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Carlsbad Caverns National Park

(Encyclopedia)Carlsbad Caverns National Park, 46,766 acres (18,940 hectares), SE N.Mex., in the Guadalupe Mts.; designated a national park in 1930. These connecting limestone caves, with remarkable stalactite and s...

Neptune, in astronomy

(Encyclopedia)Neptune, in astronomy, 8th planet from the sun at a mean distance of about 2.8 billion mi (4.5 billion km) with an orbit lying between those of Uranus and the dwarf planet Pluto; its period of revolut...

distillation

(Encyclopedia)distillation, process used to separate the substances composing a mixture. It involves a change of state, as of liquid to gas, and subsequent condensation. The process was probably first used in the p...

ultraviolet astronomy

(Encyclopedia)ultraviolet astronomy, study of celestial objects by means of the ultraviolet radiation they emit, in the wavelength range from about 90 to about 350 nanometers. Ultraviolet (UV) line spectrum measure...

radio-frequency identification

(Encyclopedia)radio-frequency identification (RFID), a technology that uses radio waves to transmit data and uniquely identify an animal, person, or thing. An RFID system typically consists of a tag and a reader. T...

carbon dioxide

(Encyclopedia)carbon dioxide, chemical compound, CO2, a colorless, odorless, tasteless gas that is about one and one-half times as dense as air under ordinary conditions of temperature and pressure. It does not bur...

atmosphere

(Encyclopedia)CE5 Atmosphere atmosphere [Gr.,=sphere of air], the mixture of gases surrounding a celestial body with sufficient gravity to maintain it. Although some details about the atmospheres of other plane...

noise

(Encyclopedia)noise, any signal that does not convey useful information. Electrical noise consists of electrical currents or voltages that interfere with the operation of electronic systems. Electrical noise limits...

mountain beaver

(Encyclopedia)mountain beaver, stout, short-limbed North American rodent, Aplodontia rufa, not closely related to the true beaver. Also called sewellel beaver after the Chinook word for a robe made from its pelts, ...

ice cream

(Encyclopedia)ice cream, sweet frozen dessert, made from milk fat and solids, sugar, flavoring, a stabilizer (usually gelatin), and sometimes eggs, fruits, or nuts. The mix is churned at freezing temperature to att...