Voyager 2 homing in on Uranus.The planel Uranus and four of its five known moons -- but none of its at least nine rings--are shown in this photo taken from a distance of 247 million kilometers by the Voyager Voyager, airplane Voyager, the first airplane to circumnavigate the earth nonstop on a single load of fuel. Designed by Burt Rutan and flown by Dick Rutan and Jeana Yeager, Voyager took off from California on Dec. 2 spacecraft spacecraft Vehicle designed to operate, with or without a crew, in a controlled flight pattern above Earth's lower atmosphere. Since streamlining is not needed in the high vacuum of this environment, a spacecraft's shape is designed according to its mission (see , which will fly past Uranus on Jan. 24. Voyager's visit will be the first by a spacecraft to a major planet that is almost invisible to observers on earth without the aid of a telescop. The discovery of Uranus in 1781 virtually doubled the size of the known solar system solar system, the sun and the surrounding planets, natural satellites, dwarf planets, asteroids, meteoroids, and comets that are bound by its gravity. The sun is by far the most massive part of the solar system, containing almost 99.9% of the system's total mass. . The planet's rings, too narrow and dark to be visible so far to Voyager's cameras, were not detected from earth until 1977 (SN: 3/19/77, p. 180), and even then it was not because they showed up in any photograph taken through a large telescope telescope, traditionally, a system of lenses, mirrors, or both, used to gather light from a distant object and form an image of it. Traditional optical telescopes, which are the subject of this article, also are used to magnify objects on earth and in astronomy; . Their presence was inferred only because they blocked the light of a star near whose position in the sky (as seem from earth) Uranus was passing at the time. When they do become visible to Voyager, they should appear like rings on a target, because Uranus is tilted tilt 1 v. tilt·ed, tilt·ing, tilts v.tr. 1. To cause to slope, as by raising one end; incline: tilt a soup bowl; tilt a chair backward. 2. nearly pole-on to earth. Also missing from the Voyager 2 image is the planeths smallest known satellite, Miranda. At the time of the photo (July 15), the narrow-angle camera that took it could resolve features no smaller than about 4,570 km across. The image is actually a composite of two--one of Uranus itself and another, enhanced 10-fold in bridghtness, to bring out the faint satellites. |
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