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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...

cellular telephone

(Encyclopedia)cellular telephone or cellular radio, telecommunications system in which a portable or mobile radio transmitter and receiver, or “cellphone,” is linked via microwave radio frequencies to base tran...

Venus, in astronomy

(Encyclopedia)Venus, in astronomy, 2d planet from the sun; it is often called the evening star or morning star and is brighter than any object in the sky except the sun and the moon. Because its orbit lies between ...

marsupial

(Encyclopedia)marsupial märso͞oˈpēəl [key], member of the order Marsupialia, or pouched mammals. With the exception of the New World opossums and an obscure S American family (Caenolestidae), marsupials are no...

prostate cancer

(Encyclopedia)prostate cancer, cancer originating in the prostate gland. Prostate cancer is one of the most common malignancies in men in the United States, second only to skin cancer, and as a cause of cancer deat...

stellar structure

(Encyclopedia)stellar structure, physical properties of a star and the processes taking place within it. Except for that of the sun, astronomers must draw their conclusions regarding stellar structure on the basis ...

body temperature

(Encyclopedia)body temperature, internal temperature of a living organism. Mammals and birds are termed warm-blooded, or homeothermic, i.e., they are able to maintain a relatively constant inner body temperature, w...

conservation laws

(Encyclopedia)conservation laws, in physics, basic laws that together determine which processes can or cannot occur in nature; each law maintains that the total value of the quantity governed by that law, e.g., mas...

European Space Agency

(Encyclopedia)European Space Agency (ESA), multinational agency dedicated to the promotion, for exclusively peaceful purposes, of cooperation among European states in space research and technology. Member states in...

photometry

(Encyclopedia)photometry fōtŏmˈətrē [key], branch of physics dealing with the measurement of the intensity of a source of light, such as an electric lamp, and with the intensity of light such a source may cast...