Trisha+Peterka

= Supersonic Jet with Cloud Phenomenon = A jet can travel up to speeds faster than sound. This is referred to as supersonic speeds. Pictured above is the Commanding Officer of the Marine Fighter Attack Squadron Three One Four (VMFA-314) as he performs a supersonic fly by. When traveling at supersonic speeds, a jet is actually traveling in front of the sound which it produces. Thus someone watching the jet fly by them will not hear the jet until it passes them. A cone shaped shock wave is produced.

The interesting white cone shaped cloud is related to this sound cone phenomenon. As the jet travels, it creates a sound cone as well as creating a high pressure area in front of the jet. The air gets pushed or concentrated at the front of the jet, creating an area of low air pressure just to the middle of the jet. If the conditions are just right, a halo or egg shaped cloud sometimes forms. Although the origin of this cloud is still debated, many scientists believe it has to do with the drop in air pressure at the plane. There is less air pressure just behind the cone, at the jet, thus moist air condenses to form water droplets around the jet. These halos of vapor can appear very briefly when aircraft reach speeds just above or just below the speed of sound, and when weather conditions are favorable as well.

__**Physics Topic Catagories**__Sound, Speed, Weather

__**References**__Darling, David. "Sonic Boom." //The Worlds of David Darling//. 10 July 2010. Web. 11 Oct. 2010. ."NASA - NASA Dryden Fact Sheet - Sonic Booms." //NASA - Home//. Ed. Marty Curry. 1 Mar. 2008. Web. 11 Oct. 2010. .http://videos.howstuffworks.com/nasa/2215-how-sonic-booms-work-video.htmhttp://antwrp.gsfc.nasa.gov/apod/ap070819.html