MASS EXTINCTIONS:
No 'Darkness at Noon' to Do In the Dinosaurs?
Richard A. Kerr
A geologist is questioning whether the dust from an asteroid impact really did in the dinosaurs after all. The impact still gets the blame, but other killing mechanisms--an obscuring acid haze, global fires and smoke, or a combination of mechanisms--may have done the dirty work. The finding, if it stands up, might help explain the seeming absence of other impact crises and reduce, at least marginally, the potential hazard to civilization if another massive body were to strike.