The breaking of the
sound barrier is not just an audible phenomenon. As a new picture from the
U.S. military
shows, Mach 1 can be quite visual.
This widely circulated
new photo
shows a Air Force
F-22 Raptor
aircraft participating in an exercise in the
Gulf of Alaska June
22, 2009 as it executes a supersonic flyby over the
flight deck
of the aircraft carrier USS John C. Stennis.
The visual phenomenon, which sometimes but not always accompanies the
breaking of the sound barrier
, has also been seen with
nuclear blasts
and just after
space shuttles
launches, too. A vapor cone was photographed as the Apollo 11 moon-landing mission
rocketed skyward
in 1969.
The phenomenon is not well studied. Scientists refer to it as a vapor cone, shock collar, or shock egg, and it's thought to be created by what's called a
Prandti-Glauert singularity.
Here's what scientists think happens:
A layer of
water droplets
gets trapped between two high-pressure surfaces of air. In humid conditions, condensation can gather in the trough between two crests of the sound waves produced by the jet. This effect does not necessarily coincide with the breaking of the
sound barrier
, although it can.
The aircraft carrier was participating in Northern Edge 2009, an exercise focused on detecting and tracking things at sea, in the air and on land.
Source and more details:
http://news.yahoo.com/s/livescience/20090630/sc_livescience/whatsupersoniclookslike