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It's official: An asteroid wiped out the dinosaurs

Discussion in 'International Forum' started by MziziMkavu, Mar 7, 2010.

  1. MziziMkavu

    MziziMkavu JF-Expert Member

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    AFP/File – Skeleton of a dinosaur is pictured on display at a Tokyo museum. Dinosaurs were wiped out by a huge asteroid … ​


    By Kate Kelland, Health and Science Correspondent
    Thu Mar 4, 2:07 pm ET

    LONDON (Reuters) – A giant asteroid smashing into Earth is the only plausible explanation for the extinction of the dinosaurs, a global scientific team said on Thursday, hoping to settle a row that has divided experts for decades.

    A panel of 41 scientists from across the world reviewed 20 years' worth of research to try to confirm the cause of the so-called Cretaceous-Tertiary (KT) extinction, which created a "hellish environment" around 65 million years ago and wiped out more than half of all species on the planet.

    Scientific opinion was split over whether the extinction was caused by an asteroid or by volcanic activity in the Deccan Traps in what is now India, where there were a series of super volcanic eruptions that lasted around 1.5 million years.

    The new study, conducted by scientists from Europe, the United States, Mexico, Canada and Japan and published in the journal Science, found that a 15-kilometre (9 miles) wide asteroid slamming into Earth at Chicxulub in what is now Mexico was the culprit.

    "We now have great confidence that an asteroid was the cause of the KT extinction. This triggered large-scale fires, earthquakes measuring more than 10 on the Richter scale, and continental landslides, which created tsunamis," said Joanna Morgan of Imperial College London, a co-author of the review.
    The asteroid is thought to have hit Earth with a force a billion times more powerful than the atomic bomb at Hiroshima.

    Morgan said the "final nail in the coffin for the dinosaurs" came when blasted material flew into the atmosphere, shrouding the planet in darkness, causing a global winter and "killing off many species that couldn't adapt to this hellish environment."

    Scientists working on the study analyzed the work of paleontologists, geochemists, climate modelers, geophysicists and sedimentologists who have been collecting evidence about the KT extinction over the last 20 years.

    Geological records show the event that triggered the dinosaurs' demise rapidly destroyed marine and land ecosystems, they said, and the asteroid hit "is the only plausible explanation for this."

    Peter Schulte of the University of Erlangen in Germany, a lead author on the study, said fossil records clearly show a mass extinction about 65.5 million years ago -- a time now known as the K-Pg boundary.

    Despite evidence of active volcanism in India, marine and land ecosystems only showed minor changes in the 500,000 years before the K-Pg boundary, suggesting the extinction did not come earlier and was not prompted by eruptions.

    The Deccan volcano theory is also thrown into doubt by models of atmospheric chemistry, the team said, which show the asteroid impact would have released much larger amounts of sulphur, dust and soot in a much shorter time than the volcanic eruptions could have, causing extreme darkening and cooling.

    Gareth Collins, another co-author from Imperial College, said the asteroid impact created a "hellish day" that signaled the end of the 160-million-year reign of the dinosaurs, but also turned out to be a great day for mammals.
    "The KT extinction was a pivotal moment in Earth's history, which ultimately paved the way for humans to become the dominant species on Earth," he wrote in a commentary on the study.

    (Collins has created a website at http://impact.ese.ic.ac.uk/ImpactEffects/Chicxulub.html which allows readers to see the effects of the asteroid impact.)
    (Editing by Myra MacDonald)

    http://news.yahoo.com/s/nm/20100304/sc_nm/us_dinosaurs_asteroid
     
  2. Kinyambiss

    Kinyambiss JF-Expert Member

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    Bado sisi..lol
     
  3. W

    Watanzania JF-Expert Member

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    Naomba utafsiri kwa ufupi hayo uliyoandika yana maana gani, Huyo mdudu kwenye picha ni nani? anaonekana wapi ili kujua kama mtu aweza kwenda kutalii na kumuona kwa macho, au aliwahi kuonekana wapi kwa macho na lini?
     
  4. K

    KipimaPembe JF-Expert Member

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    As it seems bigger bodies are liability. Miaka milion kadhaa ijayo this planet will only be inhabited by Bacteria and viruses as the only living beings. Mamoths and similar sized bodied animals all died out even after the speculated big bang by Asteroid.

    Evolution shows that bigger bodies are vulnerable to numerous ailments and troubles. So all big bodied beings are heading for extinction. The human brain will not help human surviving for long.
     
  5. Kinyambiss

    Kinyambiss JF-Expert Member

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    Ok, first of all dinosaurs did not die due to a "Big Bang" that is the common name used to described the explosion that occured 13.7 billion years ago leading to the creation of the universe and all matter (elements beginning with the heavy ones,hydrogen and helium and the rest by nuclear fusion, stars, galaxies, planetary systems and finally all organic life ie us, bacteria, plants etc).

    About the dinoursaurs, they were wiped out approximately 65.4 million years ago when a massive asteroid (left over from the creation of our solar system by the effects of gravity over billions of years). The size of the asteroid was the same as Mt. Everest and hit the planet somewhere in mexico causing a massive explosion that destroyed many species of animals and plants and made the sky go dark, stopping photosynthesis and creating a winter which finished off most life.

    We know this through geological studies which have shown a layer of rock and dust from 65million years ago contains a rare element that is found in asteroids in space..at the same time a crater was discovered in the waters near mexico.

    No one has ever seen a live dinosaur because they existed so long ago, few mammals existed and they were all the size of rats, living mainly underground (to escape the dinosaurs and that is how they survived the Cretaceous-Tertiary extinction...evolving over millions of years into us.

    That is a very simplified explanation of the a complex pre-historic event. Check this link for a general introduction to the life and history of dinosaurs.


    [ame]http://en.wikipedia.org/wiki/Dinosaur[/ame]

    their extinction
    http://en.wikipedia.org/wiki/Cretaceous%E2%80%93Tertiary_extinction_event
     
  6. K

    KipimaPembe JF-Expert Member

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    The big bang term I used was just a borrowed term. Sikuwa na maana kuwa big bang iliyotokeo zero seconds before the universe began.

    What I said is that dinos died out wholesale because of their large bodies. Why did other species survive and dinos died out? OK after dinos, other biggies came but later (without the asteroid knocking the world) they also went extinct. Dinos were reptiles, the cousins of today's lizards, crocks and snakes. And you can see for yourself that the biggies are giving way for smaller species, as it seems smaller is better.

    Mamoths were mammals. Mammals also have tried large body actecture, although as it is evident today, the actectue again is going to fail. The whales are now protected. Elephants are also dwindling. It is common today to blame human, but Mammoths died out without human interventions. Therefore as the world moves along the biosphere is evolving by removing big bodies for smaller bodied beings. There are Quadrilions of Quadrillions of living bacteria and viruses. And there are billions of rats in India alone dispite human efforts to kill them.

    Six billions humans already seem to be too much for the planet and they are now blamed for global warming and alot more environmetal problems facing the world today. We seem to forget that species has been facing extinction even when human populations were insignificant. today every species extinction is blamed on Humans.

    All living beings with big bodies will eventually give way to smaller and smaller beings, that's why I see a world full of bacteria and viruses 1 million or so years to come.
     
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