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To: E. Charters who wrote (94279)	3/30/2003 9:52:32 PM
From: Richnorth	Read Replies (1) \| Respond to of 116944

The Core truth - Earth really is losing its magnetic field It is happening 10 times faster than in the action flick; its strength could be halved in 1,000 years, letting in increased radiation THE Earth's core has inexplicably stopped spinning, causing a breakdown of the global magnetic field that has sheltered life from deadly solar and cosmic radiation for billions of years. Flocks of birds fly into buildings. People with pacemakers drop dead in the streets. Supercharged lightning batters the planet. The government mounts a desperate mission to tunnel more than 2,800 km into the Earth to jump-start the stalled core and restore the planet's magnetic shield before all life is extinguished. Okay, it's only a movie. It's called The Core. But how much of the sci-fi thriller is science and how much is fiction? 'It's far-fetched, but it's clever,' said Johns Hopkins University geophysicist Peter Olson, who recently watched the film. No mission - not even one led by a handsome geophysicist and a beautiful astronaut - could reach the Earth's core, he said, much less affect its motion. The deepest we have drilled to is 11 km. But the astonishing reality is that the Earth's protective magnetism really is weakening and it is happening 10 times faster than if the core had stopped spinning, as in the movie. Don't worry though. Here is what we know. The Earth has a spherical inner core of solid iron, about two-thirds the size of the moon. It is surrounded by an outer core of liquid iron - at 4,982 deg C. Between the core and us is 2,800 km of rock. Scientists believe a planet's magnetic field is sustained by the circulation of its liquid outer core. The liquid iron flows generally east to west, in a motion complicated by heat-driven convection and many eddies. The motion creates nature's equivalent of a dynamo - a sort of generator in which the rotating liquid sustains the magnetic field. If the core stops or solidifies, the field fades away, which has happened on Venus, Mars and Earth's moon. The magnetic force field that shields all life extends tens of thousands of kilometres into space. It deflects or captures atomic particles and dangerous radiation streaming from the sun, as well as cosmic rays from interstellar space. If Earth's core stopped spinning today, it could take 20,000 years for the magnetic field to die away, said Professor Olson. But 'what we actually see is a much more rapid decay than that', almost 9 per cent since German mathematician Karl F. Gauss first measured the field in 1835. At that rate - about 6 per cent a century - its strength would be halved in about 1,000 years. In The Core, the geomagnetic field unravels in months, causing special-effects havoc. Increased radiation from space and electrical changes in the atmosphere stop watches and melt suspension cables on the Golden Gate Bridge. Lightning bolts blast the Colosseum to rubble. It is all based on a particle of truth, said Prof Olson, 'but they took the actual phenomena as we currently understand them and exaggerated everything'. In real life, the loss of the Earth's magnetic field would have more gradual effects. If the field shut down today, solar particles and radiation would stream into the atmosphere, creating worldwide auroras of a kind now seen only near the Poles. More would penetrate to the ground. 'You would be exposed to more radiation,' said Prof Olson. Radiation injuries and genetic mutations would mount. Some say the atmosphere itself might erode and the planet would eventually become uninhabitable. The Earth's geomagnetic field has weakened substantially many times in the past 3 billion years, said Prof Olson. But it has always kept at least 10 per cent of its current strength and the hazard has always been brief, a few thousand years. It occurs with intermittent reversals in the direction of the field, when Earth's magnetic poles swop position - north to south, south to north. Geophysicists can read the timing, strength and direction of those ancient magnetic fields in old lava and sedimentary rock. By one count, 171 pole reversals have occurred in the past 71 million years. Over the past 5 million years, said Prof Olson, it has averaged once every 250,000 years. But intervals have ranged from thousands of years to millions. 'In a sense we are overdue,' he said. The most recent reversal occurred about 750,000 years ago - three times the average interval. On the other hand, 'the field could turn and start growing again'. Geophysicists believe the problem is the South Atlantic Anomaly. Mapped by satellites, it is a giant pothole in the magnetic field off the coast of Brazil. Spacewalking astronauts and satellites flying through it get higher doses of radiation. Prof Olson says the anomaly might mark an 'anti-dynamo' - a reverse eddy in the flow of molten iron far below. If the trend continues into the next century, the field could weaken 20 per cent. 'That's a little slow compared to the election cycle,' he said. So don't expect a government mission to get the core flowing smoothly again. Except in the movies. -- AP

To: E. Charters who wrote (94279)	3/31/2003 10:16:26 PM
From: DeplorableIrredeemableRedneck	Read Replies (1) \| Respond to of 116944

Charters you are a pain in the ass.

To: E. Charters who wrote (94279)	4/1/2003 6:24:03 AM
From: d:oug	Read Replies (1) \| Respond to of 116944

Fools Gold (or) The Art of a Bluff .................................................. Erica went on a safari in Greywacky, Northwest Territories, Canada. . He took his faithful pet dachshund along for company. . The dachshund starts chasing butterflies and notices a Wildcat heading rapidly in his direction, with intention of having lunch. . The dachshund thinks, "OK, I'm in deep trouble now! . Then he noticed some bones on the ground close by, and immediately settles down to chew on the bones with his back to the approaching Wildcat. . Just as the Wildcat is about to leap, the dachshund exclaims loudly, "Boy, that was one delicious Wildcat. I wonder if there are any more around here?" . Hearing this, the Wildcat halts his attack in mid-stride, a look of terror comes over him as he slinks away into the trees. "Whew," says the Wildcat. "That was close. That dachshund nearly had me." . A monkey who had been watching the whole scene from a nearby fig tree next to the Pinapple Thread bush, figures he can put this knowledge to good use and trade it for protection from the Wildcat. . So, off goes the monkey to find that Wildcat. . The dachshund saw the monkey heading after the Wildcat, and figured that something must be up. . The monkey soon catches up with the Wildcat, spills the beans and strikes a deal for himself with the Wildcat. . The Wildcat is furious at being made a fool of and says, "Here monkey, hop on my back and see what's going to happen to that conniving canine." . Now the dachshund sees the Wildcat coming with the monkey, and thinks, "What am I going to do now?" . Instead of running, the dog sits down with his back to these attackers, pretending he hasn't seen them yet... and just when they get close enough to hear, the dachshund says... "Where's that damn monkey? I sent him off half an hour ago to bring me another Wildcat." (or) Whom is afraid of the Big Bad Dug? d:o)g