Dust from the asteroid impact was blown into the atmosphere where it blocked out the sun and led to the extinction of 75% of life, including all non-avian dinosaurs.

This shows a sloth at the forest edge. This image relates to a paper that appeared in the July 13, 2012, issue of Science, published by AAAS. The paper, by Dr. O.R. Wearn at Imperial College London in ...

Humans have been shaping their environment since time immemorial. From cities to farms to highways, our impact has grown so large that we've pushed planetary boundaries, fueling concerns about climate ...