The USA's National Aeronautics and Space Administration has turned to a process devised in 1864 to help its scientists measure shock waves created by supersonic aircraft flight. The method, called schlieren photography, was invented by German scientist August Toepler to observe the effect of objects moving through transparent media, such as water or air. Toepler used a light source with almost parallel rays to pass through the media as the object travelled, and used the change in refractive index of the media directly in front of the object to determine the strength of the shock wave.

NASA has, of course, developed the process a little since, and went through stages of measuring the disruption of backgrounds made up of regular patterns. Using the desert as a backdrop, the administration flew NASA F18 aircraft at up to 768mph beneath a NASA Beechcraft B200 King Air fitted with cameras that could shoot at 109 frames per second.

The project aims to study how shock waves are formed 
and to develop aircraft designed to reduce the impact of supersonic flight, 
so that commercial planes can eventually travel at much higher speeds.

The next stage involved using a T-38 supersonic jet and cameras with even higher frame rates and resolution. The images recorded were put through NASA-developed software to remove the desert background so that rough shock wave patterns could be seen. The images were then combined and averaged, to build the clearer impression of the waves as seen the pictures here.

The project aims to study how shock waves are formed and to develop aircraft designed to reduce the impact of supersonic flight, so that commercial planes can eventually travel at much higher speeds. In the meantime, we can admire the very cool patterns the shock waves make in the NASA images.

For more information visit the 'Shock and Awesome' page of the NASA website.