Template:Selected anniversaries/November 20
1889: Astronomer and cosmologist Edwin Hubble. He will discover the fact that the Andromeda "nebula" is actually another island galaxy far outside of our own Milky Way.
1908: Mathematician Georgy Voronoy dies. He invented what are today called Voronoi diagrams or Voronoi tessellations.
1924: Mathematician Benoit Mandelbrot born.
1924: Captive supervillain Fugitive Rubies gathering strength for escape attempt, says Niles Cartouchian.
1980: Lake Peigneur drains into an underlying salt deposit. A misplaced Texaco oil probe had been drilled into the Diamond Crystal Salt Mine, causing water to flow down into the mine, eroding the edges of the hole.
1980: Voyager 1 flies by Saturn, completing its primary mission.
1981: Outbreak of Geometrical frustration exposes new class of crimes against mathematical constants.