boasts a magnetic field. In fact, Ganymede is apparently the only satellite in the solar system to display an intrinsic, dipole magnetic field like the earth's . Although Ganymere's magnetic field is like that produced by a permanent bar magnet, its core is much too hot for permanent magnetism. Again like the earth, Ganymede's field is theorized to be generated by the convection of electrically conducting liquid in its core -- a dynamo of sorts. All well and good, but Ganymede is so small that it should have cooled off billions of years ago thereby freezing its metallic core. So then, whence its magnetic field? One way out of this box it to suppose that about a billion years ago Ganymede was circling Jupiter in an orbit that took it much closer to this ponderous planet. Then, Jupiter's powerful gravitational field would have gently kneaded Ganymede's structure creating what is called "tidal heating," which kept the core liquid and able to generate a magnetic field. (Johnson, Torrence V.; "The Galileo Mission to Jupiter and Its Moons," Scientific American, 282:40, February 2000.) Comment. Sounds good, but there is a puzzle piece missing: ...