
42 - robinhouston
http://johncarlosbaez.wordpress.com/2013/05/25/42/
======
gmu3
Obviously the article is written for fun, but for those interested Douglas
Adams' answer to why 42 was:

"The answer to this is very simple. It was a joke. It had to be a number, an
ordinary, smallish number, and I chose that one. Binary representations, base
thirteen, Tibetan monks are all complete nonsense. I sat at my desk, stared
into the garden and thought '42 will do'. I typed it out. End of story."

~~~
Cushman
It's a bit silly he had to say this-- this is made very explicit in the books.
I feel like a lot of people missed the point of the whole exercise.

------
Arjuna
I always thought that this was interesting...

I am sure that many of you are familiar with Dr. Feynman's 7-part lecture
series entitled _The Character of Physical Law_ , which were part of the
"Messenger Lectures" [1], given at Cornell University in 1964.

In the first lecture, _Law of Gravitation - An Example of Physical Law_ ,
Feynman states the following:

"Question: what is the ratio of the gravitational force to the electrical
force? That is illustrated on the next slide.

The ratio of the gravitational attraction to the electrical repulsion is given
by a number with 42 digits, and goes off here: all this is written very
carefully out, so that's 42 digits.

Now, therein lies a very deep mystery: where could such a tremendous number
come from? That means if you ever had a theory from which both of these things
are to come, how could they come in such disproportion? From what equation has
a solution which has for one, two kinds of forces, an attraction and a
repulsion with that fantastic ratio? People have looked for such a large ratio
in other places.

They're looking for a large number.

They hope, for example, that there's another large number.

And if you want a large number why not take the diameter of the universe to
the diameter of a proton.

Amazingly enough, it also is a number with 42 digits." [2]

[1] <https://en.wikipedia.org/wiki/Messenger_Lectures>

[2] <https://www.youtube.com/watch?v=j3mhkYbznBk#t=48m11s>

~~~
jimmaswell
42 digits in base 10 though, and base 10 is just an arbitrary convention. It
can be more or less in other equally valid bases.

~~~
dylangs1030
Yes, but within that base it's significant. Just as within other bases the
corresponding number would be significant.

This is important because if you operate a system universally with the same
base, the significant number begins to take on an objective importance _intra-
system._

Stated another way, it's mathematical semantics, the same as arguing an idea
is not significant because you can express it in a multitude of different
languages, each having an arbitrary words.

Developing via Django (Python) or Rails (Ruby) is similarly predisposed to
making one think it's all relative, but when you look closely, the framework
doesn't matter at all - there are universal abstractions inherent in web
development.

The representation is arbitrary and insignificant, what is significant is what
the number or word represents, and what you can do by unraveling it.

~~~
alcuadrado
"Just as within other bases the corresponding number would be significant."

Numbers are independent from any base. You may mean the numeral in another
base, which would have a different number of digits.

But what is more important, note that not necessarily the two ratios from the
quote will have the same number of digits in another base.

~~~
dylangs1030
Yes, the numeral representation of the number is exactly what I mean, you
clarified my comment perfectly. Numbers are independent from any base.

------
quarterto
Hurwitz's automorphisms theorem always astounds me. 84 is such a weird number
to see in it. Fun fact: a group for which the maximum of 84(g-1) is reached is
called a Hurwitz group. The Monster Group a Hurwitz group. So there is a
Reimann surface of genus 9619255057077534236743570297163223297687552000000001
whose group of automorphisms (via orientation-preserving conformal mappings)
is the Monster group. I don't even want to start trying to imagine that
surface.

For more unlikely Monster Group fun, there's also
<http://en.wikipedia.org/wiki/Monstrous_moonshine>.

<http://en.wikipedia.org/wiki/Monster_group>
[http://en.wikipedia.org/wiki/Hurwitz%27s_automorphisms_theor...](http://en.wikipedia.org/wiki/Hurwitz%27s_automorphisms_theorem)

~~~
tel
The Monster made me a Platonist. Group classification is damn alien stuff.
It's like discovering Moby Dick except a million times larger and scarier,
buried in the dark depths between science and philosophy.

------
jmmcd
> But why is this stuff the answer to the ultimate question of life, the
> universe, and everything? I’m not sure, but I have a crazy theory. Maybe all
> matter and forces are made of tiny little strings!

Come now, be serious!

------
jpatokal
Handy reminder: All natural numbers are interesting.

<http://en.wikipedia.org/wiki/Interesting_number_paradox>

------
gonzo
This is where I point out that the answer was wrong.

In HHGTG, a massive computer was built to answer the Question. The computer
spent millions of years calculating, and arrived at the answer "42". The
problem, it said, was that the Question had never been formulated. The
computer then designed another computer to calculate the Question. After
millions of years of calculation, this computer was inadvertently destroyed.
The last remnants of the computer were only able to provide the question "What
is six times nine?"

Also, knowing the answer without knowing the question is Jeopardy!

------
fjordan
The number on HN lately seems to be 300,000.

------
faxilux
Fascinating read. He did say what the question was though: "What is six times
nine?"

[http://www.urbandictionary.com/define.php?term=6%20times%209...](http://www.urbandictionary.com/define.php?term=6%20times%209&defid=1303817)

~~~
Cushman
But note that that isn't the "real" question, just the incorrect result of the
Earth experiment.

------
X4
Wow all these numbers put me into an endorphine rush, I love these kind of
posts!! Keep them coming, it's no as theoretical as you may expect, it's
applications are endless.

    
    
        42, (Endo-)Fullerenes, the Omega Particle.
    

Do you remember the Star-Trek series that was about the Omega Particle? Isn't
it crazy that they were right?!

They actually exist. <https://en.wikipedia.org/wiki/Fullerene>
<https://www.youtube.com/watch?v=454uu96gFzU>

------
wfn
Good stuff.

Also,

    
    
        The picture of Klein’s quartic curve was made by Greg Egan, and you should also check out his page on Klein’s quartic curve.
    

For anyone curious, Greg Egan writes interesting hard scifi. A particularly
interesting and hardcore piece of scifi which rests on a significant pile of
graph theory et al. is his novel "Schild's Ladder." [1] (one of these days,
one of these days I am bound to attempt to finish it..)

[1] <http://en.wikipedia.org/wiki/Schild%27s_Ladder>

~~~
chii
wow, that schild's latter book sounds very interesting. Is there any more
similar kind of books like it (that deals with hardcore scifi themes)?

~~~
wfn
I'd ditto the question ;)

Semi-recent thread with some interesting-looking suggestions, not sure of
'hard' scifi label though:
[http://www.reddit.com/r/printSF/comments/1eyt3b/is_there_any...](http://www.reddit.com/r/printSF/comments/1eyt3b/is_there_any_sf_book_that_gets_orbital_mechanics/)

I'd recommend other books by Greg Egan, though. _Permutation City_
(<http://en.wikipedia.org/wiki/Permutation_City>) is particularly interesting
and makes some very interesting conjectures dealing with computation,
cognition, 'quantum ontology', etc. Character development is somewhat poor,
but eh! (there's also a FAQ on the author's website:
[http://gregegan.customer.netspace.net.au/PERMUTATION/FAQ/FAQ...](http://gregegan.customer.netspace.net.au/PERMUTATION/FAQ/FAQ.html))

------
geraldalewis
I'm not a math guy, but I was thinking about a number series the other day,
and 42 popped up. Do the numbers 1,806; 3,263,442; and/or 10,650,056,950,806
happen to have any significance as well?

~~~
scythe
That sequence is called "Sylvester's sequence":

<http://oeis.org/A000058>

The Online Encyclopedia of Integer Sequences is one of the coolest things on
the net.

~~~
geraldalewis
Thanks! Interesting that mine's off by one...

------
kirubakaran
The explanation that I liked the most was:

42

For-tea-two

Tea for two

~~~
claudius
I was never quite sure whether the number (42) or the decimal representation
thereof (4*10 + 2) was relevant. Your interpretation would tend to the latter…

~~~
tripzilch
I believe I read this in _The Salmon of Doubt_ , where Douglas Adams explained
he pretty much chose it arbitrarily. "42 will do", were his words, IIRC.

~~~
roryokane
I second that: I definitely remember reading something in which Douglas Adams
explained that he chose 42 arbitrarily. And I think he was surprised at and
amused with everyone’s theories of the significance of the number.

~~~
EGreg
What if it turns out that 42 really is the answer? :)

~~~
cfontes
Then "The Simpsons" would be right about the one true religion being a mix of
an amazon tribe belief and Mormons... and we are all going to hell...

------
bjoe_lewis
Is this guy a, genius?

~~~
coherentpony
Every number has special properties :)

Edit: In fact, I'd be astounded to encounter a number that did not exhibit any
special properties. Until, of course, one makes "having no special properties"
a special property. In that case, I would no longer be astounded.

~~~
quarterto
We proceed by induction. Clearly _n_ =1 is special, as it divides every
integer. Assume _k_ is special. If _k_ +1 is not special, then it is special,
as it is the first non-special number to come after a special number. This is
a contradiction; then _k_ +1 is special. ■

~~~
devgutt
Can you categorize the next non-special number in the same way? Now _k+1_ is
no longer non-special, but the reason why it is special still exists, so you
can't use it a second time.

~~~
coherentpony
I think it was meant to be in jest.

------
Natsu
This article is making me hungry for mathematically perfect hyper donuts.

------
vph
See the Strong Law of Small Numbers, of which 42 is one.

------
dnautics
it's also the Jackie Robinson number

------
maeon3
42 is the age after which women can not be expected (without the help of 21st
century technology) to produce children.

And thus is exposed the meaning of the life the universe, and everything:
"eat, stay alive, and produce more units that do the same". It is not your
responsibility to decide what the meaning of life is, it is the universe's and
physics responsibility to decide which loops are best at creating more
eaters/stay-alivers/reproducers.

