Cold cloud may contain unseen solar dust.Cold cloud may contain unseen solar dust New astronomical findings show far less dust surrounding the sun than around similar stars, leading to speculation that the sun's "missing" dust actually lies in an unseen cloud encircling the solar system. At the Jet Propulsion Laboratory “JPL” redirects here. For other uses, see JPL (disambiguation). Jet Propulsion Laboratory (JPL) is a NASA research center located in the cities of Pasadena and La Cañada Flintridge, near Los Angeles, California, USA. in Pasadena, Calif., H.H. Aumann studied 36 of the nearest stars resembling the sun in color and temperature. As reported in the October ASTRONOMICAL JOURNAL, he found they typically emit 500 times more far-infrared radiation than our star apparently does. Aumann used data from the international Infrared Astronomy Satellite (IRAS IRAS: see infrared astronomy. ), the only orbiting spacecraft that has recorded far-infrared emissions from space. Invisible energy that travels in waves less than a millimeter apart, far-infrared radiation usually arises from star-heated dust. Sun-warmed dust beyond the outer planets theoretically could produce the "missing" energy, says T.N. Gautier of California Institute of Technology California Institute of Technology, at Pasadena, Calif.; originally for men, became coeducational in 1970; founded 1891 as Throop Polytechnic Institute; called Throop College of Technology, 1913–20. in Pasadena. That dust might exist within a cloud of comet nuclei that Dutch astronomer Jan H. Oort in 1950 predicted circles the sun at a distance at least 750 times farther than Pluto. Aumann says IRAS data might manifest Oort clouds around the sun's stellar peers without necessarily revealing one around the sun, because distant sources emit highly focused radiation, while a closer cloud would yield a diffuse signal. Warmer dust in the solar system also obscures emissions from colder particles beyond the outer planets. Using the IRAS data, Aumann now is "trying to isolate the signal from the hotter stuff in the foreground so we can separate it out to see colder dust beyond." Astronomers plan to intensify the search with powerful new satellite-based infrared telescopes, the first of which -- NASA's Cosmic Background Explorer Cosmic Background Explorer: see infrared astronomy. Cosmic Background Explorer (COBE) U.S. satellite that from 1989 to 1993 mapped the cosmic background radiation field. In 1964, microwave radiation was discovered that permeated the cosmos uniformly. (COBE COBE: see infrared astronomy. )--is scheduled for launch in May 1989. "If a dust cloud is out there," says Michael G. Hauser of NASA's Goddard Space Flight Center The Goddard Space Flight Center (GSFC) is a major NASA space research laboratory established on May 1, 1959 as NASA's first space flight center. GSFC employs approximately 10,000 civil servants and contractors, and is located approximately 6.5 miles northeast of Washington, D.C. in Greenbelt, Md., "COBE will see it." However, distinguishing it from other far-infrared sources may prove difficult because of COBE's extreme sensitivity. The European Space Agency European Space Agency (ESA), multinational agency dedicated to the promotion, for exclusively peaceful purposes, of cooperation among European states in space research and technology. plans to launch an infrared-observation satellite by the mid-1990s, and NASA hopes to put another into orbit by 2000. But disproof dis·proof n. 1. The act of refuting or disproving. 2. Evidence that refutes or disproves. Noun 1. disproof - any evidence that helps to establish the falsity of something of the dust cloud's existence could emerge earlier, Gautier says, if "theoretical consequences of such an abundance of material are shown to conflict with other observations." |
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