Antarctic craters reveal strike The asteroid may have raised sea levels by up to 60cm Scientists have mapped enormous impact craters hidden under the Antarctic ice sheet using satellite technology. The craters may have either come from an asteroid between 5 and 11km across that broke up in the atmosphere, a swarm of comets or comet fragments. The space impacts created multiple craters over an area of 2,092km (1,300 miles) by 3,862km (2,400 miles). The scientists told a conference this week that the impacts occurred roughly 780,000 years ago during an ice age. When the impacts hit, they would have...