- The Axiom of Choice (AC) was formulated about a century ago, and it was controversial for a few of decades after that; it might be considered the last great controversy of mathematics. It is now a basic assumption used in many parts of mathematics.
- Scorpius (Wikipedia)
Scorpius is a zodiac constellation located in the Southern celestial hemisphere, where it sits near the center of the Milky Way, between Libra to the west and Sagittarius to the east. Scorpius is an ancient constellation that pre-dates the Greeks; it is one of the 48 constellations identified by the Greek astronomer Ptolemy in the second century. Its old astronomical symbol is ♏︎.