- Bell’s theorem is a term encompassing a number of closely related results in physics, all of which determine that quantum mechanics is incompatible with local hidden-variable theories, given some basic assumptions about the nature of measurement. “Local” here refers to the principle of locality, the idea that a particle can only be influenced by its immediate surroundings, and that interactions mediated by physical fields cannot propagate faster than the speed of light. “Hidden variables” are supposed properties of quantum particles that are not included in quantum theory but nevertheless affect the outcome of experiments. In the words of physicist John Stewart Bell, for whom this family of results is named, “If [a hidden-variable theory] is local it will not agree with quantum mechanics, and if it agrees with quantum mechanics it will not be local.”
- Star Tales - Caelum (ianridpath.com)
This small and insignificant constellation in the southern hemisphere, representing an engraver’s chisel, is one of the inventions of the 18th-century French astronomer Nicolas Louis de Lacaille. He introduced it on his map of the southern stars published in 1756, where he gave it the French name les Burins (although in the accompanying star catalogue it was listed as Burin, singular). On the second edition of the map in 1763 this was Latinized to Caelum Scalptorium. In 1844 the English astronomer John Herschel proposed shortening the name to Caelum. Francis Baily adopted this suggestion in his British Association Catalogue of 1845, and it has been known as Caelum ever since.
- John Stewart Bell (Wikipedia)
John Stewart Bell FRS (28 July 1928 – 1 October 1990) was a physicist from Northern Ireland and the originator of Bell’s theorem, an important theorem in quantum physics regarding hidden-variable theories.