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8 (eight) is the natural number following 7 and preceding 9. The SI prefix for 10008 is yotta (Y), and for its reciprocal yocto (y).
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In mathematics
It is a composite number, its proper divisors being 1, 2, and 4.
Eight is a power of two, being 23, or two cubed.
8 is the base of the octal number system, which is mostly used with computers. In octal, one digit represents 3 bits. In modern computers, a byte is a grouping of eight bits, also called an octet.
The number 8 is a Fibonacci number, being 3 plus 5. The next Fibonacci number is 13.
8 and 9 form a Ruth-Aaron pair under the second definition in which repeated prime factors are counted as often as they occur.
A polygon with eight sides is an octagon. Figurate numbers representing octagons (including eight) are called octagonal numbers. A polyhedron with eight faces is an octahedron.
Sphenic numbers always have exactly eight divisors.
8 is the dimension of the octonions and is the highest possible dimension of a normed division algebra.
The number 8 is involved with a number of interesting mathematical phenomena related to the notion of Bott periodicity. For example if is the direct limit of the inclusions of real orthogonal groups then . Clifford algebras also display a periodicity of 8. For example the algebra is isomorphic to the algebra of 16 by 16 matrices with entries in . We also see a period of 8 in the K theory of spheres and in the representation theory of the rotation groups, the latter giving rise to the 8 by 8 spinorial chessboard. All of these properties are closely related to the properties of the octonions.
The lowest dimensional even unimodular lattice is the 8-dimensional E8 lattice. Even positive definite unimodular lattice exist only in dimensions divisible by 8.
A figure 8 is the common name of a geometric shape, often used in the context of sports, such as skating
In binary code eight is 1000; in ternary code eight is 22; in quaternary numeral system code eight is 20; in quinary eight is 13; in senary eight is 12; in septenary eight is 11; in octal eight is 10; in novenary code and all codes above (such as decimal and hexadecimal) eight is 8. In Roman numerals eight is VIII.
A fallen or lying down 8 is used to represent infinity in mathematics. This interpretation of 8 may be related to the representation of the caduceus (where two snakes form several figure eights) as stability or balance of opposing forces.
Eight is the number of Thurston model geometries.
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In numeral systems
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Evolution of the glyph
In the beginning, various groups in India wrote eight more or less in one stroke as a curve that looks like an uppercase H with the bottom half of the left line and the upper half of the right line removed. At one point this glyph came close to looking like our modern five. With the western Ghubar Arabs, the similarity of the glyph to five was banished by connecting the beginning and the end of stroke together, and it was only a matter of the Europeans rounding the glyph that led to our modern eight.
In fonts with text figures, eight usually has an ascender, for example, .
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In science
The most stable allotrope of a sulfur molecule is made of eight sulfur atoms arranged in a rhombic form.
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Astronomy
As of 2006, in our solar system, eight of the bodies orbiting the Sun are considered to be planets.
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In religion
The Jewish religious rite of brit milah is held on a baby boy's eighth day of life
Hanukkah is an eight-day Jewish holiday that starts on the 25th day of Kislev
Members of The Church of Jesus Christ of Latter-day Saints believe that humans are responsible for their actions by the age of 8. Before that age, children lack sufficient knowledge to commit sin and are therefore exempt from judgment for their actions.
In Scientology, there are 8 dynamics of life. The eighth dynamic represents the Infinity, or God
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In superstition and divination
If each of the classical elements is assigned a cosmic projection, the resulting number (8) represents them.
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As a lucky or unlucky number
In numerology, 8 is the number of building, and in some theories, also the number of destruction
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In astrology
In the middle ages, 8 was the number of "unmoving" stars in the sky, and symbolized the perfectioning of incoming planetary energy
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In music
A note played for one-eighth the duration of a whole note is called an eighth note, or quaver
An octave, the interval between two notes with the same letter name (where one has double the frequency of the other), is so called because there are eight notes on a western scale between the two, including the notes themselves
There are eight musicians in an octet
Dream Theater's eighth album Octavarium contains many different references to the number 8, including the number of songs and various aspects of the music and cover artwork
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In sports
Eight ball billiards is played with 15 balls; the black ball numbered 8 being the most important one. Magic 8 Ball is a randomized process of predicting the future or answering various questions, packaged to resemble this ball and often sold as a fortune-telling device
In Rowing an eight refers to a sweep oar boat with eight rowers plus a coxswain.
The jersey number of Kobe Bryant from 1996-2006 (now is
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In technology
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On most phones, the 8 key is associated with the letters T, U, and V, but on the BlackBerry it is the key for B and N
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In measurement
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In foods
There is a brand of chocolates filled with peppermint-flavoured cream called "After Eight", referring to the time 8 p.m.
There are eight vegetables in V8 juice
In cooking recipes, there are approximately 8 pinches to a teaspoon
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In literature
In Terry Pratchett's Discworld series, eight is a holy number and is considered taboo. Eight is not safe to be said by wizards on the Discworld and is the number of Bel-Shamharoth. Also, there are eight days in a Disc week and eight colours in a Disc spectrum, the eighth one being Octarine
8 apparitions appear to Macbeth in Act 4 scene 1 of Shakespeare's Macbeth as representations of the 8 descendants of Banquo who will be king
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In slang
An Eighth is a common measurment of high grade marijuana, meaning an eighth of an ounce
Referring to the shape of the numeral, eight was represented in bingo slang, before political correctness, as "One Fat Lady". Eighty-eight was "Two Fat Ladies"
The numeral "8" is sometimes used in writing to represent the syllable "ate", as in writing "H8" for "hate", or "congratul8ons" for "congratulations". Avril Lavigne's song "Sk8er Boi" uses this convention in the title. Often found on vanity plates
In Colombia and Venezuela, "volverse un ocho" (meaning to tie oneself in a figure 8) refers to getting in trouble or contradicting one's self.
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In other fields
The ordinal adjective is octonary
October was the eighth month in the Roman calendar; currently August is the eighth month
Eight is the number of categories the VALS system uses to classify consumer groups, and the number of categories used by Fallon-McElligott's system for teen marketing
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Historical years
'''8 A.D.''', 8 B.C., 1908, 2008, etc.
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Reference
nah:Chicuēyi
vls:8 (getal)
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