Dust from the dino-killing impact ushered in years of global darkness (www.livescience.com)
About 66 million years ago, a city-size asteroid slammed into what is now the Yucatán Peninsula, ushering in a long period of darkness that snuffed out the nonavian dinosaurs. Researchers have long debated exactly what aspect of this event, known as the Chicxulub impact, caused the rapid change in climate. Was it sulfur...