Oct. 1, 2009— -- Bullets. Artillery. Horse whips.
For a time, they all could do something humans only dreamed of: travel faster than the speed of sound.
But in the mid-1940s, developments in aviation technology soared. And in 1947, fighter pilot Chuck Yeager became the first man to ever exceed Mach 1.
After Yeager's most famous flight, the military continued to break records in airspeed, even developing an aircraft that could travel six times the speed of sound. But it wasn't until years later that Mach-breaking technology moved beyond the military.
On Oct. 1, 1969, the Concorde 001, a joint British-French venture, traveled faster than the speed of sound for the very first time. It was the aircraft's 45th test flight and it held Mach 1.05 for 9 minutes at 36,000 feet and 75 miles from Toulouse, France.
It wasn't the first commercial aircraft to break the so-called "sound barrier." A few months earlier, the Russian Tupolev Tu-144 became the first commercial airliner to exceed the speed of sound. But unlike its competitor, the Concorde went on to have a relatively long life, carrying passengers across the Atlantic Ocean until it was retired in 2003.
"It was terrific," said Bob van der Linden, chairman of the aeronautics division at the Smithsonian's Air and Space Museum, who was a passenger aboard the Concorde's final flight.
Flying at Mach 1 is a little loud, he said, but otherwise it doesn't feel especially different from flying typical airliners.
And as for the entertainment?
"There is no movie," he said. Watching the plane pick up speed is thrilling enough.
"Everyone's eyes are glued to the Mach meter. As soon as it turns Mach 1, everyone applauds. At Mach 2, everyone applauds again," he said. "[Traveling] twice the speed of sound. That's just cool."
The hype surrounding Mach speeds and breaking the "sound barrier" started in the lead-up to and during World War II, said Peter Coen, principal investigator of the Supersonics Project at NASA's Langley Research Center.
The SR-71 Blackbird, which was developed in secrecy for the U.S. military during the late 1950s, is considered the fastest turbo jet powered plane. Developed for reconnaissance missions by Lockheed, the planes were designed to cruise at Mach 3.2 at altitudes up to 85,000 feet. The maiden Blackbird flight was Dec. 22, 1964. But it was retired in 1991, Coen said, as satellites overtook the Blackbirds' reconnaissance capabilities.
The sound barrier hasn't only been broken in the sky. On Oct. 13, 1997, Andy Green became the first to achieve an officially timed supersonic drive through a measured mile. The British jet car ThrustSSC made two Mach-breaking runs across Nevada's Black Rock desert at 759.333 mph and 766.109 mph respectively, according to CNN. The speed of sound was calculated that morning at 748.111 mph.