Did You Hear the Sonic Boom?  what is Sonic Boom? “Sonic booms are created by air pressure. Much like a boat pushes up a bow wave as it travels through the water, a vehicle pushes air molecules aside in such a way they are compressed to the point where shock waves are formed.”"These shock waves form two cones, at the nose as well as at the tail of the vehicle. The shock waves move outward and rearward in all directions and usually extend to the ground. As the shock cones spread across the landscape along the flightpath, they create a continuous sonic boom along the full width of the cone’s base. The sharp release of pressure, after the buildup by the shock wave, is heard as the sonic boom.”

The Space Shuttle Endeavour touched down at Edwards Air Force Base Sunday afternoon at around 1:25 p.m. on runway 04-left at Edwards Air Force Base. It had been scheduled to land at the Kennedy Space Center in Florida but because of inclement weather was diverted to Edwards. High winds and possible thunderstorms at Cape Canaveral prompted the route change for the shuttle, whose seven-person crew had been servicing the International Space Station for two weeks in preparation for larger crews on longer missions, NASA officials said.  

 Approaching Edwards Air Force Base in rural Los Angeles County at 235 mph, the shuttle touched down at its expected time of 1:25 p.m., producing two sonic booms as it broke the sound barrier. The sonic booms that arrived a few minutes before the landing were heard across the county and startled some residents who called the Los Angeles Fire Department because of what they thought were explosions.

Endeavour is the first shuttle to land at Edwards since June 2007, when Atlantis set down.