VISIBLE sonic boom

I saw this image lately, and I read that it wasn't actually a sonic boom. It *was* something created by the sheer speed of the plane, but not actually a sonic boom. I'll try and find more information and edit it into this post when I do. Anyone else is encouraged to respond with more...

Clarification: No doubt that a sonic boom will be occuring in this picture, but the cloud is *not* a sonic boom.

and just FYI, sonic booms are *loud*. They sound like big explosions. I've heard a few - my proximity to DC means I heard some last Tuesday (apparently that's how the carbomb theory started too - fighter jets were taking off and making sonic booms, and people thought they were carbombs), as well as one time back up in Maryland when a fighter jet (I'm guessing) went zipping by as I was working on my roof.

MORE clarification: I'm retarded today, and my brain isn't working. Every time I read this, I find something else I want to say. FYI again, a sonic boom occurs when the sound gets to your ear. It's not a thing really, it's just a phenomenon of sound. Sound == vibration, remember. I'm sure we could find more on it. And I just did. Check out

http://www.physlink.com/ae53.cfm

I love Google.