How big must a space rock be to no longer be just a mesmerizing sight? What size is big enough to wreck a whole city? And what else does the damage depend on?
Simulator makes eerie prediction for what could happen if NASA mission fails dailystar.co.uk - get the latest breaking news, showbiz & celebrity photos, sport news & rumours, viral videos and top stories from dailystar.co.uk Daily Mail and Mail on Sunday newspapers.