Here are the week’s Twitter #weirdscifacts!

543. Sep 07: The “massacre of Monkey Hill“.  In this insightful post by @ericmjohnson on the evolutionary origins of collective violence, the massacre is described.  In 1930, a newly-installed colony of 140 baboons had been installed in the London Zoo.  A single incident amongst the primates sparked a cycle of violence that eventually left two thirds dead.

544. Sep 08: Geologist William Buckland (1784-1856) would wear his academic gown to do field work.  We’re talking about wearing an academic gown to do geological work out in the field — climbing, digging, and hiking in all sorts of adverse weather!

545. Sep 09: Man gets $75k for completing proof of “enormous theorem”, which runs 15,000 pages.  I had read about this theorem years ago, but couldn’t remember the details for #weirdscifacts!  Tip o’ the hat to @edyong209 for reminding me.

546. Sep 10: Jupiter’s “Great Red Spot“: a storm that could fit 2-3 Earths within it that has been going 300 years! Most everyone knows about the “Great Red Spot”, but many may not have grasped its significance — it is essentially a massive hurricane that is larger than the Earth and has been going since before the founding of the U.S.!

547. Sep 11: September 11, 1881: The landslide of Elm.  Before the World Trade Center attacks, September 11th was known for another man-made tragedy, an unusual landslide triggered by human activity.  (via @rmathematicus and @david_bressan)

548. Sep 12: Modern glacier theory was introduced to skeptical scientists by hunter Jean-Pierre Perraudin in 1821. Science can have its occasional blind sides!  Geologists of the early 1800s were still working under the theory that the massive boulders found around the landscape in parts of Europe were remains of the biblical flood.  Perraudin, a hunter in the region, noted that the rocks were often obviously associated with scratches in the land that led right to glaciers.  In 1815, he suggested to scientist Jean de Charpentier that the rocks had been placed by receding glaciers, but Charpentier dismissed him. In 1821, however, an engineer Ignace Venetz visited the region, and was convinced by Perraudin’s speculations.  Ironically, Venetz eventually convinced Charpentier of the validity of the hunter’s novel theory.

549. Sep 13: Arabic numerals were initially banned in some parts of Europe, due to fears of manipulation & fraud.  The numerals were originally developed in India and made their way to the Middle East, where they became heavily used in commerce; from there they made their way to Europe. The simplicity of the numerals, however, led to fears that they could be changed easily in documents.  They were banned for a time in Northern Italy before presumably their usefulness overrode the fears.  (h/t @rmathematicus)