Word: center
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Dates: during 1970-1979
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...form helium marks the beginning of a long and stable period in the evolution of the star−a combination of adolescence and middle age that constitutes 99% of the lifespan of a sun-size star. During this period, the tremendous energy radiating from the star's center neutralizes its gravitational force, and the great glowing orb shrinks no further. But as it must to all stars, death eventually comes. How long a star lives depends on its mass. Generally, the more massive a star is, the shorter its life is. Stars with a mass significantly greater than that...
...direct observation, but it can be inferred. Astronomers have identified a powerful X-ray source in the constellation Cygnus. Some suspect the source, which has been labeled Cygnus Xl, may be just such a black hole. It appears to be rotating with a visible star around a common center of gravity−a dead partner of a dualstar system. Scientists believe material from the glowing star is being drawn into the black hole with such force that the material becomes hot enough to emit X rays...
...happening as a Christmas ballet. At the Bolshoi in Moscow, there are no children's matinees and no children among the dancers. Still, tickets were impossible to come by last week. In the U.S., each year seems to bring a new production somewhere. This week at the Kennedy Center in Washington, D.C., the American Ballet Theater begins a two-week run with a new Nutcracker choreographed by and starring Mikhail Baryshnikov. In New York City, alas, Balanchine's 22-year-old production, the best and most popular of all contemporary versions, was stopped by a musicians' strike...
...very satisfied with it. Besides, the big thing is confidence. You do better with a racquet you have confidence in." Last week, after trying a friend's new Pancho Segura "SweetSpot"−notable for its wider spacing between strings near the rim than at the center. Manhattan Housewife Flip Breckenfeld offered to buy it on the spot. Said she: "I've never hit the ball so well...
After Siegel had spent only a single night at the new sleep-wake clinic of New York's Montefiore Hospital and Medical Center, Neurologist Elliot Weitzman's suspicions about him were confirmed; as soon as Siegel fell asleep, the functioning of the muscles of his upper respiratory tract became so impaired that breathing would come to a total halt for as long as a minute (doctors are uncertain whether excessive muscle relaxation or contraction is responsible). Then Siegel would awake with a start, and in his groggy state would gasp for air with a loud snore. The loud...