""Maybe we can better predict our own mass extinction that we're probably in the middle of," Gulick said." by Daniel Lawter via Phys.org Around 66 million years ago, an asteroid bigger than Mount Everest smashed into Earth, killing off three quarters of all life on the planet — including the dinosaurs. This much we know. But exactly how the impact of the asteroid Chicxulub caused all those animals to go extinct has remained a matter of debate. The leading theory recently has been that sulfur from the asteroid's impact — or soot from global wildfires it sparked — blocked out the sky and plunged the world into a long, dark winter, killing all but the lucky few. However research published Monday based on particles found at a key fossil site reasserted an earlier hypothesis: that the impact winter was caused by dust kicked up by the asteroid. Fine silicate dust from pulverized rock would have stayed in the atmosphere for 15 years, dropping global temperatures by up to 15 degrees Celsius,