The Sound You Feel in Your Chest

When SpaceX launched the Falcon Heavy from Kennedy Space Center in February 2018, spectators gathered at viewing sites six miles away. They watched the twin boosters ignite in silence — light travels faster than sound. Then, roughly thirty seconds later, the sound wave arrived. It didn't just reach their ears. It hit their chests. Observers described feeling their ribcages vibrate, their jacket zippers rattle.…