Two Big US Navy Fighter Jets

U.S. Navy photo by Jimmy C. Pan

These are F/A-18 Hornet fighter jets. This picture was taken when they were flying past an aircraft carrier (like this one) and at very high speed. Can you imagine how loud that was? All that steam you see at the back of each plane is happening because they are traveling through the air faster than sound travels. That means they are "breaking" the "Sound Barrier." When that happens, the jet makes a very loud sound, sometimes called a sonic boom.

You can read more about the sound barrier by visiting this website:

http://www.livescience.com/mysteries/070323_mach_speed.html