* Astronomy

Blobrana · L

RE: Dinosaur extinction

Blobrana · L

Scientists have unearthed a dinosaur bone dated to be 64.8 million years old, according to a study published online Jan. 26 in Geology.
The fossil is a femur bone of the sauropod species Alamosaurus sanjuanensis. The species is a herbivorous dinosaur that can reach up to 20 meters in length.
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Blobrana · L

Dinosaurs survived for at least 700,000 years after meteorite collision

Many palaeontologists believe that all non-avian dinosaurs disappeared almost 66 million years ago - after debris from the meteorite blocked out the sun and caused extreme climate conditions, killing vegetation worldwide.
But new tests on a fossilised bone of a plant eating dinosaur discovered in New Mexico found that it was only 64.8 million years old - meaning that it was alive about 700,000 years after it was thought to have died.
A team at the University of Alberta, Canada, used a new "direct-dating" method called U-Pb (uranium lead) dating to establish the age of a hadrosaur's thigh bone much more accurately.
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Blobrana · L

Scientists had previously identified the a giant Chicxulub crater in the Gulf of Mexico as the site of a single meteor strike thought to have obliterated prehistoric life on Earth.
But evidence for a second impact in Ukraine, dating back thousands of years before the Chicxulub impact, has raised the possibility that the dinosaurs may have been blitzed with a shower of meteorites
The Boltysh Crater in Ukraine was first discovered in 2002. But scientists have now unearthed a second cavity within the crater which they believe was caused by the aftermath of the Chicxulub impact - suggesting that the two meteor strikes occurred years apart as part of a wider "shower".
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Blobrana · L

The gigantic meteorite, which landed in the Yucatan peninsula in Mexico about 65 million years ago, killed off a lot of animals on its impact.
But it was the ensuing weather conditions that were responsible for the extinction of the dinosaurs, Université de Moncton professor Dr. Francis LeBlanc said in an interview.
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Blobrana · L

Giant asteroid wiped out the dinosaurs

A giant asteroid "about the size of the Isle of Wight" wiped out the dinosaurs 65 million years ago, according to a new study.
It slammed into Earth "faster than a speeding bullet", exterminating more than half of all species, say experts.
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Blobrana · L

Picture a dinosaur. Huge, menacing creatures, they ruled the Earth for nearly 200 million years, striking fear with every ground-shaking stride. Yet these great beasts were no match for a six-mile wide meteor that struck near modern-day Mexico 65 million years ago, incinerating everything in its path. This catastrophic impact - called the Cretaceous - Tertiary or K/T extinction event - spelled doom for the dinosaurs and many other species. Some animals, however - including many small mammals - managed to survive.
How did they do it?
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Blobrana · L

Geologist Walter Alvarez was on an expedition in Italy during the early 1970s when he noticed something fascinating in the limestone mountains outside Gubbio: two dark layers of rock sandwiching a lighter, half-inch-thick seam. The darker sections were filled with fossils of microorganisms known as forams, while the center swath was virtually devoid of fossil life. Alvarez and colleagues from Columbia Universitys Lamont-Doherty Earth Observatory later determined that the middle layer was laid down at the exact time of the extinction of the dinosaurs.
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Blobrana · L

The dinosaurs may have been wiped out by a meteor four times bigger than the one previously thought to have caused their extinction.
Scientists believe a 25-mile wide meteor crashed into the ocean off the west coast of India, creating the 310-mile wide Shiva basin.
Sankar Chatterjee of Texas Tech University and his team are now analysing the submerged basin, in the hope it will prove their theory.

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Blobrana · L

Scientists have discovered that dinosaurs may have died out 300,000 years after a giant meteor struck Earth.
It has long been theorised that a meteor strike caused the mass extinction of dinosaurs from our planet. It would not have been the actual impact, but rather the effects that would have killed them off: massive tsunamis, earthquakes, volcanic eruptions and a clouded atmosphere that would have altered the climate.

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