Celeritas
Encyclopedia
Celeritas is a Latin
word, translated as "swiftness" or "speed". It is often given as the origin of the symbol c, the universal notation for the speed of light
in a vacuum
, as popularized in Albert Einstein
's famous equation E = mc²
. In SI units, the speed of light in a vacuum is defined as 299,792,458 meters per second (1,079,252,848.8 km/h).
elsewhere for a different energy). The first use of the letter c as a symbol for the speed of light was in an 1856 paper by Wilhelm Eduard Weber
and Rudolf Kohlrausch
. Weber used the notation to stand for constant, and it later become known as Weber's constant
. At the turn of the 20th century, c was popularised by influential physicists such as Max Planck
and Hendrik Lorentz
. In 1907, Einstein switched to this notation in his papers.
A 1959 essay by science fiction and popular science author Isaac Asimov
is the first reference to c standing for celeritas, though he cited no evidence to support this. It is now standard to see "c is for celeritas". David Bodanis
, in his popular science book E=mc²: A Biography of the World's Most Famous Equation, states that "the speed of light
has this unsuspected letter for its name probably out of homage for the period before the mid 1600s when science was centered around Italy, and Latin was the language of choice, Celeritas is the Latin word for swiftness."
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
word, translated as "swiftness" or "speed". It is often given as the origin of the symbol c, the universal notation for the speed of light
Speed of light
The speed of light in vacuum, usually denoted by c, is a physical constant important in many areas of physics. Its value is 299,792,458 metres per second, a figure that is exact since the length of the metre is defined from this constant and the international standard for time...
in a vacuum
Vacuum
In everyday usage, vacuum is a volume of space that is essentially empty of matter, such that its gaseous pressure is much less than atmospheric pressure. The word comes from the Latin term for "empty". A perfect vacuum would be one with no particles in it at all, which is impossible to achieve in...
, as popularized in Albert Einstein
Albert Einstein
Albert Einstein was a German-born theoretical physicist who developed the theory of general relativity, effecting a revolution in physics. For this achievement, Einstein is often regarded as the father of modern physics and one of the most prolific intellects in human history...
's famous equation E = mc²
Mass-energy equivalence
In physics, mass–energy equivalence is the concept that the mass of a body is a measure of its energy content. In this concept, mass is a property of all energy, and energy is a property of all mass, and the two properties are connected by a constant...
. In SI units, the speed of light in a vacuum is defined as 299,792,458 meters per second (1,079,252,848.8 km/h).
History
In the 19th century, V was commonly used to denote the speed of light. Einstein used this notation in his famous 1905 papers. Thus, Einstein originally wrote his most famous equation as m = L / V2 (he used EE
E is the fifth letter and a vowel in the basic modern Latin alphabet. It is the most commonly used letter in the Czech, Danish, Dutch, English, French, German, Hungarian, Latin, Norwegian, Spanish, and Swedish languages.-History:...
elsewhere for a different energy). The first use of the letter c as a symbol for the speed of light was in an 1856 paper by Wilhelm Eduard Weber
Wilhelm Eduard Weber
Wilhelm Eduard Weber was a German physicist and, together with Carl Friedrich Gauss, inventor of the first electromagnetic telegraph.-Early years:...
and Rudolf Kohlrausch
Rudolf Kohlrausch
Rudolf Hermann Arndt Kohlrausch was a German physicist.-Biography:He was a native of Göttingen, the son of educator Heinrich Friedrich Theodor Kohlrausch...
. Weber used the notation to stand for constant, and it later become known as Weber's constant
Speed of light
The speed of light in vacuum, usually denoted by c, is a physical constant important in many areas of physics. Its value is 299,792,458 metres per second, a figure that is exact since the length of the metre is defined from this constant and the international standard for time...
. At the turn of the 20th century, c was popularised by influential physicists such as Max Planck
Max Planck
Max Karl Ernst Ludwig Planck, ForMemRS, was a German physicist who actualized the quantum physics, initiating a revolution in natural science and philosophy. He is regarded as the founder of the quantum theory, for which he received the Nobel Prize in Physics in 1918.-Life and career:Planck came...
and Hendrik Lorentz
Hendrik Lorentz
Hendrik Antoon Lorentz was a Dutch physicist who shared the 1902 Nobel Prize in Physics with Pieter Zeeman for the discovery and theoretical explanation of the Zeeman effect...
. In 1907, Einstein switched to this notation in his papers.
A 1959 essay by science fiction and popular science author Isaac Asimov
Isaac Asimov
Isaac Asimov was an American author and professor of biochemistry at Boston University, best known for his works of science fiction and for his popular science books. Asimov was one of the most prolific writers of all time, having written or edited more than 500 books and an estimated 90,000...
is the first reference to c standing for celeritas, though he cited no evidence to support this. It is now standard to see "c is for celeritas". David Bodanis
David Bodanis
David Bodanis is a popular science writer. Originally from Chicago, he lived in France for ten years. He is now based in London.His first commercial success The Secret House: 24 hours in the strange & wonderful world in which we spend our nights and days established him with the literary style of...
, in his popular science book E=mc²: A Biography of the World's Most Famous Equation, states that "the speed of light
Speed of light
The speed of light in vacuum, usually denoted by c, is a physical constant important in many areas of physics. Its value is 299,792,458 metres per second, a figure that is exact since the length of the metre is defined from this constant and the international standard for time...
has this unsuspected letter for its name probably out of homage for the period before the mid 1600s when science was centered around Italy, and Latin was the language of choice, Celeritas is the Latin word for swiftness."
External links
- http://math.ucr.edu/home/baez/physics/Relativity/SpeedOfLight/c.html
- http://www.zbp.univie.ac.at/meldungen/2005-01-31/02/ download 1905 papers in original German