Second look finds no comet reservoir.Planetary scientists proposed more than 4 decades ago that a vast storehouse of comets exists at the fringes of the solar system. This reservoir, the Kuiper belt, would replenish the supply of short-period comets, many of which shatter or suffer a fatal collision during frequent visits to the inner solar system. Last year, astronomers using the Hubble Space Telescope Hubble Space Telescope (HST), the first large optical orbiting observatory. Built from 1978 to 1990 at a cost of $1.5 billion, the HST (named for astronomer E. P. Hubble) was expected to provide the clearest view yet obtained of the universe. reported detecting about 30 comet-sized objects apparently belonging to the Kuiper belt. Previous studies with ground-based telescopes had found objects in the proposed belt that were about 10 times too big to qualify as comets. Although the Hubble find made front-page headlines, Anita L. Cochran of the University of Texas at Austin “University of Texas” redirects here. For other system schools, see University of Texas System. The University of Texas at Austin (often referred to as The University of Texas, UT Austin, UT, or Texas and her collaborators emphasized that they had relied on statistical methods to determine that some of the faint, barely detectable blobs in the Hubble images were in the Kuiper belt (SN: 5/13/95, p. 293). In February, the researchers used Hubble to reexamine re·ex·am·ine also re-ex·am·ine tr.v. re·ex·am·ined, re·ex·am·in·ing, re·ex·am·ines 1. To examine again or anew; review. 2. Law To question (a witness) again after cross-examination. the same patch of sky. This time, Cochran says, analysis of the images failed to reveal any distant comets. For unknown reasons, there was more electronic noise in the pictures than before, which might explain why her team came up empty-handed. Cochran presented the findings on June 8, during a workshop on the Kuiper belt at the University of Toronto's Canadian Institute for Theoretical Astrophysics Makeup CITA has a small number of long-term faculty members, and a larger number of short term (3- or 5-year) postdoctoral positions, as well as an active visitor program; the purpose of the relatively high influx of new researchers or visitors is to ensure that timely topics . The failure to replicate the earlier results "makes the [Kuiper] finding shakier," says comet expert Brian G. Marsden Brian G. Marsden (born August 5,1937) is a British astronomer, the longtime director of the Minor Planet Center(MPC). He specializes in celestial mechanics and astrometry, collecting data on the positions of asteroids and comets and computing their orbits, often from minimal of the Smithsonian Astrophysical Observatory The Smithsonian Astrophysical Observatory (SAO) is a "research institute" of the Smithsonian Institution headquartered in Cambridge, Massachusetts, where it is joined with the Harvard College Observatory (HCO) to form the Harvard-Smithsonian Center for Astrophysics (CfA). in Cambridge, Mass. Late this summer, Cochran's team will have 24 hours of additional Hubble time, more than double the amount previously allotted. "[E]ither the results will be convincing . . . or we will have found the error in our ways," says Cochran. |
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