In mathematics and physical science, spherical harmonics are special functions defined on the surface of a sphere. They are often employed in solving partial differential equations that commonly occur in science. The spherical harmonics are a complete set of orthogonal functions on the sphere, and thus may be used to represent functions defined on the surface of a sphere, just as circular functions (sines and cosines) are used to represent functions on a circle via Fourier series. Like the sines and cosines in Fourier series, the spherical harmonics may be organized by (spatial) angular frequency...

Nose-picking is the act of extracting nasal mucus with one's finger (rhinotillexis) and may include the succeeding action of ingesting the mucus picked from the nose (mucophagy). This action is condemned in most cultures; societies try to prevent development of the habit and attempt to break it if already established. Mucophagy is a source of mockery and entertainment in the media. However, some scientists argue that mucophagy provides benefits for the human body. Friedrich Bischinger, an Austrian doctor specializing in lungs, advocates using fingers to pick nasal mucus and then ingesting it, stating...

Misner space is an abstract mathematical spacetime, discovered by Charles Misner of the University of Maryland. It is also known as the Lorentzian orbifold R 1 , 1 / boost {\displaystyle \mathbb {R} ^{1,1}/{\text{boost}}} . An intuitive analogy may be drawn with a video game screen, where a screen element exits the frame through the right side, only to re-enter the frame right away through the left...