Query requested via Raquel, 13 years outdated. IES Virgen del Carmen. Adra (Almeria)
The top of the dinosaurs got here all at once, when their lives had been minimize brief via the sight of a really perfect fireball that fell to Earth, inflicting an apocalypse from which the Mesozoic kings may no longer break out. Neither the tough chunk of the Tyrannosaurus rex nor the giant measurement of the sauropod Alamosaurus sanjuanensis (26 meters and 20 lots) may save those species from the crisis that loomed over them.
Essentially the most extensively authorised principle for the extinction of the Cretaceous-Paleogene boundary, often referred to as the Ok/T (Cretaceous-Tertiary) boundary, is a meteorite have an effect on about 10 kilometers in diameter that hit the Earth about 66 million years in the past. .
A cosmic twist of fate
An area rock (comet or asteroid) reached our planet at a velocity of a number of tens of kilometers in step with 2nd, with a damaging capability identical to 1 hundred million hydrogen bombs. It crashed in a shallow sea house that these days corresponds to the Gulf of Mexico and the Yucatan Peninsula in Mexico. It’s the so-called Chicxulub crater.
A game of the have an effect on that created Chicxulub Crater. POT
Because of this “cosmic accident” greater than part of the species was extinct. Some of the teams of organisms that disappeared had been dinosaurs, marine reptiles, ammonites (cephalopods with a big outer shell), crops, or even microorganisms.
Then again, it was once no longer the worst within the historical past of the Earth: for instance, the extinction on the finish of the Permian, about 252 million years in the past, eradicated at least 90% of species.
Anyway, dinosaurs are a distinct case. Even if its disappearance is related to the Ok/T boundary, within the closing 10 million years of the Cretaceous the collection of species has already reduced considerably because of a world cooling of about 7º C.
Moreover, they can’t be thought to be totally extinct, as birds are descendants of the theropod dinosaur crew. Subsequently, the target resolution to the query within the identify is that the dinosaurs didn’t totally disappear. They’re nonetheless amongst us.
Chronicle of a crisis
The meteorite will have to have crossed the ambience in a couple of seconds and produced a compression of the air in its trail that brought about a sonic explosion of unattainable dimensions. The air round that area rock will have to had been heated to 4 instances the temperature of the Solar.
The have an effect on produced a surprise wave that compressed the rock on Earth's floor and the meteorite itself so intensely that next decompression led to melting and vaporization of ash and steam.
Consistent with Walter Alvarez, a professor of geology on the College of Berkeley (California), it most certainly got here from a fireball of vaporized rock ejected via its personal force and warmth. It will have to have even crossed the higher prohibit of the ambience, earlier than falling again to Earth, masking it with a considerable amount of debris.
It’s estimated that the outlet created on the time of the collision was once about 40 km deep, but it surely instantly collapsed and widened and created a shallower crater with a diameter of about 175 km.
The have an effect on reached the world the place the limestone rocks had been virtually 3 kilometers thick. They, subjected to the prime temperatures of the surprise, launched massive quantities of CO₂ into the ambience with such a lot power that it will have to have dragged numerous rock fragments.
Hearth, mud and darkness
The destruction of all dwelling organisms was once absolute inside a radius of a number of hundred kilometers. In additional far away spaces, hundreds of kilometers away, the animals may see an enormous flash adopted via a surprise wave of compressed air, advancing at improbable velocity.
Then got here a cloud of fireplace and dirt at very prime temperatures that charred almost the whole thing, whilst the outside of the Earth propagated an earthquake of apocalyptic proportions, with waves of serious power and period.
A bath of rock fragments and molten chunks fell from the ambience, spreading warmth within the type of infrared radiation. The burning of wooded area lots darkened the sky with smoke, ash and soot, whilst atmospheric oxygen was once used up.
Waves a kilometer prime
The tsunami generated via the huge have an effect on most probably shaped waves as much as a kilometer prime that traveled around the present-day United States a number of thousand kilometers inland. Large channels dug into the ground of the Gulf of Mexico and sediments carried via massive waves had been discovered combined with fragments of molten rock ejected via the explosion.
Fewer debris than the ones thrown into the ambience via the explosion reached different extra far away spaces, which can be situated on different continents, and the frequency of fires will have to had been lower than in North The us. Then again, different fatal occasions additionally reached those areas, and is the reason why the mass extinction was once world.
Inside of a couple of weeks or months of the have an effect on, the fires would subside, the storm winds would subside and the tsunamis would lose their energy, however the setting and the Earth's floor had been cooled via the mud, ash and soot that slowly fell and blocked the passage of daylight.
The serious darkness lasted for a number of months, destroying the productiveness of photosynthesis that sustains meals chains via herbivores and predators.
acid rain is coming
When gentle returned, the local weather was excessively heat because of the huge quantity of greenhouse gases that had been launched into the ambience all the way through the have an effect on, the calcination of carbonates on which the meteorite fell, and a lot of fires. The extraordinary warmth lasted for centuries, till CO₂ ranges reduced.
Some other impact on the atmospheric stage was once acid rain and water poisoning with heavy metals. The heating that befell all the way through the have an effect on higher the temperature of the decrease portions of the ambience such a lot that the molecules of atmospheric nitrogen (N2) broke up and reacted with oxygen forming nitrogen oxide (NO) which, together with water vapor, results in the formation of nitric acid (HNO₃). This acid rain broken the crops and reacted with the rocks, poisoning the inland waters.
The unexpected disappearance of part of the plant and animal genera marked the tip of the Mesozoic Technology. It isn’t widely recognized why sure teams of organisms survived. Clearly, the huge dinosaurs, which require massive quantities of meals, weren’t some of the best-off. Then again, some kinds of chicken-sized dinosaurs additionally died out, and different reptiles, comparable to crocodiles, seemed.
Finally, the survivors discovered a special international stuffed with probabilities that preferred diversification and adaptation to new prerequisites, and thus the emergence of recent species, which is named evolutionary radiation. The surviving mammals and birds are some of the teams that experience ideal tailored to this new generation.
The interactive museum of the Parque de las Ciencias de Andalucia collaborates within the segment The Dialog Junior.
