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Ultraviolet radiation | electromagnetic radiation of wavelengths shorter than the shortest (violet) wavelengths to which the eye is sensitive; radiation of wavelengths in the approximate range of 10 to 400 nm |
UNESCO | United Nations Educational, Scientific, and Cultural Organization; founded 1946. Brought into relationship with the United Nations in 1946. UNESCO seeks to broaden the base of education throughout the world, to bring the benefits of science to all countries, and to encourage cultural interchange. |
Uniformitarianism | slow gradual processes with infrequent catastrophic events restricted to a local scale; the doctrine that ancient, geologic changes occurred largely in response to slow and gradual processes, without significant periods of rapid and catastrophic change |
Universal rock units* | units of rock layers that are global in extent |
Universe | the totality of all things that exist; creation; cosmos |
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Vadose theory | a theory for the formation of limestone caves that suggests that solution of the cavity occurred while the limestone was above the level of groundwater (water table) and that the cavity was largely filled with air |
Vadose water | CO2 rich, oxygen rich, organic poor and low salinity |
Vertical changes | accumulation of changes that leads to the evolution of a new kind; macroevolution |
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Waw-consecutive | a Hebrew language construction to express consecutive action |
Worldview | a philosophy of life. A worldview is a set of interrelated basic beliefs. |
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Xenocrysts | a crystal in an igneous rock which has not crystallized from the melt but has been introduced into the melt from an external source |
Xenoliths | a rock fragment embedded in the mass of another rock |
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Z number | the number of protons in each atom of a particular element. Also called the Atomic number. |
Zooplankton | the microscopic animal life found floating or drifting in the ocean or in bodies of fresh water, used as food for fish |
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