The mysterious cough, caught on film – International Herald Tribune
At Pennsylvania State University, a professor of engineering has captured something less whimsical but no less ephemeral — a cough — on film.

The image, published online Oct. 9 by The New England Journal of Medicine, was created by schlieren photography, which “takes an invisible phenomenon and turns it into a visible picture,” said the engineering professor, Dr. Gary Settles, who is the director of the university’s gas dynamics laboratory.