Question: When was the sound barrier broken for the first time?
Disambiguated questions and answers: question: When may the sound barrier have broken for the first time by dinosaurs?
When was the sound barrier thought to be broken for the first time, but likely due to inaccurate ASI Readings?
When was the sound barrier broken for the first time by an unmanned missile?
When was the sound barrier broken for the first time, in a manned level flight?
answer: 150 million years ago
1942
3 October 1942
October 14, 1947
Natural Questions answer: 1947 (from the Wikipedia article "Chuck Yeager")