[en] The article reviews some aspects of short timescale phenomena in astronomy. The Long Period Variables and the Cepheid Variables are examples of pulsating stars and illustrates the application of the gravitational timescale. ZZ Ceti is an example of pulsating white dwarfs. Conservation of angular momentum results in the material forming a gaseous disc around the white dwarf through which material steadily accumulates on the surface of the white dwarf. This structure underlies the novae and dwarf novae. Stellar rotation is also discussed