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Special Topic: Past Spacecraft Missions

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Special Topic: The Tunguska Event and Other Recent Impacts

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Special Topic: Orbits and Future Returns

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Special Topic: Lunar and Planetary Impacts

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During the third week of July 1994 the various fragments of Comet Shoemaker-Levy 9 1993e impacted Jupiter, liberating enormous amounts of energy in the process and creating large planet-sized “scars” in Jupiter’s atmosphere that lingered for some time afterwards. (Comet Shoemaker-Levy 9 and these events are discussed in a future “Comet of the Week” presentation.) …

A significant part of our knowledge about the “small bodies” of our solar system has come from the various spacecraft missions that have been to – or at least by – some of them. I’ll be covering these missions as a whole in a future “Special Topics” presentation, and where appropriate I am including results from …

To our ancestors of several centuries to a few millennia ago, the nighttime sky was, to some extent anyway, a generally predictable place. The stars remained “fixed” relative to each other in the patterns that we call constellations, each culture “seeing” whatever constellations that they considered relevant. While these shifted east-to-west over the course of …

The “visible” light that our eyes see, and that most of our telescopes detect, is only a very small part of the electromagnetic spectrum. The full EM spectrum encompasses everything from the long-wavelength, low-frequency, low-energy radio waves, on down through infrared, then “visible” or optical light, and then into the shorter-wavelength, higher-frequency, and higher-energy ultraviolet, …

NASA spacecraft arrival at Pysche asteroid artwork

When it comes to their composition and internal structure, there is a wide variety among the asteroids. We know this primarily through two means: the study of the various meteorites that have landed on Earth – the subject of a future “Special Topics” presentation – and examination of their spectrum. Although asteroids do not give …

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 …