I had lunch with a friend a few days ago, and the conversation inevitably turned to what is happening in our body politic.

Until recently, I assumed that the term “extinction burst” referred to the impact of the comet, asteroid or other catastrophic space rock that wiped out the dinosaurs. Turns out the expression ...

Scientists at NASA and the University of Kansas say that a mass extinction on Earth hundreds of millions of years ago could have been triggered by a star explosion called a gamma-ray burst. The ...