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exobiology

(Encyclopedia)exobiology or astrobiology, search for extraterrestrial life within the solar system and throughout the universe. Philosophical speculation that there might be other worlds similar to ours dates back ...

lupus

(Encyclopedia)lupus lo͞oˈpəs [key], noninfectious chronic disease in which antibodies in an individual's immune system attack the body's own substances. In lupus, known medically as lupus erythematosus, antibodi...

Chandrasekhar, Subrahmanyan

(Encyclopedia)Chandrasekhar, Subrahmanyan so͝obˌrəmänˈyən chŭnˌdrəsāˈkər [key], 1910–95, American astrophysicist, b. Lahore, India (now Pakistan). He became a professor at the Univ. of Chicago in 1938...

burn

(Encyclopedia)burn, injury resulting from exposure to heat, electricity, radiation, or caustic chemicals. Three degrees of burn are commonly recognized. In first-degree burns the outer layer of skin, called epiderm...

blowfly

(Encyclopedia)blowfly, name for flies of the family Calliphoridae. Blowflies are about the same size as, and resemble, the housefly; because they are usually metallic blue or green they are also called bluebottle o...

liquid crystal

(Encyclopedia)liquid crystal, liquid whose component particles, atoms or molecules, tend to arrange themselves with a degree of order far exceeding that found in ordinary liquids and approaching that of solid cryst...

Local Group

(Encyclopedia)Local Group, in astronomy, loose cluster of at least 40 nearby galaxies, including our own Milky Way galaxy, the Andromeda Galaxy, and the Magellanic Clouds. The Local Group is spread over an ellipsoi...

McCarthy, Gina

(Encyclopedia) McCarthy, Gina (Regina McCarthy), 1954- , American environmentalist and government official, Brighton, Ma., Univ. of Ma., Boston (B.A., 1976), Tufts U...

Sagan, Carl Edward

(Encyclopedia)Sagan, Carl Edward sāˈgən [key], 1934–96, American astronomer and popularizer of science, b. New York City. Early in his career he investigated radio emissions from Venus and concluded that the c...

crossing over

(Encyclopedia)crossing over, process in genetics by which the two chromosomes of a homologous pair exchange equal segments with each other. Crossing over occurs in the first division of meiosis. At that stage each ...