The interstellar object (alternatively a comet or an asteroid) that killed the dinosaurs when it slammed into Earth didn't work alone. Researchers have shown previously that its after-effects, such as tidal waves and earthquakes, played an important role in the mass extinctions of three-fourths of plant and animal life. Now, new research suggests that one of the most important factors was the soot-rich smoke from fires sparked by the collision. Clay Tabor, a geoscientist at the University of Connecticut, and his colleagues studied soot, sulfates and dust to see how each type of particle may have contributed to the cataclysm....