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Did Comets Cause Ancient American Extinctions?Anne Casselman for National Geographic NewsMay 6, 2008 Debate has heated up over a controversial theory that suggests huge comet impacts wiped out North America's large mammals nearly 13,000 years ago. The hypothesis, first presented in May 2007, proposes that an onslaught of extraterrestrial bodies caused the mass extinction known as the Younger Dryas event and triggered a period of climatic cooling. The theory has been debated widely since it was introduced, but it drew new scrutiny in March at the annual meeting of the Society for American Archaeology annual meeting in Vancouver, Canada. Stuart...

WASHINGTON (Reuters) - Samples of rock dust retrieved from a comet called Wild 2 are forcing scientists to alter they way they think about these intriguing objects that streak through our solar system. A chemical analysis of the samples brought back to Earth by NASA's Stardust spacecraft showed that the comet is much more like an asteroid than scientists had expected. Comets are celestial bodies made of rock, dust and ice with characteristic tails of gas and dust streams that are formed in the solar system's distant, frigid reaches. A long-standing notion had been they were sort of a frozen...

For FReepers in the western US (& Hawaii), I have a heads-up for - potentially - a really nice meteor display early this coming Saturday morning. Points east will not be able to see the peak of the display because - at 4:36 AM PDT - twilight or daytime will already have occurred. The best show will be looking to the northeast. There will be a 3/4 full waning moon high in the sky, so if the observer can shield oneself from the moon behind an obstacle (phone pole, house, car, tree, etc.) the viewing will be improved. I was...

June 28, 2007 Comet theory collides with Clovis research, may explain disappearance of ancient people A theory put forth by a group of 25 geo-scientists suggests that a massive comet exploded over Canada, possibly wiping out both beast and man around 12,900 years ago, and pushing the earth into another ice age. University of South Carolina archaeologist Dr. Albert Goodyear said the theory may not be such "out-of-this-world" thinking based on his study of ancient stone-tool artifacts he and his team have excavated from the Topper dig site in Allendale, as well as ones found in Georgia, North Carolina and...

The so-called ‘Tunguska Event’ refers to a major explosion that occurred on 30 June 1908 in the Tunguska region of Siberia, causing the destruction of over 2000 km2 of taiga, globally detected pressure and seismic waves, and bright luminescence in the night skies of Europe and Central Asia, combined with other unusual phenomena. The ‘Tunguska Event’ may be related to the impact with the Earth of a cosmic body that exploded about 5–10 km above ground, releasing in the atmosphere 10–15 Mton of energy. Fragments of the impacting body have never been found, and its nature (comet or asteroid) is...

mammoth some 12,900 years ago. A team of two dozen scientists say the culprit was likely a comet that exploded in the atmosphere above North America. The explosions sent a heat and shock wave across the continent, pelted the ground with a layer of telltale debris, ignited massive wildfires and triggered a major cooling of the climate, said nuclear analytic chemist Richard Firestone of Lawrence Berkeley Laboratory, one of the scientists who presented the controversial new theory Thursday at a conference of the American Geophysical Union in Acapulco. At least 15 species, mostly large mammals including mammoths, mastadons, giant ground...

Comets and disaster in the Bronze AgeCosmic impact is gaining ground as an explanation of the collapse of civilisations, writes Benny Peiser At some time around 2300BC, give or take a century or two, a large number of the major civilisations of the world collapsed. The Akkadian Empire in Mesopotamia, the Old Kingdom in Egypt, the Early Bronze Age societies in Israel, Anatolia and Greece, as well as the Indus Valley civilisation in India, the Hilmand civilisation in Afghanistan and the Hongshan Culture in China - the first urban civilisations in the world - all fell into ruin at more...

The giant comet, known as 2000 CR105, measures some 400 kilometers across... Brett Gladman of the Observatoire de la Côte d'Azur in Nice, France, and his colleagues have discovered... that 2000 CR105 orbits the sun in 3175 years and never comes closer than 6.6 billion kilometers--well beyond Neptune's orbit. The farthest point of the highly eccentric orbit lies 58.2 billion kilometers from the sun--13 times as far as Neptune... One possibility is that 2000 CR105's orbit evolved into its freakish shape gradually, due to small, periodic gravitational nudges from Neptune. Computer simulations imply that such a "diffusive chaos" scenario is...

IRC+10216, also known as CW Leonis, was once a well-behaved main-sequence star as our own Sun is now... When astronomers turned the satellite toward IRC+10216 they discovered a substantial cloud of water vapor about 100 AU across. ("AU" --short for Astronomical Unit-- is a unit of length used by astronomers. One AU equals the mean distance between Earth and the Sun.) "There must be about four Earth-masses of frozen water around IRC+10216 to produce the vapor cloud we see," says Melnick. The water vapor probably does not come from the vaporization of oceans on an Earth-like planet, because there wouldn't...

The Stardust mission to bring back samples of comet and interstellar dust was more successful than they had hoped, scientists said yesterday. The 100-pound sample container from the seven-year mission, which landed on the salt flats of Utah on Sunday, captured thousands of particles, perhaps even a million, that originated at the edge of the solar system or from distant stars, they said. While they had expected mostly microscopic samples, the researchers said, a surprising number of the particles were large enough to be seen with the naked eye. "It exceeded all of our grandest expectations," Donald Brownlee of the...

COLUMBIA, S.C. - A supernova could be the "quick and dirty" explanation for what may have happened to an early North American culture, a nuclear scientist here said Thursday. Richard Firestone said at the "Clovis in the Southeast" conference that he thinks "impact regions" on mammoth tusks found in Gainey, Mich., were caused by magnetic particles rich in elements like titanium and uranium. This composition, the Lawrence Berkeley National Laboratory scientist said, resembles rocks that were discovered on the moon and have also been found in lunar meteorites that fell to Earth about 10,000 years ago. Firestone said that, based...

Houston Comets forward Sheryl Swoopes is opening up about being a lesbian, telling a magazine that she's "tired of having to hide my feelings about the person I care about." Swoopes, honored last month as the WNBA's Most Valuable Player, told ESPN The Magazine for a story on newsstands today that she didn't always know she was gay and fears that coming out could jeopardize her status as a role model. "Do I think I was born this way? No," Swoopes said. "And that's probably confusing to some, because I know a lot of people believe that you are." Swoopes,...

Although comets form at the frigid edges of the solar system, they appear somehow to contain minerals that form only in the presence of liquid water, and at much warmer temperatures, scientists are reporting today. On July 4, as planned, part of the Deep Impact spacecraft - essentially an 820-pound, washing machine-size bullet - slammed into the comet Tempel 1 at 23,000 miles an hour. The collision tossed up thousands of tons of ice and dust from the comet that were observed by telescopes on Earth as well as small flotilla of spacecraft. One of the observers was the Spitzer...

THUNDERBOLTS PICTURE OF THE DAYExploring the electric universe From ancient mythology to cosmic plasma discharge   homethe book quotes picture of the day picture archive subject index the film(video clips) products Contact usElectric Universe: Holoscience Electric Cosmos The Universe Dragon Science Plasma Cosmology Society for Interdisciplinary Studies     Jul 05, 2005Deep Impact?First ImpressionsThe Deep Impact was an amazing show, and there will be much more information to come.In advance of the event we set forth our expectations as explicitly as possible. Therefore, we urge readers of this page to refer to our previous Picture of the Day.We also...

WASHINGTON, July 4 -- NASA's Deep Impact spacecraft lived up to its name early Monday when it slammed into a comet with such force that the resulting blast of icy debris stunned scientists with its size and brightness. With the flyby stage of the two-part spacecraft watching from a safe distance, an 820-pound, copper-core "impactor" craft smashed into the nucleus of comet Tempel 1 at 23,000 miles per hour, sending a huge, bright spray of debris into space. "The impact was spectacular," said Dr. Michael A'Hearn of the University of Maryland, the projects principal scientist. "It was much brighter than...

THUNDERBOLTS PICTURE OF THE DAYExploring the electric universe From ancient mythology to cosmic plasma discharge Credit: NASA/JPL/UMD Artwork by Pat Rawlings the book quotes picture of the day picture archive subject index the film(video clips) products Contact usElectric Universe: Holoscience Electric Cosmos The Universe Dragon Science Plasma Cosmology Society for Interdisciplinary Studies     Jul 04, 2005Predictions on "Deep Impact"With the imminent arrival of the "Deep Impact" spacecraft at the comet Tempel 1, it is time to test competing theories on the nature of comets. The predictions and lines of reasoning offered here will set the stage for future...

WASHINGTON, June 27 - A two-stage spacecraft called Deep Impact is about to make an ambitious attempt to dissect a comet by slamming into it and blowing some of its innards into space for all to see. Launched from Florida on Jan. 12, NASA's Deep Impact is nearing the end of a finely calibrated 268-million-mile journey that puts comet Tempel 1 within its sights. An 820-pound copper-core "impactor" is to smash into the comet's nucleus at 23,000 miles an hour in the early hours of July 4, an unprecedented event that will, if all goes well, be witnessed by its...

On 26 May, JPL's unique orbital calculation software determined that Comet Catalina was on what could possibly be a collision course with Earth, though the odds of such an impact were small: just 1 chance in 300,000 of a strike on June 11, 2085. Based on the 980-metre size estimate, that would produce a 6-gigaton impact - equivalent to 6 billion tonnes of TNT. Astronomers expected the addition of further observations to the calculations to rule out any possibility of a collision, as happens with most newly-seen objects. But that did not quite happen. The comet's predicted pathway actually drew...

CAPE CANAVERAL, Fla. — A NASA spacecraft with a Hollywood name — Deep Impact — blasted off today on a mission to smash a hole in a comet and give scientists a glimpse of the frozen primordial ingredients of the solar system. With a launch window only one second long, Deep Impact rocketed away at the designated moment on a six-month, 268-million-mile journey to Comet Tempel 1. It will be a one-way trip that NASA hopes will reach a cataclysmic end on the Fourth of July. "We are on our way," an excited Michael A'Hearn of the University of Maryland,...

WASHINGTON, Jan. 10 - Since the earliest days of the solar system, comets have periodically smashed into Earth, blasting holes in the surface and scattering cosmic debris. Now it is our turn to strike back. On Wednesday, NASA is to launch a spacecraft called Deep Impact toward the comet Tempel 1. In six months, if all goes well, the craft will release an 820-pound copper-core "impactor" that will smash into the comet's nucleus at 23,000 miles per hour, excavating a crater that scientists say could be as large as a sports coliseum. Launching of the spacecraft from the Cape Canaveral...

Microscopic analysis, reported in the current issue of the journal Geology, revealed a 3-inch-thick layer of "shocked quartz" — a form of the mineral produced only under intense pressure like that of an impact — that dated to 35.5 million years ago, when a space rock slammed into the Earth about 120 miles southeast of present-day Washington.

IF IT had hit Central London, Britain would no longer have a capital city. The force of the meteorite that hit eastern Siberia last September destroyed 40 square miles of forest and caused earth tremors felt 60 miles away. An expedition from Russia's Kosmopoisk institute has only recently reached the site in a remote area north of Lake Baikal because of bad weather and difficult terrain, the Interfax news agency said yesterday. Fragments of the meteorite had apparently exploded into shrapnel 18 miles above the Earth with the force of at least 200 tonnes of TNT. At the time, Russian...

Members of a special expedition researching the site of the famous Tunguska meteorite fall have claimed they had discovered parts of an extraterrestrial device. The expedition, organized by the Siberian Public State Foundation “Tunguska Space Phenomenon” completed its work on the scene of Tunguska meteorite fall on August 9. It was the first expedition to the region since 2000. Guided by the space photos, the researchers scanned a wider territory in the vicinity of the Poligusa village for parts of the space object that crashed into Earth in 1908 and was later called the Tunguska meteorite. The scientists claim that...

Picture credit: TheCabal"I will never cower before any master nor bend to any threat"LINK TO THREAD TEN Iran seeks swap of Brits for suicide attackers Report says 40 Revolutionary Guard 'volunteers' held by UK Iran apprehended British military personnel and Navy vessels earlier this week in order to secure release of 40 "suicide operations volunteers" held by the UK, according to an Iranian Revolutionary Guard source. The source told the London Arabic-language daily Al-Sharq Al-Awsat that the British Army command in Iraq received the demand from the Revolutionary Guard, reported the Middle East Media Research Institute. According to the source,...

GREETINGS, FOLLOWING is a note re todays Alaskan quake. First a comment about this thread. SOME FREEPERS are fascinated with fringe areas of reality. Some of us even think the fringe areas of knowledge, research, anecdotal stories and the like will have very impactful effects on the WAR ON TERROR, WWIII, Biblical end time events etc. WE ALSO FIND FREEPERS FULL OF GREAT CREATIVITY OF THOUGHT, INSIGHT, WORK RELATED EXPERIENCES AND SKILLS ETC. useful in collecting diverse puzzle pieces and in analyzing them. This diversity is priceless and virtually unavailable on any other site. While we are seriously interested in...

Did comets flood Earth’s oceans? Did comets flood Earth's oceans? 16 June 2004 Did the Earth form with water locked into its rocks, which then gradually leaked out over millions of years? Or did the occasional impacting comet provide the Earth’s oceans? The Ptolemy experiment on Rosetta may just find out… The Earth needed a supply of water for its oceans, and the comets are large celestial icebergs - frozen reservoirs of water orbiting the Sun. Did the impact of a number of comets, thousands of millions of years ago, provide the Earth with its supply of water? Finding hard...

Comets to put on morning sky show By Dr David Whitehouse BBC News Online science editor Comet Bradfield passes the Sun Astronomers say there could be three comets visible to the unaided eye in the night sky in a few weeks' time. Comet Bradfield has just rounded the Sun and is heading for the dawn sky. It will be visible around 24 April. Comet Linear, too, is promising and should be seen at northern latitudes in the morning sky on about the same date. Finally, Comet Neat may be visible though experienced observers say it will be a week or...

The Mars rover Opportunity's examination of Martian rocks last week provided the first convincing evidence that our neighbour world was once "awash" in water, as one NASA scientist described it. But where did the water come from? And why does Mars have no liquid water now, while Earth apparently has been covered with the stuff for 4 billion years? Scientists are just beginning to piece the story together, and it goes right back to the beginning. Mars, like Earth, was formed from dusty and rocky debris left over after the sun was born 4.57 billion years ago. Initially, there were...

There's an old joke about the man who asks his neighbor to turn down the loud, raucous noise emitting from her stereo."What's the matter, are you a music hater?" "No," he replies, "I'm a music lover." I'm reminded of this by the calls of some over the years to end the space-shuttle program, even (perhaps especially) by people who are frustrated by our lack of progress in space. In the wake of the latest tragedy, the calls will undoubtedly grow louder, but in many cases, even if correct, they will be for the wrong reasons, and may not lead to...

How far up into the sky does the biosphere extend? Do microorganisms exist at heights of 40 km and in what quantity? To answer these questions several research institutes in India collaborated on a path-breaking project to send balloon-borne sterile "cryosamplers" into the stratosphere. The programme was led by cosmologist Professor Jayant Narlikar, Director of the Inter University Centre for Astronomy and Astrophysics in Pune, with scientists at the Indian Space Research Organisation and the Tata Institute of Fundamental Studies contributing their various expertise. Large volumes of air from the stratosphere at heights ranging from 20 to 41km were collected...

Comets, Meteors & Myth: New Evidence for Toppled Civilizations and Biblical Tales By Robert Roy Britt Senior Science Writer posted: 07:00 am ET 13 November 2001 "...and the seven judges of hell ... raised their torches, lighting the land with their livid flame. A stupor of despair went up to heaven when the god of the storm turned daylight into darkness, when he smashed the land like a cup." -- An account of the Deluge from the Epic of Gilgamesh, circa 2200 B.C. If you are fortunate enough to see the storm of shooting stars predicted for the Nov. 18...

Comet's debris promises celestial light-show Earth is about to plough through a thick cloud of comet dust giving sky watchers a celestial treat. The Perseid meteor shower, which puts on a display at this time every year, is now approaching its maximum intensity. It will peak tomorrow, sending shooting stars blazing trails across the sky at a rate which could reach two a minute. This year's Perseid show should be a good one because there will be virtually no moon, and the meteor numbers are expected to be higher than usual. The Perseids, which have mystified and terrified people for...

August 2, 2002 | A comet first seen by a German amateur astronomer in July, then lost for five days, is about to become an easy target for small telescopes in the Northern Hemisphere. The nearly tailless object looks like a fuzzy, 10th-magnitude star, slowly making its way from Andromeda into Cassiopeia. It should brighten to 9th magnitude by mid-August as it enters the north circumpolar sky, then remain this bright through September while turning south across Ursa Major. It was shortly after midnight on July 22nd that Sebastian Hoenig of Dossenheim, Germany, found himself unable to sleep. So he...

Astronomy Picture of the Day Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2002 July 24 Our Busy Solar System Credit & Copyright: MPC, CBAT, Harvard CfA, IAU Explanation: Our Solar System is a busy place. Although the major planets get the most press, a swarm of rocks, comets, and asteroids also exist. The above plot shows the placement of known inner Solar System objects on 2002 July 20. The light blue lines indicate the orbits of planets. The green dots...

Did Asteroids and Comets Turn the Tides of Civilization? By Mike Baillie The heart of humanity seems at times to have lost its cadence, the rhythmic beat of history collapsing into impotent chaos. Wars raged. Pestilence spread. Famine reigned. Death came early and hard. Dynasties died, and civilization flickered. Such a time came in the sixth century A.D. The Dark Ages settled heavily over Europe. Rome had been beaten back from its empire. Art and science stagnated. Even the sun turned its back. "We marvel to see no shadows of our bodies at noon, to feel the mighty vigor of...