1) IN MATHMATICS:
8 is a composite number, its proper divisors being 1, 2, and 4. Eight is a power of two, being two cubed. It is the first cubed prime.
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.
Sphenic numbers (a positive integer which is the product of three distinct prime numbers) always have exactly eight divisors.
8 is the dimension of the octonions and is the highest possible dimension of a normed division algebra.
2) IN SCIENCE:
There are eight known B vitamins that play important roles in cell metabolism.
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 .
As of 2006, in our solar system, eight of the bodies orbiting the Sun are considered to be planets.
3) IN RELIGION:
In Christianity, it is allegoric to Christ's sacrifice on the cross and is the number of Beatitudes.
In Neopaganism, there are eight Sabbats, festivals, seasons, or spokes in the Wheel of the Year.
Hanukkah is an eight-day Jewish holiday that starts on the 25th day of Kislev .
The Noble Eightfold Path in the Buddhist faith has eight steps.
4) IN ASTROLOGY & SUPERSTITION :
In the middle ages, 8 was the number of "unmoving" stars in the sky, and symbolized the perfectioning of incoming planetary energy.
If each of the classical elements is assigned a cosmic projection, the resulting number ( 8 ) represents them.
In tarot, card No. 8 is "Strength" [
EDIT: In some decks it is Justice]
In numerology, 8 is the number of building, and in some theories, also the number of destruction.
5) IN THE ARTS:
There are eight notes in an octatonic scale.
8 apparitions appear to Macbeth in Act 4 scene 1 of Shakespeare's Macbeth as representations of the 8 descendants of Banquo
Songs with the number eight in their title include the Byrds's Eight Miles High and the Beatles' Eight Days a Week.
Lewis Carroll's 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
6) IN SPORTS & GAMING:
The following Hall of Fame baseball players wore number 8: Luke Appling, Yogi Berra, Gary Carter, Hazen Shirley "Kiki" Cuyler, Bill Dickey, Rick Ferrell, Chuck "Hoosier Hammer" Klein, Ernie Lombardi, Joe Morgan, Cal Ripken, Jr., Al Simmons, Willie Stargell, Paul Waner, and Carl Yastrzemski.
Eight ball billiards is played with 15 balls; the black ball numbered 8 being the most important one.
In chess, each side has eight pawns
In Rowing an eight refers to a sweep oar boat with eight rowers plus a coxswain.
7) IN CHINA:
The Eight Immortals are Chinese deities
War of the Eight Princes, was a war in Chinese history
There are Eight Principles of Yong in Chinese calligraphy
Eight is considered a lucky number in Chinese culture because it sounds like the word "prosper" or "wealth.
(Source)
