Word: parallaxes
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Dates: during 1930-1939
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...distance from the sun is 4.3 light years -about 25 trillion miles. In 1915 Dr. Robert T. A. Innes of Johannesburg discovered, by parallax observations,* that a faint star near Alpha Centauri was only 4.16 light-years away. For 23 years, up to last week, that star, appropriately called Proxima Centauri, held rank as the No. 1 solar neighbor. Last week, from the University of Chicago's Yerkes Observatory in Wisconsin, it was announced that another faint star, Wolf 424† appears to be only 3.7 light-years distant. This is so close that a train traveling a thousand...
Director Otto Struve of Yerkes would not say for sure that Wolf 424 is the sun's nearest known neighbor. It may be a double star, in which case the combined light of the two components would make it appear closer than it actually is. Parallax measurements requiring a year or more will be necessary to settle the contest between Proxima Centauri and Wolf...
...Parallax is the apparent motion of a star caused by the earth's revolution around the sun. The nearer the star, the larger the apparent motion...
...Agriculture in connection with soil conservation work. In a vertical aerial photograph the earth's surface looks perfectly flat. Third dimensional relief can be obtained by the principle employed in the oldtime stereoscope. Pictures of the same area are shot from two slightly different positions, thus providing a parallax in the same way that a person's two eyes do in normal sight. The two pictures are then inserted in a super-glorified stereoscope (built with Zeiss for $50,000). So accurate are the controls, so precise the instruments, that with the aid of another optical illusion...
...Presiding over the congress was a U. S. astronomer, square, heavy-jowled Director Frank Schlesinger of Yale Observatory, whose fame is associated with parallax. Earth's annual orbit around the Sun is 186,000,000 miles across; therefore the direction of stars as observed from Earth on opposite sides of that orbit changes slightly. This change is called parallax. Even the nearer stars are so far off that their parallax is extremely small, and for remote stars it is not discernible at all. Nevertheless since the amount of apparent displacement depends on how far away the star is, parallax...