Refraction
Refraction was the change of a lightwave into a direction opposite the intended direction.

Terraformer Kurt Mandl mentioned that refraction and a thin atmosphere on Velara III was interesting but no indication of life. ()

Among the artifacts Vash brought back from the Gamma Quadrant in 2369 was an object that appeared to be some kind of Promethean quartz, however, its molecular density and refraction index was much higher. ()

See also 
 Refraction pulse

External link 
 
Physics