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In its 4.5 billion - year being , Earth has been punch and gouged by hundreds of large asteroids that have slammed into its surface . At least190 of these collisionshave go away stupendous scratch that are still visible today . But not every space rock that zips into our planet ’s standard pressure relieve oneself it to the ground . So what does it take for anasteroidto make a dent on Earth , and which known encroachment events have left the self-aggrandizing volcanic crater ?
Most distance rocks that drum into Earth ’s atmosphere are n’t giant at all . They ’re very low — around 3 foot ( 1 metre ) across , harmonize to NASA . That ’s right for Earthlings , as any space rock less than 82 feet ( 25 m ) in diam usually wo n’t make it past Earth ’s atm , NASA report . The space rock ’s super mellow speeds heat up the gas in the atmosphere , which combust out the distance rock candy ( which technically becomes a meteor once it meets the atmosphere ) as it passes through . In most cases , any space rock leftover that makes it through the ambiance will cause little or no damage if it reaches the footing .
An illustration of an asteroid slamming into Earth. A space rock this size would leave an enormous crater.
" The atmosphere protects us from impacts , " at least in most face , Paul Chodas , director ofNASA ’s Center for Near Earth Object Studies at the Jet Propulsion Laboratory ( JPL ) in Pasadena , California , told Live Science .
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For example , a 56 - foot - wide ( 17 m ) meteor exploded over Chelyabinsk , Russia , in 2013 , creating a shock waving that transgress windows and caused injury . However , it did not make a volcanic crater , because the meteor did n’t really equal down , Live Science previously reported . The majority of it dissolved to rubble and tiny meteorites on the way , said Gerhard Drolshagen , a physicist who specializes in skinny - Earth object at the University of Oldenburg in Germany and the former director of the United Nations ' Space Mission Planning Advisory Group . A 5 - foot - blanket ( 1.5 G ) meteorite at the bottom of a nearby lake , as well as some smaller fragments , was all that remained , according to a reportfrom the forty-fifth Lunar and Planetary Science Conference in 2014 .
An illustration of an asteroid slamming into Earth. A space rock this size would leave an enormous crater.
But the 190 know impact craters on Earth ’s surface show that some bigger asteroids have made it through , though they have been far less common . Of those that have made terrestrial landing , most have concern down in North America ( 32 % ) , followed by Europe ( 22 % ) and Russia and Asia ( 16%),according to the Earth Impact Database .
Of theknown impact craters , 44 measure 12 miles ( 20 km ) across or declamatory . Here ’s what we have it off about the largest three to have hit either on land or piddle :
1 . The largest impact volcanic crater on Earth , the Vredefort crater in South Africa , is 99 miles ( 160 klick ) widely and was in all probability created about 2 billion geezerhood ago , concord toNASA ’s Earth Observatory . The crater has largely eat away , but establish on what ’s left of the flange , scientist have estimated that the asteroid that hit there was 6 to 9 mile ( 10 to 15 kilometer ) in diameter , Chodas said . " That ’s bigger than the one that killed thedinosaurs , but long before dinosaurs . "
For context , " it is expected that if an object is adult than 1 kilometer [ 0.6 miles ] , it could have spheric effects , " Drolshagen tell Live Science . So the asteroid that made the Vredefort crater was a catastrophic black eye , belike adequate to the one that kill the dinosaurs , Chodas said . " The encroachment would in all likelihood have caused fires all around the world , and a fantastic amount of dust would have been thrown up into the atmosphere " change the climate for months to age , he said .
2 . The Chicxulub crater on Mexico ’s Yucatan Peninsula is similar in size of it , at 112 miles ( 180 km ) astray , but much younger , NASA ’s Earth Observatory . It was created by a 7.5 - mile - broad ( 12 kilometer ) asteroid that hit Earth 66 million days ago . Though the volcanic crater is now partially on land , at the time of impact the Yucatan was under a shallow ocean . The collision led to the extinction of75 % of coinage , including the nonavian dinosaurs . The shock would have sent a " splash " of rock and debris into blank . Upon its return to Earth , the flame rubble likely torch much of the planet , Chodas said . The shock also would have created a dust cloud that enclose Earth for eld , stop sun and disrupting the food mountain range . The nonavian dinosaurs that did live the initial impact in all probability starve , Chodas pronounce .
3 . The Sudbury Basin in Ontario , Canada , rank third in sizing and , like Vredefort , is one of the oldest known impingement Crater on Earth . A 2014 cogitation in the journalTerra Novasuggested that perhaps it was n’t an asteroid that made the basin but rather a jumbo comet , or a jolting mix of asteroid morsel and ice . Somewhere between 6 and 9 miles in diameter , the space object struck Earth around 1.8 billion years ago .
Now , due to eroding , the volcanic crater is almost unrecognisable . But there is a flourishingnickelandironmining industry there . " What they are really mining is leftover asteroids , " Chodas say .
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Of the 44 largest craters on Earth that were formed from space stone impacts , 39 of the impacts occurred more than 10 million years ago , according to Earth Impact Database . The lone hand , Kara - Kul volcanic crater in Tajikistan , attain less than 5 million class ago .
" A circle of the big one are really old , because in the other days of thesolar arrangement , there was a lot more detritus vanish around and impacts were happening much more frequently , " Chodas said . " You see themooncovered with crater — the Earth would depend the same if it were n’t for ocean and erosions . " So there were in all probability many more asteroid impacts , and even bigger ones that we do n’t have records of , he said .
primitively published on Live Science .
