Einstein's BirthDay is Pi Day

Pi, Greek letter (π), is the symbol for the ratio of the

circumference of a circle to its diameter. Pi Day is celebrated by math enthusiasts around the world on March 14th. Pi = 3.1415926535…

With the use of computers, Pi has been calculated to over 1 trillion digits past the decimal. Pi is an irrational number meaning it will continue infinitely without repeating. The symbol for pi was first used in 1706 by William Jones, but was popular after it was adopted by the Swiss mathematician Leonhard Euler in 1737. Pi Day and Pi Approximation Day are two holidays held to celebrate the mathematical constant π  (pi) (in the mm/dd date notation: 3/14); since 3, 1 and 4 are the first three digits of π. March 14 is also the birthday of Albert Einstein and the two events are sometimes celebrated together.

Pi Approximation Day is observed on July 22, because of Archimedes’ popular approximation of π being 22/7. However, this may be considered misleading, as all cited dates are “approximation days” (as π is an irrational number) and 22/7 is actually a closer approximation of π than 3.14 is. Typically, March 14 is more popular for countries using the month/day format (22/7 being an impossible date in this format), and the 22nd of July is more popular for countries using the day/month format (since 3/14 and 31/4 are impossible dates in this format). Sometimes Pi Minute is also celebrated; this occurs twice on March 14 at 1:59 a.m. and 1:59 p.m. If π is truncated to seven decimal places, it becomes 3.1415926; making March 14 at 1:59:26 p.m., Pi Second (or sometimes March 14, 1592 at 6:53:58 a.m.). If 24-hour time is used, Pi Minute occurs once, on March 14 (3/14) at 1:59.

There are a large variety of ways of celebrating Pi Day and most of them include eating pie and discussing the relevance of π. The first Pi Day celebration was held at the San Francisco Exploratorium in 1988, with staff and public marching around one of its circular spaces, then consuming fruit pies. The museum has since added pizza to its Pi Day menu. The founder of Pi Day was Larry Shaw, a now-retired physicist at the Exploratorium who still helps out with the celebrations. The Massachusetts Institute of Technology often mails its acceptance letters to be delivered to prospective students on Pi Day.

Some also celebrate alternative Pi Days and/or Pi Approximation Days in addition to the two listed above; these can fall on any of several dates:

* March 4: When 14% of the 3rd month has elapsed.
* April 26: The Earth has traveled two radians of its orbit on this day (April 25 in leap years), reckoning from the start of the civil year on January 1. Thus the entire orbit divided by the distance traveled equals π; two radians equals 1⁄π of our orbit. This is celebrated exactly on the 41st second of the 23rd minute of the 4th hour on April 26 or the 116th day. (In leap years, it is celebrated exactly on the 3rd second of the 2nd minute of the 12th hour on April 25 or the 116th day.) This celebration is not a Pi Approximation Day; many, mathematicians included, celebrate April 26 as Pi Day and say that it should be the official Pi Day.
* November 10: The 314th day of the year (November 9 in leap years).
* December 21, 1:13 p.m.: The 355th day of the year (December 20 in leap years), celebrated at 1:13 for the Chinese approximation 355/113.

Pi Day Births

* 1638 – Johann Georg Gichtel, German mystic (d. 1710)
* 1681 – Georg Philipp Telemann, German composer (d. 1767)
* 1790 – Ludwig Emil Grimm, German painter and engraver (d. 1863)
* 1801 – Kristjan Jaak Peterson, first Estonian poet (d. 1822)
* 1804 – Johann Strauss, Sr., Austrian composer (d. 1849)
* 1807 – Josephine of Leuchtenberg, queen of Sweden and Norway (d. 1876)
* 1813 – Joseph Philo Bradley, U.S. Supreme Court Justice (d. 1892)
* 1822 – Teresa of the Two Sicilies, Empress of Brazil (d. 1889)
* 1823 – Théodore de Banville, French writer (d. 1891)
* 1835 – Giovanni Schiaparelli, Italian astronomer (d. 1910)
* 1837 – Charles Ammi Cutter, American librarian (d. 1903)
* 1844 – King Umberto I of Italy, (d. 1900)
* 1851 – John Sebastian Little, American politician and congressman (d. 1916)
* 1853 – Ferdinand Hodler, Swiss painter (d. 1918)
* 1854 – Paul Ehrlich, German scientist, Nobel laureate (d. 1915)
* 1854 – Alexandru Macedonski, Romanian writer (d. 1920)
* 1854 – John Lane, British publisher (d. 1925)
* 1854 – Thomas R. Marshall, 28th Vice President of the United States of America (d. 1925)
* 1862 – Vilhelm Bjerknes, Norwegian physicist (d. 1951)
* 1863 – Casey Jones, American railroad engineer (d. 1900)
* 1866 – Alexey Troitsky, Russian chess problemist (d. 1942)
* 1869 – Algernon Blackwood, British writer (d. 1951)
* 1879 – Albert Einstein, German-born physicist, Nobel Prize laureate (d. 1955)
* 1880 – Princess Thyra, daughter of Frederick VIII of Denmark (d. 1945)
* 1882 – Waclaw Sierpinski, Polish mathematician (d. 1969)
* 1885 – Raoul Lufbery, American World War I pilot (d. 1918)
* 1886 – Firmin Lambot, Belgian cyclist (d. 1964)
* 1887 – Sylvia Beach, American publisher (d. 1962)
* 1887 – Charles Reisner, American silent actor and film director (d. 1962)
* 1888 – Marc-Aurèle Fortin, Quebec painter (d. 1970)
* 1894 – Osa Johnson, American explorer (d. 1953)
* 1898 – Arnold Chikobava, Georgian linguist (d. 1985)
* 1899 – K.C. Irving, Canadian industrialist (d. 1992)
* 1903 – Mustafa Barzani, Kurdish politician (d. 1979)
* 1903 – Adolph Gottlieb American painter (d. 1974)
* 1904 – Doris Eaton Travis, American actress, Ziegfeld girl
* 1905 – Raymond Aron, French philosopher (d. 1983)
* 1908 – Ed Heinemann, American aircraft designer (Douglas Aircraft) (d. 1991)
* 1908 – Philip Conrad Vincent, British motorcycle pioneer (Vincent Black Shadow, Vincent Rapide and Vincent Black Lightning) (d. 1979)
* 1908 – Maurice Merleau-Ponty, French phenomenological philosopher (d. 1961)
* 1912 – Les Brown, American bandleader (d. 2001)
* 1912 – Cliff Bastin, English footballer (d. 1991)
* 1912 – Charles Van Acker, Belgian racing driver (d. 1998)
* 1912 – W. Willard Wirtz, American administrator
* 1914 – Lee Elhardt Hays, American folksinger (d. 1981)
* 1914 – Bill Owen, British actor (d. 1999)
* 1914 – Lee Petty, American race car driver (d. 2000)
* 1915 – Alexander Brott, Canadian conductor and composer (d. 2005)
* 1916 – Horton Foote, American author, playwright and screenwriter (d. 2009)
* 1918 – Dennis Patrick, American actor (d. 2002)
* 1920 – Hank Ketcham, American cartoonist (d. 2001)
* 1921 – S. Truett Cathy, founder of Chick-fil-A
* 1922 – Les Baxter, American musician and composer (d. 1996)
* 1923 – Diane Arbus, American photographer (d. 1971)
* 1925 – William Clay Ford, Sr., American owner of the Detroit Lions
* 1925 – Francis A. Marzen, American Catholic prelate (d. 2004)
* 1928 – Frank Borman, American astronaut and CEO
* 1928 – Félix Rodríguez de la Fuente, Spanish populariser environmentalist (d. 1980)
* 1931 – Phil Phillips, American singer and songwriter
* 1932 – Naina Yeltsina, Russia’s first First Lady
* 1933 – Sir Michael Caine, British actor
* 1933 – René Felber, former member of the Swiss Federal Council
* 1933 – Quincy Jones, American musician and composer
* 1934 – Eugene Cernan, American astronaut
* 1934 – Paul Rader, the 15th General of The Salvation Army
* 1936 – Bob Charles, New Zealand golfer
* 1939 – Raymond J. Barry, American actor
* 1939 – Bertrand Blier, French film director and screenwriter
* 1939 – Stavros Xarhakos, Greek composer
* 1939 – Pilar Bardem, Spanish actress
* 1941 – Wolfgang Petersen, German director
* 1942 – Rita Tushingham, British actress
* 1944 – Bobby Smith, English professional footballer and manager
* 1944 – Vaclav Nedomansky, Czech hockey player
* 1943 – Anita Morris, American actress (d. 1994)
* 1945 – Jasper Carrott, British comedian
* 1945 – Michael Martin Murphey, American country music singer
* 1945 – Walter Parazaider, American saxophonist (Chicago)
* 1945 – Herman van Veen, Dutch singer and theatre performer
* 1946 – Steve Kanaly, American actor
* 1946 – Wes Unseld, American basketball player
* 1947 – Pam Ayres, British poet
* 1947 – William J. Jefferson, American politician
* 1948 – Tom Coburn, American politician, junior senator from Oklahoma
* 1948 – Billy Crystal, American actor and comedian
* 1949 – Michael Stedman, British World War I Historian and Author
* 1950 – Rick Dees, American disc jockey
* 1951 – Jerry Greenfield, American co-founder of Ben & Jerry’s ice cream
* 1956 – Jonathan Bowen, British computer scientist
* 1956 – Colin Ayre, British football player
* 1957 – Andrew Robinson, British author
* 1957 – Tad Williams, American author
* 1958 – Albert II, Prince of Monaco
* 1959 – Tamara Tunie, American actress
* 1959 – Brian Whitfield, former South African cricketer
* 1960 – Kirby Puckett, American baseball player (d. 2006)
* 1961 – Greg Anderson, American NHRA driver
* 1961 – Penny Johnson Jerald, American actress
* 1961 – Hiro Matsushita, Japanese racing driver
* 1962 – Narumi Tsunoda, Japanese voice actress
* 1963 – Bruce Reid, Australian cricketer
* 1964 – Dario Bisso, Italian conductor
* 1965 – James Kevin Brown, American baseball player
* 1965 – Catherine Dent, American actress
* 1965 – Aamir Khan, Indian actor
* 1965 – Kiana Tom, American fitness guru and model
* 1965 – Kevin Williamson, American screenwriter
* 1966 – Elise Neal, American actress
* 1967 – Melissa Reeves, American actress
* 1968 – Megan Follows, Canadian actress
* 1969 – Des Coleman, English actor and presenter
* 1969 – Larry Johnson, American basketball player
* 1970 – Ebru Kavaklıoğlu, Russian athlete
* 1970 – Meredith Salenger, American actress
* 1974 – Patrick Traverse, Canadian ice hockey player
* 1974 – Grace Park, Canadian actress of Korean descedent
* 1975 – Stephen Harper, British/English footballer
* 1975 – Johan Paulik, Slovak porn star
* 1975 – Wendy Rice, American actress
* 1975 – Rico Yan, Filipino actor (d. 2002)
* 1976 – Merlin Santana, American actor (d. 2002)
* 1976 – Daniel Gillies, Canadian born New Zealand actor
* 1977 – Aki Hoshino, Japanese model
* 1978 – Pieter van den Hoogenband, Dutch swimmer
* 1978 – Carlo Giuliani, Italian anarchist (d. 2001)
* 1979 – Nicolas Anelka, French footballer
* 1979 – Chris Klein, American actor
* 1979 – Love, Angolan footballer
* 1979 – Sead Ramović, German-born Bosnian footballer
* 1979 – Anthony Carelli, Italian-American professional wrestler
* 1980 – Aaron Brown, British/English footballer
* 1980 – Matteo Grassotto, Italian racing driver
* 1980 – Ben Herring, New Zealand rugby union footballer
* 1980 – Mercedes McNab, Canadian-born actress
* 1981 – Bobby Jenks, American baseball player
* 1981 – Mei-Ting Sun, Chinese-born pianist
* 1982 – Carlos Marinelli, Argentine footballer
* 1982 – François Sterchele, Belgian footballer (d. 2008)
* 1982 – Kate Maberly, British actor, Singer Songwriter
* 1983 – Bakhtiyar Artayev, Kazakh boxer
* 1983 – Taylor Hanson, American musician, member of Hanson
* 1984 – Liesel Matthews, American former child actress
* 1985 – Eva Angelina, American porn star
* 1985 – Idaira, Spanish singer
* 1985 – Brianna Love, American porn Star
* 1986 – Jamie Bell, British actor
* 1986 – Elton Chigumbura, Zimbabwean cricketer
* 1986 – Andy Taylor, British/English footballer
* 1988 – Stephen Curry, American basketball player
* 1989 – Colby O’Donis, American musician
* 1992 – Jasmine Murray, American singer
* 1993 – Julienne Irwin, American singer