Posts in category

Ice and Stone


Comet of the Week: Ikeya-Seki 1965f

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Special Topic: Kreutz Sungrazers

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Comet of the Week: Siding Spring C/2013 A1

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Special Topic: 1I/‘Oumuamua

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Perihelion: 1986 February 9.46, q = 0.587 AU  Those of us space-minded people who came of age during the middle decades of the 20th Century learned of Comet Halley and its impending return in 1986, and many of us undoubtedly heard stories of its appearance during its excellent return in 1910; my paternal grandmother, an …

To our ancestors of just a few centuries ago, comets were, at best, mysterious objects, very possibly of divine or supernatural origin. When one considers that bright comets could appear anywhere in the nighttime sky, seemingly out of nowhere, and after being visible for a few days or weeks would then disappear, it is little …

MARCH 1, 1705: British astronomer Edmond Halley publishes his calculations of the orbits of the comets of 1531, 1607, and 1682, concluding that they are individual returns of the same comet, and that that comet would return in 1758. His prediction turned out to be correct, and the comet has been named in his honor. …

Perihelion: 1976 February 25.22, q = 0.197 AU  What I consider to be the best comet I have ever seen was missed by most of the general public. Part of this was due to the fact that it put on its best appearance in the sleepy hours before dawn, but a large part of it …

Once it had become clear that comets are bona fide members of the solar system just as planets and asteroids are, the question then becomes just what their physical nature might be. While they may appear to be fairly large in our nighttime sky, the fact that background stars shine through their tails and their …

When the Giotti spacecraft launched on its voyage to explore Halley’s Comet in 1985, it was an invention by the son of an Iowa farmer decades earlier that allowed the mission to be successful.  The most difficult problem of the mission to overcome was how to ensure that Giotto survived long enough to snap its …