Making your own cloud:

 If you have a jet fighter and a few minutes to spare, why not make your own cloud? All you have to do is fly the plane at high speed through fairly moist air. As it flies, the plane creates shock waves, which alternately squeeze up the air (making it higher pressure) and stretch it out (making it lower pressure). When you lower the pressure of moist air, you get a cloud - and that's what creates the amazing *condensation clouds* you see in photos like this. It gives a whole new meaning to that old song lyric: "Everywhere you go, you always take the weather with you." [U.S. Navy photo by Ensign John Gay.]