When someone cracks a bullwhip, the sound that it makes, that cracking sound, is actually a mini-sonic boom because the tip of the whip if moving faster than the speed of sound. But did you know that the speed of sound in water is nearly four times greater than it is in the air? That's because the speed of sound depends on the density and the type of medium it's passing through.
So what about airplanes that move slower than the speed of sound? These planes create air pressure disturbances which move at the speed of sound, at a distance from the aircraft. The airflow has enough time to spread out and disperse the pressure disturbance. In these conditions, the sound of the plane will reach the observer before the actual plane comes into view. When the plane is flying at the same speed as sound, the pressure gathers together in front of the aircraft. The plane gets very close to the waves of pressure it is creating due to its high-powered forward thrust. "This causes a sudden and significant increase in drag, as the airflow has very little time to adjust, and gets compressed into a wall or barrier."
In the early 1930's, researchers focused their attention on the challenges that pilots faced as they tried to reach supersonic speeds. "Although other objects, such as bullets, cannon balls, and meteors were known to go faster than sound, it was highly doubtful whether an airplane or a person could stand the pressures of moving with such velocity. The US Air Force decided to put the theories to the test." And that perseverance finally paid off. For on 14 October 1947, Air Force Captain Chuck Yeager became the first man to successfully break the sound barrier. This one event paved the way for both human spaceflight and extraterrestrial exploration. By the end of the 1950's jet craft were routinely breaking this speed records.
Fast-forward 65 years to the day (14/10/2012) and another man, Felix Baumgartner, once again broke the sound barrier. But this time it was broken, not by a speeding jet, but by a falling human! Mr. Baumgartner jumped off a helium weather balloon suspended in the stratosphere, at a height of 128, 07 feet (24 miles or 38.6 km) straight up. After jumping, Felix remained in free fall for 34 seconds, which allowed him to break the speed barrier and set a speed record of 834 mph (1342 km). "This high speed was possible due to the low pressure and air resistance in the stratosphere." I can't even begin to imagine falling that fast through space!
I hope you enjoyed my little science lesson today...or refresher class for those of you who may have known this stuff already. Humans are capable of making magnificent contributions for the betterment of the world and its societies. But they are equally capable of causing immense destruction, too. I, for one, would like to think that all humans would want to make the world the best it can be. Maybe I'm naive, but I do try to always think the best about people.
I invite you back tomorrow, but until then I want to wish you all