Comments: The phenomenon captured in the preceding images is a real, if not completely understood, aerodynamic oddity known as a condensation cloud.

Some scientists describe it as the visible manifestation of jet aircraft "breaking the sound barrier" (or creating a "sonic boom"). Others contend that these vaporous cones only form at "transonic" speeds (just under or over the speed of sound), may or may not be accompanied by a sonic boom, and strictly speaking have nothing to do with breaking the sound barrier. They are caused by a sudden drop in air pressure around the aircraft (see Prandtl-Glauert singularity).

In any case, all the preceding photographs appear to be authentic and show condensation clouds at the moment of their formation. I have confirmed the sources of five of the seven images, listed below with captions and credits corrected where possible:

Air Force Rockwell B-1B Lancer
"A USAF B1B makes a high speed pass very near the sound barrier at the Pensacola Beach, Florida airshow." July 12, 2002. Photo copyright Gregg Stansbery.


U.S. Navy F-18 Blue Angel
Image source unknown.


Navy Boeing F/A-18F Super Hornet
"The Super Hornet approaches the sound barrier. Due to the high humidity at Oceana the shock wave is clearly visible." September 25, 2004. Photo copyright Andreas Zeitler.


U.S. Navy F-18 Hornet Jet Fighters
"Lt. Col. William Chester Waldron, Commanding Officer of the Black Knights of Marine Fighter Attack Squadron Three One Four (VMFA-314) performs a supersonic fly-by." January 29, 2004. U.S. Navy photo by Chris M. Valdez.


U.S. Navy F-14B Tomcat
"An F-14B Tomcat assigned to the Swordsmen of Fighter Squadron Thirty Seven (VF-32) reaches the sound barrier during a low altitude supersonic fly-by." April 22, 2003. U.S. Navy photo by Justin S. Osborne.


U.S. Navy F/A-18 Hornet Jet Fighter
"An F/A-18 Hornet assigned to Strike Fighter Squadron One Five One (VFA-151) breaks the sound barrier in the skies over the Pacific Ocean." July 7, 1999. U.S. Navy photo by John Gay.


U.S. Navy F-14 Tomcat
Image source unknown.

Sources and further reading:

A Sonic Boom
NASA Astronomy Picture of the Day, 21 February 2001

The Prandtl-Glauert Singularity and Condensation
By M.S. Cramer, Gallery of Fluid Mechanics

F-14 Condensation Cloud in Action
By M.S. Cramer, Gallery of Fluid Mechanics

Ask the Experts: What Happens When an Aircraft Breaks the Sound Barrier?
Scientific American, 11 March 2002

Last updated: 05/02/06