Readers dispute starfishes’ water-swirling abilities

Doomsday preppers

Dinosaurs and other creatures were largely wiped out 66 million years ago from an asteroid impact, volcanic eruptions or maybe a mix of the two, Thomas Sumner reported in “Devastation detectives” (SN: 2/4/17, p. 16), in the Science News special report “Dino Doomsday.”