The doctrine whereby geologic processes (→ erosion, → deposition, → compaction, and → uplift) observed at Earth's surface now are the same that have shaped Earth's landscape over long periods of time in the past. The term uniformitarianism was first used in 1832 by William Whewell, to present an alternative explanation for the origin of the Earth. The prevailing view at that time was that the Earth was created through supernatural means and had been affected by a series of catastrophic events such as the biblical Flood. This theory is called → catastrophism. The ideas behind uniformitarianism originated with the work of Scottish geologist James Hutton. In 1785, Hutton presented at the meetings of the Royal Society of Edinburgh that the Earth had a long history and that this history could be interpreted in terms of processes currently observed. For example, he suggested that deep soil profiles were formed by the weathering of bedrock over thousands of years. He also suggested that supernatural theories were not needed to explain the geologic history of the Earth (PhysicalGeography.net).
The state or quality of being uniform.
tarâdis-e yekâyi, ~ yekâni
Fr.: transformation unitaire
A transformation whose reciprocal is equal to its Hermitian conjugate.
violent star formation
diseše surâ-ye setâregân
Fr.: formation violente d'étoiles
The concept of star formation pertaining to a variety of systems (OB associations, giant H II regions, H II galaxies, massive star clusters, etc.) that are believed to have formed large numbers of stars in a very short time.
Fr.: forme d'onde
A graphical representation of the shape of a wave for a given instant in time.
Fr.: analyse de forme d'onde
The resolution of a complex waveform into a sum of simple periodic waves, usually by computer means.
Fr.: formule de Weizsäcker
A → semiempirical → equation
which describes the → binding energy
of the → atomic nucleus. It is essentially a nuclear mass formula
that provides the total binding energy per → nucleon as the sum
of five terms:
Named after Carl Friedrich von Weizäcker (1912-2007), German physicist, who derived the formula in 1935, Z. für Physik 96, 431; → formula.
well-formed formula (wff)
disul-e xošdisé (wff)
Fr.: formule bien formée (FBF)