Skip to comments.Catastrophism
Posted on 04/02/2006 2:13:59 PM PDT by SunkenCiv
Did a planetary wobble kill the dinosaurs?Bruce Runnegar from the University of California at Los Angeles' Center for Astrobiology... and his colleagues used computer models to map out the Solar System for the past 250 million years. In particular, they looked at the perihelion of each planet - the point in its orbit where it is closest to the Sun. The perihelion of Earth rotates around the Sun with a period of hundreds of thousands of years. Because of subtle tugs and pulls between the planets, this period changes slightly with time... Their model suggests one of these blips significantly changed Mercury's orbit 65 million years ago. This wobble would have pulled at the asteroid belt, increasing the chances that asteroids in the Hungarias region would be knocked out of place. Now the researchers are running a fresh set of models to see how much the orbits of these asteroids changed. It wouldn't have been enough to send a shower of asteroids into the Earth, but Runnegar says the wobble could have sent a single asteroid onto collision course with our planet... Now he is planning to run his models forward in time, to see when the next potentially catastrophic planetary wobble will be.
by Nicola Jones
June 27 2001
Poles apart[T]he magnetic poles move more than 45° away from their original location and then return to it. During such "excursions", the field strength can vary enormously over just a few thousand years. "The magnetic field has lost half its strength since Roman times," says David Gubbins, a geophysicist at the University of Leeds... He thinks the fluid iron in the outer core is responsible for the excursions. The magnetic field changes in response to the flow of the liquid iron, which typically moves 10 or 20 kilometres per year.
by Charles Seife
10 April 1999
Geesh Louise! By the time I got through reading all this data the earth will have wobbled and it won't make any difference anymore.It's tremendously optimistic of you to think that it'll make any difference anyway. ;'D ;') ;')
Yeah, considering I still haven't even figured out why weebles wobble, but they don't fall down, I guess I am being a tad optimistic that my input will help any. :)
We're going on a planet hunt
EurekAlert | 04/05/06 | Claire Bowles
Posted on 04/05/2006 10:53:38 PM EDT by KevinDavis
Mercury's formation impact splattered Earth with materialNew computer simulations of Mercurys formation show the fate of material blasted out into space when a large proto-planet collided with a giant asteroid 4.5 billion years ago. The simulations, which track the material over several million years, shed light on why Mercury is denser than expected and show that some of the ejected material would have found its way to the Earth and Venus... "Mercury is an unusually dense planet, which suggests that it contains far more metal than would be expected for a planet of its size. We think that Mercury was created from a larger parent body that was involved in a catastrophic collision, but until these simulations we were not sure why so little of the planets outer layers were reaccreted following the impact, said Dr Jonti Horner, who is presenting results at the Royal Astronomical Societys National Astronomy Meeting on 5th April.
Royal Astronomical Society
April 05, 2006
Study finds two supermassive black holes spiraling toward collision
Eureka Alert | 6-Apr-2006 | Craig Sarazin
Posted on 04/06/2006 9:03:51 AM EDT by Pharmboy
Meet the Indian who took on Stephen Hawking
Rediff.com | August 03, 2004 10:06 IST | Rediff.com
Posted on 08/03/2004 1:16:56 AM EDT by CarrotAndStick
Giant Bubble Bullies Our Space
Space.com | 4/6/06 | Robert Roy Britt
Posted on 04/06/2006 8:51:08 PM EDT by NormsRevenge
Troubled Times/Discovering Archaeology | 8-1999 | Mike Baillie
Posted on 10/09/2005 7:25:36 PM EDT by blam
New Ice-Core Evidence Challenges the 1620s age for the Santorini (Minoan) Eruption
Journal of Archaeological Science, Volume 25, Issue 3, March 1998, Pages 279-289 | 13 July 1997 | Gregory A. Zielinski, Mark S. Germani
Posted on 07/29/2004 3:25:45 AM EDT by SunkenCiv
Aesthetic Meteorites Set for Auction
AP on Yahoo | 4/7/06 | Pat Milton - ap
Posted on 04/08/2006 1:30:52 AM EDT by NormsRevenge
Europe sets next phase in asteroid deflection project
AFP | Tue Apr 4, 2006
Posted on 04/10/2006 4:11:18 PM EDT by presidio9
Disaster That Struck The Ancients
BBC | 7-26-2001 | Fekri Hassan
Posted on 12/08/2001 5:51:43 PM EST by blam
(also the very first GGG thread)
Shouldn't that be "toast"? ;')Causes And Effects Of TheOccurrence in a previously recorded thick tephra deposit of particles identical to some of the mysterious layer and resemblance of its original pseudo-sand fabric with the exploded one of the mysterious layer confirms that the later is contemporaneous with the tephra deposit It has been however impossible to find typical tephra shards in sites located at a few km around the one with the tephra deposit The restricted occurrence of the later suggests that the massive tephra accumulation can no longer be considered as a typical fallout derived from the dispersion of material from a terrestrial volcanic explosion.
2350 BC Middle East Anomaly
Evidenced By Micro-debris Fallout,
Surface Combustion And Soil Explosion
by Marie-Agnès Courty
circa 1997Meteor clue to end of Middle East civilisations"Studies of satellite images of southern Iraq have revealed a two-mile-wide circular depression which scientists say bears all the hallmarks of an impact crater. If confirmed, it would point to the Middle East being struck by a meteor with the violence equivalent to hundreds of nuclear bombs. The catastrophic effect of these could explain the mystery of why so many early cultures went into sudden decline around 2300 BC. They include the demise of the Akkad culture of central Iraq, with its mysterious semi-mythological emperor Sargon; the end of the fifth dynasty of Egypt's Old Kingdom, following the building of the Great Pyramids and the sudden disappearance of hundreds of early settlements in the Holy Land."
by Robert Matthews, Science Correspondent
2001Comets, Meteors and Myth: New Evidence for Toppled Civilizations and Biblical TalesBiblical stories, apocalyptic visions, ancient art and scientific data all seem to intersect at around 2350 B.C., when one or more catastrophic events wiped out several advanced societies in Europe, Asia and Africa. Increasingly, some scientists suspect comets and their associated meteor storms were the cause. History and culture provide clues: Icons and myths surrounding the alleged cataclysms persist in cults and religions today and even fuel terrorism. And a newly found 2-mile-wide crater in Iraq, spotted serendipitously in a perusal of satellite images, could provide a smoking gun. The crater's discovery, which was announced in a recent issue of the journal Meteoritics & Planetary Science, is a preliminary finding. Scientists stress that a ground expedition is needed to determine if the landform was actually carved out by an impact... Archeological findings show that in the space of a few centuries, many of the first sophisticated civilizations disappeared. The Old Kingdom in Egypt fell into ruin. The Akkadian culture of Iraq, thought to be the world's first empire, collapsed. The settlements of ancient Israel, gone. Mesopotamia, Earth's original breadbasket, dust.
by Robert Roy Britt
13 November 2001
Reinventing Darwin Again:"The reason that Homo sapiens have survived in spite of these global disasters has little to do with the traditional explanations given by neo-Darwinists," said Benny Peiser, a social anthropologist at Liverpool John Moores University. "It is sobering to realize that we are alive due to cosmic luck rather than our genetic makeup."
How Asteroids Impacted Human Evolution
by Robert Roy Britt
24 April 2001
Peiser bases his argument on the fact that populations of hominids and early modern humans were extremely small. "Had any of these impacts occurred in the proximity of these population groups, we might also have gone the way of the dodo," he said.Is The Earth Due For Another Cataclysmic Impact?Current research on the history of cosmic catastrophes differs significantly between what might be called the British and the American schools of thought. Advocates of the American School are known for their cosmic 'optimism' and bordering on what critics have called cosmic 'naivite'. Their philosophy is characterised by a belief that giant impacts triggering global disasters happen very rarely (every 100,000 to 1,000,000 years on average) and that the flux of such impactors is more or less constant even over long periods of time. Cosmic impacts, according to this view, occur on a random basis mainly as a result of single asteroid impacts.
The Search For Past Impacts
Is Helping To Safeguard Our Future
by Benny Peiser
The American School is so convinced of their doctrine, that most of their advocates are not even interested in studying the historical or environmental records of humankind's more recent past.
The British School, by contrast, is more concerned with cometary debris which may have led to more recent punctuations. Although their focus on historical catastrophism makes them look like pessimists, their emphasis on empirical data and the notion that impacts often occur in clusters, may ultimately prove that they are actually cosmic realists.
Disaster that struck the ancientsProfessor Fekri Hassan, from University College London, UK, wanted to solve the mystery, by gathering together scientific clues. His inspiration was the little known tomb in southern Egypt of a regional governor, Ankhtifi. The hieroglyphs there reported "all of Upper Egypt was dying of hunger to such a degree that everyone had come to eating their children". Dismissed as exaggeration and fantasy by most other Egyptologists, Fekri was determined to prove the writings were true and accurate. He also had to find a culprit capable of producing such misery. He studied the meticulous records, kept since the 7th Century, of Nile floods. He was amazed to see that there was a huge variation in the size of the annual Nile floods - the floods that were vital for irrigating the land. But no records existed for 2,200BC. Then came a breakthrough - a new discovery in the hills of neighbouring Israel. Mira Bar-Matthews of the Geological Survey of Israel had found a unique record of past climates, locked in the stalactites and stalagmites of a cave near Tel Aviv. What they show is a sudden and dramatic drop in rainfall, by 20%. It is the largest climate event in 5,000 years. And the date? 2,200 BC.
by Jessica Cecil
Thursday, July 26, 2001
Leaking Earth could run dry
BBC | Wednesday, September 8, 1999
Posted on 04/12/2006 1:01:52 PM EDT by SunkenCiv
[from which, reprises follow]
Leaking Earth could run dryResearchers from the Tokyo Institute of Technology have calculated that about 1.12 billion tonnes of water leaks into the Earth each year. Although a lot of water also moves in the other direction, not enough comes to the surface to balance what is lost. Eventually, lead researcher Shigenori Maruyama and his colleagues believe, all of it will disappear... His figures, which he describes as conservative, suggest the leakage has caused sea levels to drop by around 600 metres in the last 750 million years. This trend has been largely obscured in the geological record by shorter-term variations in sea levels.
Wednesday, September 8, 1999Remains of an ancient oceanUntil 65 million years ago, a great ocean, the Tethys, separated India from Asia. There were no Himalayas and no Tibetan Plateau... A team led by Rob Van der Voo of the Department of Geological Sciences, University of Michigan, Ann Arbor, Michigan has found signs of this ancient ocean deep beneath the Indian subcontinent... By reconstructing the paths taken by earthquake waves through the Earth, they have created a three-dimensional computer model of the interior of the Earth beneath India and the surrounding area.
by Paul Cooper
26 August 1999Earth's Interior May Contain Oceans Of Water, Geologist SaysAs a rule, rocks on earth are quite dry -- much drier than meteorites, for example, which also contain wadsleyite. Earth rocks generally contain only a small fraction of 1 percent of water. Wadsleyite is about 3.3 percent water. That may not seem like much, but given the amount of wadsleyite scientists think is in the earth-- it could be three to five times the amount of all the surface water on the planet, Smyth said. "It's possible the earth has this way of regulating the amount of water on the surface," Smyth said... The earth's oceans have existed for at least four billion years, and have been fairly constant in volume over the last 500 million years. These "inner oceans" may play a role in regulating that supply, Smyth said. In 1996 Smyth also discovered wadsleyite II, which may store water under even greater pressures at a lower portion of the transition zone.
December 17, 1997Earth could hold more waterThere is already thought to be several oceans' worth of water slightly higher in the mantle, at a depth of around 400-650 km. This region is called the transition zone, as it is between the upper and the lower mantle. The lower mantle's minerals can retain about a tenth as much water as the rocks above, Murakami's team finds. But because the volume of the lower mantle is much greater than that of the transition zone, it could hold a comparable amount of water... Any hydrogen in the rocks presumably comes from trapped water, an idea that other measurements support. The researchers found more hydrogen than previous experiments had led them to expect.
by Philip Ball
8 March 2002Inner Earth May Hold More Water Than the SeasBased on what they witnessed in their lab, the researchers concluded that more water probably exists deep within the Earth than is present on Earth's surface -- as much as five times more... Murakami and his colleagues reached their conclusion based on how much water they managed to dissolve under the experiment's extreme conditions in several types of material that make up much of the lower mantle. They used heat and pressure -- 25.5 gigapascals of it, or more than 250,000 times natural atmospheric pressure at sea level -- to create four mineral compounds that exist in the lower mantle... Earth's oceans make up just 0.02 percent of the planet's total mass. T his means the vast lower mantle could contain many times more water than floats on the planet's surface.
by Ben Harder
March 7, 2002New Evidence Suggests Early Oceans Bereft Of Oxygen For EonsWorking with coauthor Timothy Lyons of the University of Missouri, the Rochester team examined samples from the modern seafloor, including the rare locations that are oxygen-poor today. They learned that the chemical behavior of molybdenum's isotopes in sediments is different depending on the amount of oxygen in the overlying waters. As a result, the chemistry of molybdenum isotopes in the global oceans depends on how much seawater is oxygen-poor. They also found that the molybdenum in certain kinds of rocks records this information about ancient oceans. Compared to modern samples, measurements of the molybdenum chemistry in the rocks from Australia point to oceans with much less oxygen.
March 5, 2004Did comets water Earth?Frank reports that he obtained pictures of nine small comets among 1,500 images made between October 1998 and May 1999 using the Iowa Robotic Observatory (IRO) located near Sonoita, Ariz. In addition, he says that the possibility of the images being due to "noise," or electronic interference, on the telescope's video screens was eliminated by operating the telescope in such a manner as to ensure that real objects were recorded in the images. This operation of the telescope utilized two simple exposure modes for the acquisition of the images. One scheme used the telescope's shutter to provide two trails of the same small comet in a single image, and the second scheme used the same shutter to yield three trails in an image.
University of Iowa news release
March 5, 2001
"In the two-trail mode for the telescope's camera, no events were seen with three trails, and for the three-trail mode, no events were seen with two trails," he says. "This simple shutter operation for the telescope's camera provides full assurance that real extraterrestrial objects are being detected."Did Comets Flood Earth's Oceans?The Ptolemy experiment on Rosetta may just find out... It is a miniature laboratory designed to analyse the precise types of atoms that make up familiar molecules like water. Atoms can come in slightly different types, known as isotopes. Each isotope behaves almost identically in a chemical sense but has a slightly different weight because of extra neutrons in its nucleii... By analysing with Ptolemy the mix of isotopes found in Comet 67P/Churyumov-Gerasimenko, he hopes to say whether comet water is similar to that found in Earth's oceans. Recent results from the ground-based observation of another comet, called LINEAR, suggested that they probably are the same... However, if the comets are not responsible for Earth's oceans, then planetary scientists and geophysicists will have to look elsewhere... If comets did not supply Earth's oceans then it implies something amazing about the comets themselves. If Ptolemy finds that they are made of extremely different isotopes, it means that they may not have formed in our Solar System at all.
European Space Agency
June 18, 2004When The Earth Dried OutAbout a billion years ago, the continents emerged relatively suddenly from an ocean that covered 95 percent of the Earth's surface, according to a new theory by Eldridge Moores, a geologist at the University of California, Davis. The appearance of large masses of dry land would have caused more extreme weather, changes in ocean currents and the emergence of proper seasons. In turn, these environmental changes may have led to rise in atmospheric oxygen that enabled the explosion of new life forms around 500 million years ago... In the early Earth, the ocean crust and the continental crust were much closer together in thickness, Moores said. That means that the difference between the height of the ocean floor and the height of the continents was much less. The oceans would have been much shallower, and the water would therefore have spread much further across the continents -- covering 90 to 95 percent of the planet's surface, instead of the present 70 percent. Many geologists agree with this scenario, Moores said. What is controversial is how quickly the Earth changed from a planet covered in water with a few mountainous islands to one with large continental landmasses. According to Moores' theory, the continents emerged quite suddenly, over about 200 million years... also implies that over time, the way plate tectonics works has changed.
February 11, 2002
STARS ESCAPE FROM ASTRONOMICAL ZOO
Thoth-l Volume VII-3 | 4/2/2003 | Don Scott
Posted on 05/03/2003 3:33:42 AM EDT by Swordmaker
Astronomers Report Finding a Solar System With Similarities to Ours
NY Times | May 17, 2006 | DENNIS OVERBYE
Posted on 05/18/2006 4:48:53 AM EDT by neverdem
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