EditorialIn a photo from Jack Lockwood/U.S. Geological Survey, a pointer bomb, which only had a small charge and was designed to emit smoke for targeting purposes, dropped on Mauna Loa in 1935, photographed in 1977 by Jack Lockwood, a Hawaiian Volcano Observatory geologist. (Jack Lockwood/U.S. Geological Survey via The New York Times)
EditorialThe bracelet, a cuff with spiky transducers, has 24 speakers that emit ultrasonic signals when the wearer turns it on, at the University of Chicago in Illinois on Feb. 13, 2020. (Petra Ford/The New York Times)