Abstract
AN exhaustive discussion of the phenomena of Halley's comet and its envelopes, based on the examination of a large number of photographs taken at the Lick Observatory, at its Chile station, and at Mount Wilson, Johannesburg, Helwan, Kodaikanal, Cordoba, Yerkes, Tokyo, and Beirut, is given by Nicholas T. Bobrovnikoff in a memoir on “Halley's Comet in its Apparition of 1909–1911”; which appears in Lick Observatory Publications, Part 2. The outward motion of luminous patches in the tail was studied, and the repulsive force deduced, the assumption being made that the hyperbolic orbits of these objects were in the same plane as the orbit of the comet?s nucleus. The resultant repulsive force was calculated in 31 cases; in 3 cases it exceeded 1,000 times gravity; in 4 cases it was between 100 and 1,000 times; in 6 cases it was between 50 and 100 times. The two tails of the comet on May 29, 1910, are traced on page 457 of the memoir. That of Bredichin?s type I is nearly straight, the indicated repulsive force ranging from 9 to 16; the tail of type II is highly curved, the repulsive force being only 0?1 to 0?2. The presence of this curved tail explained the surprising fact that a tail could be seen in the morning sky for some time after the nucleus and straight tail had become evening objects. On account of the curvature of the tail, the author is doubtful whether the earth passed through any portion of it; in any event only the outlying portions could have been traversed.
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CROMMELIN, A. Halley's Comet in 1909–11. Nature 131, 282 (1933). https://doi.org/10.1038/131282a0
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DOI: https://doi.org/10.1038/131282a0