Why does a jet look like this when it breaks the sound barrier?

[QuantumTheory]

This pic is really cool, it looksl ike a cloud. I'm only 17, so don't know much physics, i hope someone can explain this in an easier way. Why does it look like a cloud

 

[Danger]

It is a cloud. The pressure change from supersonic flight can cause moisture to condense out of the air if conditions are right. Take a look a some of the links in the 'sonic boom question' thread.

 

[enigma]

I'll guess that it's because there is a rapid pressure drop which causes the moisture in the air to condense.

 

[Astronuc]

See links here - https://www.physicsforums.com/showthread.php?t=101281

The air is compressed at the shock boundary and then expands rapidly behind the shock wave, cooling it off, and condensing the water vapor.

 

[Pengwuino]

there's a somewhat widespread video of a jet doing a supersonic flyby of an aircraft carrier and you can see the cloud forming.

 

[Clausius2]

I remember to have questioned the same:

https://www.physicsforums.com/showthread.php?t=45265&highlight=Sound+barrier

 

[ranger]

That pic looks great for something moving at the speed of sound! How would one photograph something like this?

 

[russ_watters]

There really isn't anything special about taking a picture like that - people take pictures of planes at air shows that are going maybe 3/4 that speed. You'd need a decent camera - with a some good zoom and fast shutter speed. It's just you don't often get the chance to see such a thing going above mach one at low altitude. The sonic boom from a plane that big, if it was really low (500 feet) would probably knock you over and maybe blow-out your eardrums. The only sonic boom I've ever heard was 50 miles off New York, so it was probably a Concorde at 40,000 feet, but it still sounded like nearby fireworks.

 

[ranger]

At first I thought we needed a special camera or something to do this. Thanks for clearing it up.

 

[FredGarvin]

Here's the video that has been mentioned. It really is fantastic to see this actually happening.

http://www.soargbsc.com/SoundBarrier.mpeg

Also check this one out. You don't get the vapor formation, but take a close look at the water under the aircraft...

http://mikehowells.com/superflyby.mpg

This is also what Clausius was referring to in his other thread:
http://www.fluidmech.net/tutorials/sonic/prandtl-glauert-clouds.htm