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On the (Small) Number of Atoms in the Universe

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Re: On the (Small) Number of Atoms in the Universe

#71

Post by gnodar »

levemi wrote: post #67
dsfuoi wrote: post #45

Earlier quoted context omitted.

It could be infinite.

If that is the case was the universe once finite and then went infinite during the early (big bang) expansion? I don't understand how something could have expanded if it was always infinite in size. I'm not even sure the concept of expansion even makes sense. What is infinite + 1? It's just infinite. It seems more like the expansion is a distribution of internal things.

I don't know the answer to your question, but I can imagine how something can expand if it's infinite. Imagine an infinitelylong rubber band in front of you. Now imagine grabbing it with two hands and pulling them away from each other, causing the rubber band to stretch. If you take a sharpie, and paint dots on a spot representing planets or whatever else, they will pull away from eachother as you stretch the rubber band.

Re: On the (Small) Number of Atoms in the Universe

#73

Post by yolesaber »

yk wrote: post #41
creshal wrote: post #26

Earlier quoted context omitted.

But electrons interact with each other, don't they? How'd that work?

The electron goes forward and backward in time and interacts with itself. (In quantum field theory you can replace a positron with an electron going backwards in time). Regrettably the theory does not work, since it would predict the same number of electrons and positrons in the universe.

The positrons might be hiding in the protons!

Re: On the (Small) Number of Atoms in the Universe

#74

Post by pcmonk »

Retric wrote: post #70
levemi wrote: post #67

Earlier quoted context omitted.

If that is the case was the universe once finite and then went infinite during the early (big bang) expansion? I don't understand how something could have expanded if it was always infinite in size. I'm not even sure the concept of expansion even makes sense. What is infinite + 1? It's just infinite. It seems more like the expansion is a distribution of internal things.

Math includes the idea of orders of infinity. There are infinite prime numbers, there are more positive integers, even more integers (positive and negative), even more rational numbers (A/B), and even more numbers (rational + irrational {e, Pi} etc)...

In what sense are there more rational numbers than prime numbers? They can be put into bijection with each other, so we generally think of them as being same infinity. There are more real nubmers, of course, by Cantor's diagonalization, so your basic point is true.

Re: On the (Small) Number of Atoms in the Universe

#75

Post by overcast »

evanpw wrote: post #62
overcast wrote: post #10

Earlier quoted context omitted.

Actually the Earth is nearly perfect, far more perfect than most any sphere with interact with in day to day life. The equatorial bulge is 20 miles or so, which is approximately .33% Technically an oblate spheroid, but barely.

There's a great Isaac Asimov essay on this topic: http://chem.tufts.edu/answersinscience/relativityofwrong.htm

Great find, thanks!

Re: On the (Small) Number of Atoms in the Universe

#76

Post by ChristianBundy »

tromp wrote: post #64
harryjo wrote: post #61

Earlier quoted context omitted.

I don't think anyone believes that Go is somehow more complex than the universe it is a subset of. The point is that enumerating all cases of Go is impossible and always will be, so more sophisticated analysis is required.

Indeed, enumerating all 208168199381979984699478633344862770286522453884530548425 639456820927419612738015378525648451698519643907259916015 628128546089888314427129715319317557736620397247064840935 positions in Go is impossible.

That's called "counting". Enumeration is iterative.

Re: On the (Small) Number of Atoms in the Universe

#77

Post by School-Cotton »

krastanov wrote: post #24
PaulHoule wrote: post #21

If you believe in the axiom of choice (I don't) then you can imagine a process which has more degrees of freedom in in than anything at all.

It is an axiom, it is not something that you believe in. You assume it and you prove stuff with it. You do not and you prove stuff without it. If you are really good, you show what theorems require it. You can believe or not in some physical reality to math (I happen to), and then the axioms do become somewhat more than just logic statements, but that is different.

> You can believe or not in some physical reality to math (I happen to)

I'm not so sure. Is there any evidence that the value of any physical quantity is an irrational number?

Math was originally inspired by physical reality, but I'm not sure it's so closely related that the concept of the Axiom of Choice being "true" even means anything.

Re: On the (Small) Number of Atoms in the Universe

#78

Post by chinathrow »

dsfuoi wrote: post #45
Retric wrote: post #43

Earlier quoted context omitted.

Don't conflate the "Observable Universe" with the actual Universe. We flat out don't know how big the actual Universe is. So, it could be 10^80, 10^800, or even A(10, 80)* Atoms. * https://en.wikipedia.org/wiki/Ackermann_function

It could be infinite.

It could be a simulation.

http://www.scientificamerican.com/article/are-we-living-in-a...

Re: On the (Small) Number of Atoms in the Universe

#79

Post by kagia »

If 12megapixels can produce 10 to the power 86696638 images, and we came up with a way of enumerating those images, could we then build a function that given anyone of those images return the index of that image within reasonable time with current hardware. ie. "you have just taken 3999999987493th image"?

Re: On the (Small) Number of Atoms in the Universe

#80

Post by chrismbarr »

kagia wrote: post #79

If 12megapixels can produce 10 to the power 86696638 images, and we came up with a way of enumerating those images, could we then build a function that given anyone of those images return the index of that image within reasonable time with current hardware. ie. "you have just taken 3999999987493th image"?

A friend of mine made a tool that did exactly this, but with Haikus instead. He had a dictionary of syllables, and then just iterated through the syllables (following the rules of a haiku). You can type in a haiku and find its index, or just iterate through the indices to see the (mostly nonsense) generated haikus.
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