8 (number)
From Free net encyclopedia
| Cardinal | 8 eight |
| Ordinal | 8th eighth |
| Numeral system | octal |
| Factorization | <math> 2^3 </math> |
| Divisors | 1, 2, 4, 8 |
| Roman numeral | VIII |
| Unicode representation of Roman numeral | Ⅷ, ⅷ |
| prefixes | octa-/oct- (from Greek) |
| Binary | 1000 |
| Octal | 10 |
| Duodecimal | 8 |
| Hexadecimal | 8 |
| Hebrew | ח (Het) |
8 (eight) is the natural number following 7 and preceding 9.
Contents |
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 4 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.
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 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 Arabic 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, Image:TextFigs148.png.
In science
- The atomic number of oxygen.
- The number of allotropes of carbon.
- In physics, the second magic number.
- In particle physics, the eightfold way is used to classify sub-atomic particles.
Astronomy
- Messier object M8, a magnitude 5.0 nebula in the constellation Sagittarius.
- The New General Catalogue object NGC 8, a double star in the constellation Pegasus
- The Saros number of the solar eclipse series which began on 2579 BCE March 7 and ended on 1281 BCE April 26. The duration of Saros series 8 was 1298.1 years, and it contained 73 solar eclipses.
- The Saros number of the lunar eclipse series which began on 2512 BCE July 27 and ended on 961 BCE February 13. The duration of Saros series 7 was 1550.6 years, and it contained 87 lunar eclipses.
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.
- There are eighty-eight (88) keys on a piano.
- Songs with the number eight in their title include the Byrds's Eight Miles High and the Beatles' Eight Days a Week.
- Dream Theater's eighth album Octavarium contains many different references to the number eight, including the number of songs and various aspects of the music and cover artwork.
In sports
- In chess, each side has eight pawns; see also Eight queens puzzle
- In rugby union the number eight central back row position wears the 8 shirt.
- In the Nextel Cup series, 8 is Dale Earnhardt Jr.'s car number.
- In baseball, eight represents the center fielder's position.
- Eight ball billiards is played with 15 balls; the black ball numbered 8 is 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.
- The retired numbers of former baseball players Yogi Berra, Willie Stargell, Carl Yastrzemski, Joe Morgan, Gary Carter, and Cal Ripken, Jr.
- The number of Russian hockey player and current member of the NHL's Washington Capitals, Alexander Ovechkin.
- In Rowing an eight refers to a sweep oar boat with eight rowers plus a coxswain.
In technology
- Many (mostly historic) computer architectures are eight-bit, among them the Nintendo Entertainment System.
- 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.
In folklore, mythology or religion
- Eight (八, formal writing 捌, pinyin bā) is considered a lucky number in Chinese culture because it sounds like the word "prosper" (發 pinyin fā).
- The wheel of life has eight spokes.
- The Noble Eightfold Path in the Buddhist faith has eight steps.
- In Astrology, Scorpio is the 8th astrological sign of the Zodiac.
- Several groups of "Eight Immortals"
- Mormons (Church of Jesus Christ of Latter-day Saints) believe that humankind are responsible for their actions by the age of 8. Before that age children are not able to sin and are therefore exempt from judgement for their actions. Mormons believe that if a person dies before the age of 8 that they will automatically inherit the Celestial Kingdom.
- In numerology, 8 is the number of building, and in some theories, also the number of destruction.
In measurement
- In liquid measurement (U.S. customary units), there are 8 fluid ounces in a cup, 8 pints in a gallon, and 8 tablespoons in a gill.
- There are 8 furlongs in a mile.
- In cooking recipies, there are approximately 8 pinches to a teaspoon.
In other fields
Image:ICS Eight.svg Image:Sxc 8.jpg
- Eight babies delivered in one birth are called octuplets. The first set of eight surviving babies, the Louis-Chukwu Octuplets, were born in 1998.
- All spiders, and more generally all arachnids, have eight legs. An octopus has eight tentacles.
- Timothy Leary identified a hierarchy of eight levels of consciousness.
- October was the eighth month in the Roman calendar; August is currently the eighth month.
- 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.
- 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'.
- "Eight maids a-milking" is the gift on the eighth day of Christmas in the "Twelve days of Christmas" carol.
- I-8 is the designation of the US interstate highway that runs from San Diego, California to Casa Grande, Arizona.
- 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.
- 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.
- The ordinal adjective is octonary.
- Using hyperbole, the Beatles sang about loving their addressee "Eight Days a Week". Also from music is the 8-track cartridge.
- 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 in vanity plates.
- War of the Eight Princes
- The silver piece of eight was coined in the Spanish Empire and moved trade around the world.
- The symbol for infinity looks like a fallen eight.
- A figure 8 is the common name of a geometric shape, often used in the context of sports, such as skating.
- Eight Principles of Yong
- Lewis Carrolls poem The Hunting of the Snark has 8 "fits" (cantos), which is noted in the full name "The Hunting of the Snark - An Agony, in Eight Fits.
- "Section 8" is common U.S. slang for "crazy", based on the U.S. military's Section 8 discharge for mentally unfit personnel.
- 8 apparitions appear to Macbeth in Act 4 scene 1 of Shakespeare's Macbeth as representations of the 8 descendents of Banquo who will be king.
- Historical years: 8 A.D., 8 B.C., or 1908
- 8 is one of the "Lost Numbers" on the television show, Lost, along with 4, 15, 16, 23, and 42.gn:8
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