(Before It's News)
What would be the environmental effects if the earth collided with a large comet? For instance, what would the climate be like afterward, and what forms of life would be most likely to survive?
Gerrit L. Verschuur, an astrophysicist and radio astronomer at Rhodes College in Memphis, Tenn., has been investigating this topic.
“A collision between a comet and the earth would be a calamitous event. Based on the best available computer simulations, the impact of an object a kilometer or more in size would probably trigger the end of civilization. Such a body might not wipe out our species, but if the incoming object were more than about five kilometers across, it is very unlikely that Homo sapiens would survive.”
Watch the video: What would Really Happen if the Earth Collided with a Large Comet?

“Broadly speaking, the initial impact creates a vast fireball that kills anyone who can see it. In the aftermath, ejecta (material hurled into the air) from the impact blasts into space and showers a large area–half of the world, perhaps–with flaming debris. (Something like this was seen when Comet Shoemaker-Levy 9 collided with Jupiter in 1994.)”
“The sky becomes filled with gazillions of meteors, a shower of particles that burn up in the atmosphere on their way down. It is as if the sky itself has caught fire. The heat unleashed by this rain of incandescent debris ignites forests and cities, burning them to embers.”
“Then dust from the impact and smoke from the fires girdles the earth, plunging our planet into a so-called impact winter. (Again, a similar effect was seen on Jupiter, where huge black bruises appeared after each fragment of Shoemaker-Levy struck.) Sunlight completely disappears for a month or so after a collision with a one-kilometer object; a 10-kilometer object might block out the sun for a year or more. “