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Sunday, May 27, 2012

The Largest impact craters that have beaten the Earth


Imagine staring at the sky, which gradually gets closer, more and more closely. That point doubling in size every second, to darken the sky. His entry into the atmosphere is accompanied by light and heat, the giant rock wrapped in a meteor full of death that goes directly to you. 
It sounds like the introduction of a catastrophic film, however not very far from reality as these impacts ended the lives of potential witnesses to the event in his time, leaving only the record of their impact on Earth's surface. Today we will show the largest impact craters that have impacted the Earth. In ascending order according to their size, see:



1. Barringer Crater, Arizona, U.S. 
This crater was once called Devil's Canyon (Canyon Diablo Crater) and the meteorite that created the crater is officially called the Canyon Diablo meteorite, a name can be found in all official labeled fragments of the meteorite. Scientists often refer to it as Barringer Crater in honor of Daniel Barringer, who was the first to suggest that the crater was the result of a meteorite impact. It is estimated that the impact that created the crater occurred about 50,000 years ago during the Pleistocene period, when the climate of the Colorado Plateau was much cooler and wetter. Most of the meteorite was vaporized. It measures 0.75 miles (1.2 km) wide, is 575 feet (175 m) deep and has a rim 148 ft (45 m) above the surrounding plain. 



2. Bosumtwi, Ghana, West Africa 
Bosumtwi, situated within the crater of an ancient meteorite impact, consists of about 8 kilometers in diameter and is the only natural lake in Ghana. It lies about 30 km southeast of Kumasi and is a recreational area. There are about 30 villages near the lake, with a combined population of over 70,000 people. The Ashanti consider Bosumtwi a sacred lake. According to traditional beliefs, the souls of the dead come here to bid farewell to the god Twi. Because of this, is admissible only fish in the lake on wooden planks. 



3. Deep Bay, Canada 
Located near the southwestern tip of Reno Lake in Saskatchewan, Canada. In a complex structure fully submerged and low central uplift is believed to have been formed some 100 million years (some say 140 million), when a large meteorite crashed in the area. It has about 13 km wide (8 miles) and consists of a very deep lake and irregular. 






4. Aorounga Impact Crater, Chad, Central Africa 
Aorounga is a crater caused by a meteorite impact that formed 345 million years in an area of ​​the Sahara Desert, northern Chad, in Africa. It is estimated that a comet or an asteroid with a diameter of 1 mile (1.6 km across) hit the Earth's crust. These impacts occur only about once every million years. 

The crater is about 11 miles (17 km) wide and is accompanied by two circular features that were revealed by SIR-C radar space shuttle, with an area of ​​about 22 miles (36 km). If the hypothesis is correct, the dark band in the upper right corner could be a second impact crater, or failing that, Aorounga can be part of a chain of multiple impact craters. 




5. Gosses Bluff, Australia 
Approximately 142 million years ago, a large asteroid or comet about 22 km in diameter, crashed at 40 km / sec in the southern Northern Territory, near the center of Australia, and released a large amount of energy equivalent to 22,000 megatons of TNT. One of the most significant impact structures of the world, the crater Gasses Bluff. The dimensions are impressive: it has about 15 miles (24km) in diameter and an estimated depth of 16,400 feet (5,000 m). Its impact is only a distant memory because its surface is badly eroded. 






6. Mistastin Lake, Canada 
Located in Labrador, Canada, Mistastin crater is the result of a crash of a meteorite that caused a giant hole about 28 km wide (17.4 miles), 38 million years ago. Since then, the eastward movement of the glaciers has drastically reduced their size and causing the appearance of the wheels and the lake that bears his name. It occupies an elliptical depression, tending east-northeast, roughly about 11 by 7 miles in size. In the middle of the lake, there is an accurate central island which could be the central uplift of a complex structure of the crater. 



7. Clearwater lakes, Canada 
Are a pair of circular lakes in the Canadian Shield in Quebec, Canada, near Hudson Bay. The lakes are actually one body of water dotted with islands that form a "dotted line" between eastern and western parts. The name comes from the clear water it contains. It is believed corresponds to the impact of an asteroid pair which crashed for about 290 million years ago, near the east coast of Hudson Bay. The larger of the two craters is West Clearwater Lake with a diameter of about 32 km (20 miles), while the smaller, east of Clearwater Lake has a diameter of about 22 km (13.7 miles). The objects hitting gravitation ally bound state could do a binary asteroid, a suggestion first made Thomas Wm. Hamilton in a letter of 1978 to the magazine Sky & Telescope. 



8. Kara-Kul, Tajikistan 
At an altitude of 13,000 feet (3,900 m) above sea level lays Kara-Koll, also known as Kara-kul: is an endorsees lake of 25 km in diameter in the Pamir Mountains in Tajikistan. A peninsula projecting from  the Southern shore and an island in the north, dividing the water into two basins. The east is shallow, 13 to 19 meters, but in western background is more than 200 meters. The impact occurred about 5 million years. Kara-Koll was discovered only recently, through satellite imagery. 





9. Manicouagan, Canada 

Manicouagan Lake (Lake Manicouagan) also known as the "eye of Quebec" is an annular lake located in central Quebec, Canada, and corresponding to the eroded remains of an ancient crater, due to the impact of an asteroid 5 km in diameter, dug a hole about 100 km in diameter. Today the crater diameter was reduced to 72 miles due to erosion and sedimentary processes. Recent research has shown that the crater has an age of about 214 million years, however, this impact could not be the cause of mass extinction of Triassic-Jurassic. 


10. Chicxulub, Mexico 
Buried underneath the Yucatán Peninsula in Mexico near the village of Chicxulub (meaning "tail of the devil" in Mayan), measures more than 180 kilometers in diameter, forming one of the largest impact in the world; it is estimated that the bolides that formed the crater was at least ten kilometers in diameter. The impact occurred about 65 million years ago when a comet or an asteroid the size of a small city crashed into the Earth causing a destructive force equivalent to 100 treason of TNT, causing destructive mega-tsunamis, earthquakes and volcanic eruptions around the world. 



The other corresponds to Doltish crater, discovered in 2002 by a group of researchers from the University Of Aberdeen, UK. The finding of a second crater in Ukraine suggests that dinosaurs became extinct by the dual impacts rather than one as previously thought.

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