Sonic boom
posted on 23 Nov 2008 20:40 by hikari505Sonic boom
The term sonic boom is commonly used to refer to the shocks caused by the supersonic flight of an aircraft. Sonic booms generate enormous amounts of sound energy, sounding much like an explosion. Thunder is a type of natural sonic boom, created by the rapid heating and expansion of air in a lightning discharge.
When an object passes through the air, it creates a series of pressure
waves in front of it and behind it, similar to the bow and stern waves
created by a boat. These waves travel at the speed of sound, and as the
speed of the object increases, the waves are forced together, or
compressed, because they cannot "get out of the way" of each other,
eventually merging into a single shock wave at the speed of sound. This
critical speed is known as Mach 1 and is approximately 1,225 kilometers
per hour (761 mph) at sea level.
The sound of a sonic boom depends largely on the distance between the
observer and the aircraft shape producing the sonic boom. A sonic boom
is usually heard as a deep double "boom" as the aircraft is usually
some distance away. However, as those who have witnessed landings of space shuttles have heard, when the aircraft is nearby the sonic boom is a sharper "bang" or "crack". The sound is much like the "aerial bombs" used at firework displays.
SOURCE : http://en.wikipedia.org/wiki/Sonicboom
edit @ 23 Nov 2008 20:52:38 by hikari505
edit @ 24 Nov 2008 20:08:57 by hikari505