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The name “googol” was invented by a child who was asked to think up a name for a very big number, namely, 1 with a hundred zeros after it. He was very certain that this number was not infinite, and therefore equally certain that it had to have a name.
—Edward Kasner, James R Newman, Mathematics and the Imagination (1940)
Not to be confused with goggol.

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Googol is an official name for a large number, defined as 10100 or 1 followed by 100 zeroes.[1][2][3] It is also called "ten duotrigintillion" using the short scale.[4][5] It is 101 digits long. It is the namesake of googology, and serves as the benchmark on what constitutes a large number.

Coined in the year 1920,[6] it has become very famous as a generic example of a large number, and is what the field of googology and the search engine Google are named after.

## History

The term was coined by Edward Kasner's nine-year-old nephew, Milton Sirotta in 1920. It was perhaps first published in New Names in Mathematics (1937). The name was most likely influenced by name of the title character of the American comic strip Barney Google and Snuffy Smith, which was very popular at the time. Barney Google's name was in turn inspired by Vincent Vickers' 1939 children's book The Google Book.

## Properties

The googol is equal to ten duotrigintillion in the short scale, or ten sexdecilliard in the long scale.[7] Googol can be expressed as {10,100} in BEAF, or as E100, E100#1, or E2#2 in Hyper-E notation.

Sbiis Saibian has given the alternative name guppyding.[8]

Aarex Tiaokhiao coined the names unoohol, 100-noogol, and booiolplex for this number.[9]

Username5243 coined the name goodolplex for this number, and it's equal to 10[1]10[1]2 in Username5243's Array Notation.[10]

SuperJedi224 coined the name decigol for this number.[11] He also calls it cyplex, using André Joyce's naming system.

BlankEntity calls this number Blag.[12]

DeepLineMadom calls the number troogol, and is equal to 10[3]100 in DeepLineMadom's Array Notation[13]. It should not be confused with the much larger Bowers' troogol. The user also calls this number gargogol.[14]

SeveralLegend9998 calls this number giddol, and it's equal to 10(2)100 in Hyperdimensional Array Notation.[15]

## Size

There are a mere 1080 elementary particles in the observable universe, so googol has little use when measuring real-world quantities. However. it is still much less than the number of Planck volumes in the observable universe (which is about 10185), so it still has some real-world meaning. Sbiis Saibian showed that a googol particles in a tightly packed sphere would still have a diameter of 5.6 quadrillion meters, or half a light-year.[16]

A cube with edge length 35mm contains about a googol Planck volumes.[17]

Googol is comparable to some numbers produced by combinatorics. For example, 70 factorial (the number of ways 70 distinct objects can be arranged in a row) is about 20% larger than 10100.

A googol seconds is 316 novemvigintillion years, about a sesvigintillion (1081) times the estimated age of the universe. A googol angstroms is approximately 100 tresvigintillion light-years.

It takes approximately 317 novemvigintillion years to count to a googol one integer at a time. Counting by googols, half googols, or duotrigintillions, of course, one could count there faster but it is not considered kosher in hide-and-seek or googology.

The time it takes for the black hole TON 618 to fully decay due to hawking radiation is about a googol years.[18]

The first constructive solution for Tarski's circle-squaring problem involve pieces numbering in small powers of a googol. These pieces are also not Jordan-measurable and require precise mathematical description to describe. [19]

## Approximations in other notations

Notation Lower bound Upper bound
Scientific notation $$1\times10^{100}$$
Arrow notation $$10\uparrow100$$
Steinhaus-Moser Notation $$56[3]$$ $$57[3]$$
Copy notation $$9[100]$$ $$1[101]$$
Factorial 69.957574457! 69.957574458!
Chained arrow notation $$10→100$$
BEAF $$\{10,100\}$$
Bashicu matrix system with respect to version 4 $$(0)(0)(0)(0)(0)[1333]$$ $$(0)(0)(0)(0)(0)[1334]$$
Bird's array notation $$\{10,100\}$$
Fast-growing hierarchy $$f_2(323)$$ $$f_2(324)$$
Hardy hierarchy $$H_{\omega^2}(323)$$ $$H_{\omega^2}(324)$$
Slow-growing hierarchy $$g_{\omega^{\omega^2}}(10)$$

## Cultural impact

The definition of googol, googolplex, and similar numbers eventually branched into the field of googology, the study of, nomenclature of, and creation of notations for large numbers.

Larry Page and Sergey Brin, the founders of the Google search engine, named their company after a pun on googol, as their goal is to cache the mass of data that makes up the World Wide Web.[20]

Googology Wiki has a tongue-in-cheek goal to reach 10100 articles, which is probably impossible.

Googol was the subject of the £1 million question in a 2001 episode of the British version of the quiz show Who Wants To Be A Millionaire?, where contestant Charles Ingram cheated his way to the jackpot with the assistance of an aide in the audience.

## Sources

Googol and related numbers

Originals: googol · googolplex
Cockburn's examples: gargoogolplex · fzgoogolplex · (mega)fugagoogolplex
Googol-n-plex: googolduplex · googoltriplex · -quadriplex · -quinplex · -sextiplex · -septiplex · -octiplex · -noniplex · -deciplex · -centiplex
Googol-103n-plex: googolmilliplex · -megaplex · -gigaplex · -teraplex · -petaplex · -exaplex · -zettaplex · -yottaplex · -xennaplex · -vekaplex · -mekaplex
Bowers' extensions: giggol · gaggol · geegol · boogol · biggol · troogol · goobol · more...
Saibian's extensions: googol-minutia · googolchime · googoltoll · googolgong · grangol · greagol · gigangol · gugold · graatagold · gugolthra · throogol · godgahlah · tethrathoth · more...
Miscellany: googolbang (10100!) · googolminex (10^-10100) · googolteen · googolty · great googol(plex) · gooprol · little googol/googolbit · zootzootplex

-minutia group
n-ary numbers with multipliers
Eyelash mite group: eyelash mite-speck · eyelash mite-crumb · eyelash mite-chunk · (binary/ternary/octal)eyelash mite · eyelash mite-bunch · eyelash mite-crowd · eyelash mite-swarm
Dust mite group: dust mite-speck · dust mite-crumb · dust mite-chunk · (binary/ternary/octal)dust mite · dust mite-bunch · dust mite-crowd · dust mite-swarm
Cheese mite group: cheese mite-speck · cheese mite-crumb · cheese mite-chunk · (binary/ternary/octal)cheese mite · cheese mite-bunch · cheese mite-crowd · cheese mite-swarm
Clover mite group: clover mite-speck · clover mite-crumb · clover mite-chunk · (binary/ternary/octal)clover mite · clover mite-bunch · clover mite-crowd · clover mite-swarm
Pipsqueak group: (binary/ternary/octal)pipsqueak
Little squeaker group: (binary/ternary/octal)little squeaker
Small fry group: (binary/ternary/octal)small fry
Guppy group: (binary/ternary/octal)guppyspeck · (binary/ternary/octal)guppycrumb · (binary/ternary/octal)guppychunk · (ternary/quaternary/quinary/duodecimal/hexadecimal/vigesimal/sexagesimal)guppy(bit/byte)
Minnow group: (binary/ternary/octal)minnowspeck · (binary/ternary/octal)minnowcrumb · (binary/ternary/octal)minnowchunk · (ternary)minnow(bit/byte)
Goby group: (binary/ternary/octal)gobyspeck · (binary/ternary/octal)gobycrumb · (binary/ternary/octal)gobychunk · (ternary)goby(bit/byte)
Jumbo shrimp group: (binary/ternary/octal)jumbo shrimp
Lightweight group: (binary/ternary/octal)lightweight
Ogol group: (binary/ternary/octal)ogolspeck · (binary/ternary/octal)ogolcrumb · (binary/ternary/octal)ogolchunk · (ternary/quaternary/quinary/duodecimal/hexadecimal/vigesimal/sexagesimal)ogol(bit/byte)
Tiny twerpuloid group: (binary/ternary/octal)tiny twerpuloid
Googol group: (binary/ternary/octal)googolspeck · (binary/ternary/octal)googolcrumb · (binary/ternary/octal)googolchunk · (ternary/quaternary/quinary/duodecimal/hexadecimal/vigesimal/sexagesimal)googol*(bit/byte) · googolbunch · googolcrowd · googolswarm
Eceton group: ecetonspeck · ecetoncrumb · ecetonchunk · ecetonbunch · ecetoncrowd · ecetonswarm
*Not Saibian's
Numbers with base-multipliers
Numbers with -plex

Higher basic series
2-entry series
Linear series
Two-row series

Note: The readers should be careful that numbers defined by Username5243's Array Notation are ill-defined as explained in Username5243's Array Notation#Issues. So, when an article refers to a number defined by the notation, it actually refers to an intended value, not an actual value itself (for example, a[c]b = $$a \uparrow^c b$$ in arrow notation). In addition, even if the notation is ill-defined, a class category should be based on an intended value when listed, not an actual value itself, as it is not hard to fix all the issues from the original definition, hence it should not be removed.
Googol — Greagol
Greagol — Gugold
Throogol — Godgahlah-ex-grand godgahlah

Numbers By SuperJedi224

Fibonacci Numbers

Level One

Level Two

#*

#**

H#*

#*{}

#*<<>>

H#*<<>>

Bingol series

Based on the Faxul

Other factorials

Googovipleccix family

Graham Sequence Numbers

-Illion numbers