xkcd

Webcomic: xkcd, updates every Monday, Wednesday and Friday

Kepler's Defense of Tycho against Ursus

History of Astronomy: Kepler's Defense of Tycho against Ursus by Edward Rosen, Popular Astronomy, Vol. 54, p.405, 1946. In 1595, the inexperienced Kepler had written a flattering letter to Nicholas Reimers (who called himself Ursus (the bear)), then Imperial Mathematician to Rudolph II, Holy Roman Emperor in Prague. In 1597, Reimers issued his De astronomicis hypothesibus, with its venomous attack on Tycho Brahe. He incorporated Kepler’s letter in it without Kepler’s knowledge or consent, thereby unscrupulously making it appear that in his duel with Tycho he was supported by Kepler. Kepler himself had by now become renowned through publication of his Cosmographic Mystery. Reimers died in mid-August 1600. In October 1600, Kepler, at the request of Tycho, began composing a rebuttal of Reimers works (A Defense of Tycho against Ursus (Apologia Tychonis contra Ursum)), but it remained unpublished by the time of Tycho's death (24. October 1601). In the end, Kepler's Defense of Tycho was found among his unpublished manuscripts by Christian Frisch, who edited Kepler’s collected works, and put it in print for the first time in 1858. More on Kepler at Stanford Encyclopedia of Philosophy.

Cosmetics Directive/Regulation

Cosmetics Directive/Regulation: Provides regulatory framework for phasing out animal testing for cosmetics purposes. Bans testing of finished cosmetic products and cosmetic ingredients on animals. Prohibits to market in the EU finished cosmetic products and their ingredients which were tested on animals for cosmetics purposes. The testing ban on finished cosmetic products applies since 11 Sep 2004; the testing ban on ingredients or combination of ingredients applies since 11 Mar 2009. The marketing ban applies since 11 Mar 2009 for all human health effects with the exception of repeated-dose toxicity, reproductive toxicity and toxicokinetics. For these specific health effects the marketing ban applies since 11 Mar 2013, irrespective of the availability of alternative non-animal tests. Exemptions: Substances which are also used in other industries (e.g. pharmaceuticals) and are thus not developed for cosmetic products exclusively. Products containing animal-tested ingredients that were developed before the ban. Industry revenues (2010): 71 billion EUR ($93 billion). Ärzte gegen Tierversuche (in German).

Measuring the World: Gauß and Humboldt

Audiobook (CD): Daniel Kehlmann: Die Vermessung der Welt (2005, engl.: Measuring the World). Read in German by Ulrich Matthes. 5 CDs, ca. 345 min. Narrates and compares the biographies of two contemporaries, the natural philosopher Alexander von Humboldt and the mathematician Carl Friedrich von Gauß. "This is the history of two scientists who could not be more different, but who both have the goal to understand the world". Not comprehensive biographies, but nicely narrated with some hidden treasures. Overall rating 7 out of 10. 

Educational Animated Short Clips

Educational animated short clips by Jeremiah Warren, Dallas, TX, on Youtube: Nikola Tesla, Thomas Edison, History of the Calendar, Naming of Hurricanes, and Steve Jobs. Creative and informative.

Powers of 10 (1977)

By Charles and Ray Eames -- a classic.