U.S. Dept. of Defense:
A hypersonic weapon moving at five times the speed of sound can travel across the Pacific Ocean in just over 100 minutes.
U.S. adversaries are developing such weapons now, said Michael D. Griffin, undersecretary of defense for research and engineering.
“They are quite capable,” Griffin said. “The advantage offered by a hypersonic offense is that it overflies air defenses as we understand them today, and it underflies our missile defenses. It goes into the gap between air defense and missile defense.”