The use of the relative movement and gravity of a planet or other celestial body to alter the path and speed of a spacecraft.

A phenomenon of visual perception caused by staring at a uniform field of colour, leading to a sensation of blindness and sometimes to hallucinations.

plural of after-effect

An effect; especially, one that is experienced only after a delay, or only in the long term.

(psychology) The phenomenon that someone is less likely to help another if other potential helpers are present than otherwise.

The secondary emission of an electron following the ionisation of a core electron of an atom.

(computing, software) The replacement, by a spell checker, of words that it interprets as being misspelled, by words which are still incorrect in context.

(physics) The polarization of the spin of electrons produced when alkali atoms absorb circularly polarized light; any of several similar quantum optical effects

A phenomenon in which attempting to suppress an item of information attracts even more unwanted attention, thus furthering its dissemination.

plural of sound effect