Topic

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 …

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 …

Few, if any, sights in the nighttime sky are more impressive than that of a bright, long-tailed comet. It is little wonder that our ancestors of just a few centuries ago, who had little idea of what they were actually seeing, were amazed and perhaps even terrified of the sight, and even today the appearance …

Five weeks ago I devoted the “Special Topics” presentation to the subject of the Oort Cloud, the large spherical cloud of comets that is believed to enshroud the solar system out to distances of several tens of thousands of Astronomical Units. The comets in the Oort Cloud have been there since the forming Jupiter and …

In previous “Special Topics” presentations I have focused on asteroid populations in the “main asteroid belt” between Mars and Jupiter, and on asteroids in near-Earth space. If, however, as is now widely believed to be the case, asteroids are among the “leftovers” of the planet formation process, we would accordingly expect asteroids to exist in …

All astronomers, be they professional or amateur, or even just casual sky-watchers, have often had to contend with the vagaries of the earth’s atmosphere. Clouds will often get in the way, especially at inopportune times; almost every astronomer can recite stories of important observations that were precluded by cloudy weather. Even if the skies are …