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Ice and Stone


Comet of the Week: 67P/Churyomov-Gerasimenko

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Special Topic: Life in Martian Meteorites?

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Comet of the Week: NEOWISE C/2020 F3

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Special Topic: Terrestrial Impact Craters

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JULY 5, 1687: British physicist Isaac Newton publishes his Philosophiae Naturalis Principia Mathematica (Mathematical Principles of Natural Philosophy), usually known as the Principia, wherein he lays out what is now known as his Law of Universal Gravitation. Part of Newton’s work in the Principia was based upon his calculations of the Great Comet of 1680 …

Perihelion: 2005 July 05.31, q = 1.506 AU  With the various comprehensive survey programs that are currently operational, the discovery of previously-unknown short-period comets happens all the time these days. The situation was very different during the mid-19th Century, when only a handful of such objects were known, and the discovery of each one was …

The majority of what we know about the various planets and many of the other objects in our solar system has come from spacecraft missions sent to those bodies. Even with the best telescopes here on Earth many of these objects are little more than points of light in the sky, and it was only …

JUNE 28, 1911: A meteorite falls to the ground near the village of El Nakhla El Bahariya, Egypt. The Nakhla meteorite was one of the first-known meteorites determined to have come from Mars. A fragment of the Nakhla meteorite supposedly struck and killed a dog, although there has been no independent confirmation of this. “Martian …

Perihelion: 1861 June 12.01, q = 0.822 AU  Two of the brighter comets of the latter half of the 19th Century were discovered by an Australian amateur astronomer, John Tebbutt, who for four decades essentially ran a one-man astronomical clearinghouse from his private observatory near Windsor, New South Wales. In addition to numerous astrometric observations …

During the early morning hours on Tuesday, June 30, 1908, at around 7:17 A.M. local time, “something” entered the earth’s atmosphere near the Pacific coast of Asia, traveling northwestward. A few km above the surface of a largely uninhabited region of central Siberia, near the Stony Tunguska River some 90 km north-northwest of the village …