# Unlikely things in an infinite universe

**URL:** https://boards.straightdope.com/t/unlikely-things-in-an-infinite-universe/308535
**Category:** Factual Questions
**Created:** [June 16, 2005, 1:32pm UTC](https://boards.straightdope.com/t/unlikely-things-in-an-infinite-universe/308535 "2005-06-16T13:32:58Z")
**Posts on this page:** 20
**Page:** 1

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### Author: ![FlippyFly](https://avatars.discourse-cdn.com/v4/letter/f/e95f7d/32.png) [@FlippyFly](https://boards.straightdope.com/u/FlippyFly)
#### Post date: [June 16, 2005, 1:32pm UTC](https://boards.straightdope.com/t/unlikely-things-in-an-infinite-universe/308535/1 "2005-06-16T13:32:58Z")

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I was reading Hitchhiker’s guide yesterday, and they had an interesting section in there in which, to paraphrase, the author said this:

Virtually nothing is manufactured anymore, because in an infinite universe, most anything anyone wants grows naturally somewhere.

This got me thinking. The logic seems solid enough… as improbable as anything seems, if there is a non-zero chance of it occurring, than in an infinite universe, it will occur… so do VW bugs grow on some planet somewhere?

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### Author: ![Sunspace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sunspace/32/1250_2.png) [@Sunspace](https://boards.straightdope.com/u/Sunspace)
#### Post date: [June 16, 2005, 1:37pm UTC](https://boards.straightdope.com/t/unlikely-things-in-an-infinite-universe/308535/2 "2005-06-16T13:37:54Z")

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But how do we know that the universe is infinite? Most stuff I’ve read recently seems to give it a definite size.

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### Author: ![KarlGauss](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/karlgauss/32/3713_2.png) [@KarlGauss](https://boards.straightdope.com/u/KarlGauss)
#### Post date: [June 16, 2005, 1:44pm UTC](https://boards.straightdope.com/t/unlikely-things-in-an-infinite-universe/308535/3 "2005-06-16T13:44:17Z")

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> [@FlippyFly](#):
>
> in an infinite universe, do VW bugs grow on some planet somewhere?

The answer seems to be yes (so long as the occurence is physicallty possible). See the last three paragraphs before the list of references [here](http://math.ucr.edu/home/baez/end.html).

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### Author: ![Revtim](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/revtim/32/1042_2.png) [@Revtim](https://boards.straightdope.com/u/Revtim)
#### Post date: [June 16, 2005, 2:21pm UTC](https://boards.straightdope.com/t/unlikely-things-in-an-infinite-universe/308535/4 "2005-06-16T14:21:58Z")

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This is probability a question that I always forget the answer to:

If you flip a coin over and over literally forever, is it IMPOSSIBLE that heads will NEVER come up, or just unlikely to the extreme?

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### Author: ![ultrafilter](https://avatars.discourse-cdn.com/v4/letter/u/3d9bf3/32.png) [@ultrafilter](https://boards.straightdope.com/u/ultrafilter)
#### Post date: [June 16, 2005, 2:25pm UTC](https://boards.straightdope.com/t/unlikely-things-in-an-infinite-universe/308535/5 "2005-06-16T14:25:27Z")

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> [@Revtim](#):
>
> If you flip a coin over and over literally forever, is it IMPOSSIBLE that heads will NEVER come up, or just unlikely to the extreme?

It’s not impossible, but the probability is 0. Keep in mind, though, that the probability of any single sequence of flips in this scenario is 0.

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### Author: ![Revtim](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/revtim/32/1042_2.png) [@Revtim](https://boards.straightdope.com/u/Revtim)
#### Post date: [June 16, 2005, 2:27pm UTC](https://boards.straightdope.com/t/unlikely-things-in-an-infinite-universe/308535/6 "2005-06-16T14:27:36Z")

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Is the probability actually 0, or does it _approach_ zero? (It’s been long time since calc, which I never learned well to being with)

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### Author: ![ultrafilter](https://avatars.discourse-cdn.com/v4/letter/u/3d9bf3/32.png) [@ultrafilter](https://boards.straightdope.com/u/ultrafilter)
#### Post date: [June 16, 2005, 2:29pm UTC](https://boards.straightdope.com/t/unlikely-things-in-an-infinite-universe/308535/7 "2005-06-16T14:29:23Z")

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It’s actually 0.

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### Author: ![micco](https://avatars.discourse-cdn.com/v4/letter/m/5f8ce5/32.png) [@micco](https://boards.straightdope.com/u/micco)
#### Post date: [June 16, 2005, 2:42pm UTC](https://boards.straightdope.com/t/unlikely-things-in-an-infinite-universe/308535/8 "2005-06-16T14:42:24Z")

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> [@FlippyFly](#):
>
> as improbable as anything seems, if there is a non-zero chance of it occurring, than in an infinite universe, it will occur… so do VW bugs grow on some planet somewhere?

Yes, but the statistics also say that it will take an infinite number of explorers an infinite amount of time to find them, so you’re better off just building what you need.

In this particular case, the problem is compounded by the fact that VW Bugs are a legume (at least on all the known worlds where they’ve been found). The only time they get spotted by satellite is when the natives use their husks as yard art.

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### Author: ![dlack](https://avatars.discourse-cdn.com/v4/letter/d/b5ac83/32.png) [@dlack](https://boards.straightdope.com/u/dlack)
#### Post date: [June 16, 2005, 3:09pm UTC](https://boards.straightdope.com/t/unlikely-things-in-an-infinite-universe/308535/9 "2005-06-16T15:09:23Z")

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> [@Revtim](#):
>
> Is the probability actually 0, or does it _approach_ zero? (It’s been long time since calc, which I never learned well to being with)

If you flip it an infinite number of times the probability is actually zero.

However, you can’t, so it isn’t. You can approach an infinite number of times, so the probability will approach zero.

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### Author: ![Revtim](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/revtim/32/1042_2.png) [@Revtim](https://boards.straightdope.com/u/Revtim)
#### Post date: [June 16, 2005, 3:24pm UTC](https://boards.straightdope.com/t/unlikely-things-in-an-infinite-universe/308535/10 "2005-06-16T15:24:36Z")

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Nicely explained **dlack** and **ultrafilter** , thanks.

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### Author: ![Futile\_Gesture](https://avatars.discourse-cdn.com/v4/letter/f/f05b48/32.png) [@Futile\_Gesture](https://boards.straightdope.com/u/Futile_Gesture)
#### Post date: [June 16, 2005, 3:57pm UTC](https://boards.straightdope.com/t/unlikely-things-in-an-infinite-universe/308535/11 "2005-06-16T15:57:44Z")

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> [@FlippyFly](#):
>
> so do VW bugs grow on some planet somewhere?

In an infinite universe… yes.

But as has been pointed out, you’re infinitely unlikely to find that planet. Which is where Douglas Adam’s idea rather fails. And if you did find it, you’re likely to have to transport it an infinite distance back home. Which is further than any other VW has travelled before.

I suppose you might be able to narrow your chances a little if you’re not fussy about the colour.

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### Author: ![Thudlow\_Boink](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/thudlow_boink/32/320_2.png) [@Thudlow\_Boink](https://boards.straightdope.com/u/Thudlow_Boink)
#### Post date: [June 16, 2005, 4:02pm UTC](https://boards.straightdope.com/t/unlikely-things-in-an-infinite-universe/308535/12 "2005-06-16T16:02:30Z")

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> [@FlippyFly](#):
>
> so do VW bugs grow on some planet somewhere?

They don’t actually grow—they’re being assembled by an infinite number of monkeys with an infinite number of monkey wrenches, right next door to the monkeys that are typing Shakespeare.

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### Author: ![Revtim](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/revtim/32/1042_2.png) [@Revtim](https://boards.straightdope.com/u/Revtim)
#### Post date: [June 16, 2005, 4:03pm UTC](https://boards.straightdope.com/t/unlikely-things-in-an-infinite-universe/308535/13 "2005-06-16T16:03:57Z")

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An infinite universe can repeat the same finite forms infinitely, so an infinite universe may NOT necessarily contain VW bugs growing somewhere.

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### Author: ![Thudlow\_Boink](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/thudlow_boink/32/320_2.png) [@Thudlow\_Boink](https://boards.straightdope.com/u/Thudlow_Boink)
#### Post date: [June 16, 2005, 4:08pm UTC](https://boards.straightdope.com/t/unlikely-things-in-an-infinite-universe/308535/14 "2005-06-16T16:08:10Z")

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> [@FlippyFly](#):
>
> if there is a non-zero chance of it occurring, than in an infinite universe, it will occur… so do VW bugs grow on some planet somewhere?

This seems like a pretty big _if_. How would you know ahead of time whether there is a non-zeo chance of something occurring?

Note that in an infinite list of random real numbers, the probability of any particular real number (like 1 or pi) ever showing up is 0.

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### Author: ![Hoodoo\_Ulove](https://avatars.discourse-cdn.com/v4/letter/h/58956e/32.png) [@Hoodoo\_Ulove](https://boards.straightdope.com/u/Hoodoo_Ulove)
#### Post date: [June 16, 2005, 4:19pm UTC](https://boards.straightdope.com/t/unlikely-things-in-an-infinite-universe/308535/15 "2005-06-16T16:19:43Z")

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> [@Thudlow Boink](#):
>
> Note that in an infinite list of random real numbers, the probability of any particular real number (like 1 or pi) ever showing up is 0.

That’s why I like integers.

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### Author: ![Padeye](https://avatars.discourse-cdn.com/v4/letter/p/a9a28c/32.png) [@Padeye](https://boards.straightdope.com/u/Padeye)
#### Post date: [June 16, 2005, 4:31pm UTC](https://boards.straightdope.com/t/unlikely-things-in-an-infinite-universe/308535/16 "2005-06-16T16:31:10Z")

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I think the odds of VW bugs growing on some planet in an infinite universe is the same as flipping a quarter (Regular US Washington/Eagle quarter) an infinite number of times and having it ever land banana side up. There may be an infinite number of chances but it isn’t going to happen unless there is a mechanism for it to happen within the laws of physics.

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### Author: ![CurtC](https://avatars.discourse-cdn.com/v4/letter/c/ce73a5/32.png) [@CurtC](https://boards.straightdope.com/u/CurtC)
#### Post date: [June 16, 2005, 5:35pm UTC](https://boards.straightdope.com/t/unlikely-things-in-an-infinite-universe/308535/17 "2005-06-16T17:35:57Z")

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So, in an infinite universe, assuming that all parts of it have random atoms moving around through the interstellar space, wouldn’t there be a fully-assembled 747 somewhere out there that happened randomly?

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### Author: ![Padeye](https://avatars.discourse-cdn.com/v4/letter/p/a9a28c/32.png) [@Padeye](https://boards.straightdope.com/u/Padeye)
#### Post date: [June 16, 2005, 5:53pm UTC](https://boards.straightdope.com/t/unlikely-things-in-an-infinite-universe/308535/18 "2005-06-16T17:53:53Z")

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> [@CurtC](#):
>
> So, in an infinite universe, assuming that all parts of it have random atoms moving around through the interstellar space, wouldn’t there be a fully-assembled 747 somewhere out there that happened randomly?

it takes more than a random collection of atoms to make a 747. Even if all the correct atoms were in one region what would bring them together? The mass of a 747 doesn’t have enough gravity to do that and if it did it wouldn’t make a 747 shape. Notice any cube shaped planets? Even if all the atoms bumped together in the right places there would be nothing to hold them together. I still think that an infinite universe does not mean that every object imaginable must exist in it. We’d just end up with a lot of stuff similar to what we see in our on region of our galaxy with extremely small odds of finding a jupiter size planet with rings made out of pipe cleaners.

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### Author: ![Hoodoo\_Ulove](https://avatars.discourse-cdn.com/v4/letter/h/58956e/32.png) [@Hoodoo\_Ulove](https://boards.straightdope.com/u/Hoodoo_Ulove)
#### Post date: [June 16, 2005, 6:00pm UTC](https://boards.straightdope.com/t/unlikely-things-in-an-infinite-universe/308535/19 "2005-06-16T18:00:00Z")

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It should be pointed out that everyting in the universe, including VWs and 747s is the result of random activity at the quantum level. No?

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### Author: ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)
#### Post date: [June 16, 2005, 6:03pm UTC](https://boards.straightdope.com/t/unlikely-things-in-an-infinite-universe/308535/20 "2005-06-16T18:03:43Z")

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> [@](#):
>
> it takes more than a random collection of atoms to make a 747.

No, it could happen. Start with a nebula which happens to contain some aluminum, magnesium, iron, titanium, and whatever other elements you need for a 747. That’s not too bad; all of the aluminum etc. which we use to make 747s was in a nebula at some point. Now, have a gentle collision between two atoms, which results in them sticking together. OK, that happens all the time in nebulae. And now, and here’s the kicker, repeat that same process about 10[sup]32[/sup] times, with each one just happening to involve the exact sort of atom you need, at the exact right spot on the growing atom-clump. The end result? A 747. Improbable in the extreme, certainly, but not impossible.

[Next page](https://boards.straightdope.com/t/unlikely-things-in-an-infinite-universe/308535.md?page=2)
