principal diameter
51Star — For other uses, see Star (disambiguation) …
52Opportunity rover — (MER B) Opportunity in April 2003 Operator NASA Mission type Rover …
53eclipse — eclipser, n. /i klips /, n., v., eclipsed, eclipsing. n. 1. Astron. a. the obscuration of the light of the moon by the intervention of the earth between it and the sun (lunar eclipse) or the obscuration of the light of the sun by the intervention …
54lipid — /lip id, luy pid/, n. Biochem. any of a group of organic compounds that are greasy to the touch, insoluble in water, and soluble in alcohol and ether: lipids comprise the fats and other esters with analogous properties and constitute, with… …
55explosive — explosively, adv. explosiveness, n. /ik sploh siv/, adj. 1. tending or serving to explode: an explosive temper; Nitroglycerin is an explosive substance. 2. pertaining to or of the nature of an explosion: explosive violence. 3. likely to lead to… …
56lighthouse — /luyt hows /, n., pl. lighthouses / how ziz/. 1. a tower or other structure displaying or flashing a very bright light for the guidance of ships in avoiding dangerous areas, in following certain routes, etc. 2. either of two cylindrical metal… …
57materials science — the study of the characteristics and uses of various materials, as glass, plastics, and metals. [1960 65] * * * Study of the properties of solid materials and how those properties are determined by the material s composition and structure, both… …
58spectroscopy — spectroscopist /spek tros keuh pist/, n. /spek tros keuh pee, spek treuh skoh pee/, n. the science that deals with the use of the spectroscope and with spectrum analysis. [1865 70; SPECTRO + SCOPY] * * * Branch of analysis devoted to identifying… …
59Anthropology and Archaeology — ▪ 2009 Introduction Anthropology Among the key developments in 2008 in the field of physical anthropology was the discovery by a large interdisciplinary team of Spanish and American scientists in northern Spain of a partial mandible (lower… …
60Minor planet moon — 243 Ida and its moon Dactyl as imaged by the Galileo spacecraft in 1993 …
