In mathematics and theoretical physics, mirror symmetry is a relationship between geometric objects called Calabi–Yau manifolds (pictured). The term refers to a situation where two Calabi–Yau manifolds look very different geometrically but are nevertheless equivalent when employed as extra dimensions of string theory. Mirror symmetry was originally discovered by physicists. Mathematicians became interested in this relationship around 1990 when Philip Candelas, Xenia de la Ossa, Paul Green, and Linda Parks showed that it could be used as a tool in a branch of mathematics called enumerative geometry. Today mirror symmetry is a major research topic in pure mathematics, and mathematicians are working to develop a mathematical understanding of the relationship based on physicists' intuition. Mirror symmetry is also a fundamental tool for doing calculations in string theory, and it has been used to understand aspects of quantum field theory, the formalism that physicists use to describe elementary particles. Major approaches to mirror symmetry include the homological mirror symmetry program of Maxim Kontsevich and the SYZ conjecture of Andrew Strominger, Shing-Tung Yau, and Eric Zaslow.

Read more: https://en.wikipedia.org/wiki/Mirror_symmetry_(string_theory)

_______________________________ Today's selected anniversaries:

1671:

Irish-born Colonel Thomas Blood was caught trying to steal the English Crown Jewels from the Tower of London. https://en.wikipedia.org/wiki/Thomas_Blood

1877:

An 8.5 Ms earthquake struck the northern portion of Chile, resulting in the death of 2,541 people, including victims of the ensuing tsunami as far away as Hawaii and Japan https://en.wikipedia.org/wiki/1877_Iquique_earthquake

1949:

Rainier III became Prince of Monaco, beginning a 56-year reign, which would make him one of the longest ruling monarchs of the 20th century. https://en.wikipedia.org/wiki/Rainier_III,_Prince_of_Monaco

1964:

Ngô Đình Cẩn, de facto ruler of central Vietnam under his brother President Ngô Đình Diệm before the family's toppling, was executed. https://en.wikipedia.org/wiki/Ng%C3%B4_%C4%90%C3%ACnh_C%E1%BA%A9n

2004:

Akhmad Kadyrov, the first President of the Chechen Republic, and about 30 others were killed by a bomb during a World War II memorial victory parade in Grozny. https://en.wikipedia.org/wiki/Akhmad_Kadyrov

_____________________________ Wiktionary's word of the day:

green gown: (now archaic, historical) A dress that has been stained green from rolling in the grass; generally with allusion to sexual activity, especially a woman's loss of virginity. https://en.wiktionary.org/wiki/green_gown

___________________________ Wikiquote quote of the day:

 Man is a substantial emigrant on a pilgrimage of being, and it is accordingly meaningless to set limits to what he is capable of being.   --José Ortega y Gasset https://en.wikiquote.org/wiki/Jos%C3%A9_Ortega_y_Gasset