How big is a googolplex? |
One googol is presumed to be greater than the number of elementary
particles in the observable universe, which has been variously
estimated from 1079 up to 1081. A googol is also greater than the
number of Planck times elapsed since the Big Bang which is
estimated at around 8 × 1060. Even a list of the state of every
particle at every measurable unit of time since the Big Bang would
have nowhere near a googolplex entries (max. around 8 ×
10141).
Since a googolplex is one followed by a googol zeroes, it would not
be possible to write down or store a googolplex in decimal
notation, even if all the matter in the known universe were
converted into paper and ink or disk drives. Indeed, if you had an
unlimited supply of ink and paper, you would need around 1020 times
the current age of universe to fully write down a googolplex.
Thinking of this another way, consider printing the digits of a
googolplex in unreadable, one-point font. TeX one-point font is
.3514598 mm per digit, which means it would take about 3.5 × 1096
meters to write in one-point font. The known universe is estimated
at 7.4 × 1026 meters in diameter, which means the distance to write
the digits would be about 4.7 × 1069 times the diameter of the
known universe. The time it would take to write such a number also
renders the task implausible: if a person can write two digits per
second, it would take around 1.1 × 1082 times the age of the
universe to write down a googolplex.
Thus in the physical world it is difficult to give examples of
numbers that compare closely to a googolplex. In analyzing quantum
states and black holes, physicist Don Page writes that "determining
experimentally whether or not information is lost down black holes
of solar mass ... would require more than 101076.96 measurements to
give a rough determination of the final density matrix after a
black hole evaporates".[2] In a separate article, Page shows that
the number of states in a black hole with a mass roughly equivalent
to the Andromeda Galaxy is in the range of a googolplex.[3]
In pure mathematics, the magnitude of a googolplex is not as large
as some of the specially defined extraordinarily large numbers,
such as those written with tetration, Knuth's up-arrow notation,
Steinhaus-Moser notation, or Conway chained arrow notation. Even
more simply, one can name numbers larger than a googolplex with
fewer symbols, for example,
999999, is much larger.
This last number can be expressed more concisely as 69 using
tetration, or 9↑↑6 using Knuth's up-arrow notation.
Some sequences grow very quickly; for instance, the first two
Ackermann numbers are 1 and 22=4; but then the third is 333, a
power tower of threes more than seven trillion high.
Yet, much larger still is Graham's number, perhaps the largest
natural number mathematicians actually have a use for.
A googolplex is a gigantic number that can be expressed compactly
because of nested exponentiation. Other procedures (like tetration)
can express large numbers even more compactly. The natural question
is: what procedure uses the smallest number of symbols to express
the biggest number? A Turing machine formalizes the notion of a
procedure or algorithm, and a busy beaver is the Turing machine of
size n that can write down the biggest possible number [1]. The
bigger n is, the more complex the busy beaver, hence the bigger the
number it can write down. For n=1, 2, 3, 4 and 5 the numbers
expressible are not huge, but research as of 2006 shows that for
n=6 the busy beaver can write down a number at least as big as
1.29\times10^{865}. [2] It is an open question whether the seventh
busy beaver can express a googolpl
One googol is presumed to be greater than the number of elementary
particles in the observable universe, which has been variously
estimated from 1079 up to 1081. A googol is also greater than the
number of Planck times elapsed since the Big Bang which is
estimated at around 8 × 1060. Even a list of the state of every
particle at every measurable unit of time since the Big Bang would
have nowhere near a googolplex entries (max. around 8 ×
10141).
Since a googolplex is one followed by a googol zeroes, it would not
be possible to write down or store a googolplex in decimal
notation, even if all the matter in the known universe were
converted into paper and ink or disk drives. Indeed, if you had an
unlimited supply of ink and paper, you would need around 1020 times
the current age of universe to fully write down a googolplex.
Thinking of this another way, consider printing the digits of a
googolplex in unreadable, one-point font. TeX one-point font is
.3514598 mm per digit, which means it would take about 3.5 × 1096
meters to write in one-point font. The known universe is estimated
at 7.4 × 1026 meters in diameter, which means the distance to write
the digits would be about 4.7 × 1069 times the diameter of the
known universe. The time it would take to write such a number also
renders the task implausible: if a person can write two digits per
second, it would take around 1.1 × 1082 times the age of the
universe to write down a googolplex.
Thus in the physical world it is difficult to give examples of
numbers that compare closely to a googolplex. In analyzing quantum
states and black holes, physicist Don Page writes that "determining
experimentally whether or not information is lost down black holes
of solar mass ... would require more than 101076.96 measurements to
give a rough determination of the final density matrix after a
black hole evaporates".[2] In a separate article, Page shows that
the number of states in a black hole with a mass roughly equivalent
to the Andromeda Galaxy is in the range of a googolplex.[3]
In pure mathematics, the magnitude of a googolplex is not as large
as some of the specially defined extraordinarily large numbers,
such as those written with tetration, Knuth's up-arrow notation,
Steinhaus-Moser notation, or Conway chained arrow notation. Even
more simply, one can name numbers larger than a googolplex with
fewer symbols, for example,
999999, is much larger.
This last number can be expressed more concisely as 69 using
tetration, or 9↑↑6 using Knuth's up-arrow notation.
Some sequences grow very quickly; for instance, the first two
Ackermann numbers are 1 and 22=4; but then the third is 333, a
power tower of threes more than seven trillion high.
Yet, much larger still is Graham's number, perhaps the largest
natural number mathematicians actually have a use for.
A googolplex is a gigantic number that can be expressed compactly
because of nested exponentiation. Other procedures (like tetration)
can express large numbers even more compactly. The natural question
is: what procedure uses the smallest number of symbols to express
the biggest number? A Turing machine formalizes the notion of a
procedure or algorithm, and a busy beaver is the Turing machine of
size n that can write down the biggest possible number [1]. The
bigger n is, the more complex the busy beaver, hence the bigger the
number it can write down. For n=1, 2, 3, 4 and 5 the numbers
expressible are not huge, but research as of 2006 shows that for
n=6 the busy beaver can write down a number at least as big as
1.29\times10^{865}. [2] It is an open question whether the seventh
busy beaver can express a googolpl
How big is a googolplex?