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Ice and Stone


Comet of the Week: Bennett 1969i

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Special Topic: Ancient Ideas about Comets

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Comet of the Week: Comet Hyakutake C/1996 B2

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Special Topic: “Small Bodies” and the Electromagnetic Spectrum

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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, …

lunar meteorite close-up image

MARCH 15, 2020: Comet ATLAS C/2019 Y1 will pass through perihelion at a heliocentric distance of 0.838 AU. This is the fourth known member of a “group” of comets, the first of which appeared in 1988; this, and other comet “groups,” are discussed in a future “Special Topics” presentation. Comet ATLAS has become bright enough …

The Great Comet of 1843’s Perihelion: 1843 February 27.91, q = 0.006 AU  For the first time in “Ice and Stone 2020,” a Kreutz sungrazer is my “Comet of the Week.” Some of the members of this group of comets have been among the brightest and most spectacular comets in all of recorded history, and as …

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 …

MARCH 8, 1772: A French amateur astronomer, Jacques Montaigne, discovers a comet that is followed for one month and that reaches 7th magnitude. Over the next 5½ decades the comet is discovered on two subsequent returns, the latter of these being in 1826 by an Austrian army officer, Wilhelm von Biela, for whom it was …

Comet 1P/Halley 1982i’s 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 …