Liz MacDonald realized that if she wanted to create the world’s best aurora map, she needed a secret ingredient: Twitter.
The “pinball” model of a slipping fault line borrows from the mathematics of avalanches.
A surprisingly youthful estimate of the age of the rings has stirred a backlash.
A giant star’s death throes may offer the first evidence of a pair-instability supernova, and a glimpse of the first stars in the universe.