mass extinction of life, including the dinosaurs, 65 million years ago at the end of the Cretaceous era (Shibley 93).But what would the effect be today if Earth was the target of an asteroid? If an asteroid the size of a kilometer or greater hit our Planet it would push the Earth over the threshold of global catastrophe. If such an impact occurred on land or in the oceans the results would alter the Earth's overall balance The impact would disperse dust globally, enough to produce a significant, short term change in climate worldwide. in addition to devastating blast effects in the region of impact. At the smaller end of the category 3 asteroid, the devastation would be immense. The larger end of the Category 3 spectrum, civilization itself would be threatened, if not wiped out altogether. The impact would first be accompanied by a massive explosion, enough to fragment and partially vaporize both the projectile and the spot below the impactor on the Earth'ssurface. For about a half an hour, the highspeed ejecta thrown from the impact wouldproduce enough searing heat to scorch every living thing around the impact and would create a firestorm from the heat and the falling fiery fragments, that would burn everything around – then spread rapidly over an entire continent. Many lakes, streams, soils, and the upper surface of some oceans would become acidified, as the nitric acid from the impactor's fireball entered the atmosphere and covered parts of the Earth's surface (Barnes-Svarney 57).The major problem would stem from the amount of dust and debris that entered the upper atmosphere. Such dust would be carried around the world by prevailing winds, the dust spreading and blocking out much of the sunlight. The sunsets and sunrises would take on an amazing ruddy glow but the dust would act like a screen during the day. The lack of sunshine would cause the temperatures to drop by tens of degrees Celsius which, according to climato...
