I think the answer is somewhere in the region of a googol molecules (101 digits), but was wondering how much varience there is in different approximations. How about atoms? Protons/Neautrons/electrons? Quarks?
The reason I ask is that I’ve been asked by my project supervisor to write a program dealing with 2^2^m possibilities and he wants me to be able to deal with n=20. This gives a number with several thousand digits.
Paddle.
ps. Sorry if this has been dealt with, but I searched unsuccessfully.
This page gives some some numbers. There aren’t a googol of anything in the universe. Even the number of photons falls short by a factor of something like 10[sup]12[/sup]. That’s 12 orders of magnitude, folks!
The numbers on that page agree with what I’ve heard, but I think the answer man is a little confused. “No, don’t keep arguing”, and then he attaches something that explains why the questioner is right! And then he titles the column “Lots and Lots of Atoms in the Universe” when the point of the article is that it’s less than a googol.
Incidentally, the number of molecules in the universe is equal to the number of protons, or the number of atoms, to within an order of magnitude.
This strikes me as more than a little bit odd. As far as anyone knows the universe is infinite in space. How do you go about calculating how much matter is present in an infinite volume?
For example, lets say for every cubic(?) lightyear of space you have one atom. Infinite space means that even with only 1 atom per lightyear^3 you still have infinite atoms.
The case that your cite seems to make (correct me if I’m wrong, which I just might be) is that going by the big bang theory the universe started at a single point and since it is just expanding, the mass remains the same. The problem with that is, how do we have any idea how much mass was present in the big bang?
I may be misreading, but that’s not what the cite says at all. He emphasizes the fact that he’s talking about the observable universe, the current proper volume of a light-cone starting at the Big Bang with us at center (in our frame). Using that and the local proper number density of photons, you can get the total number of photons in the observable universe.
As for the mass, you use cosmological observations to get Omega[sub]M[/sub] and H[sub]0[/sub], which gives you the proper mass density, which you can use along with the proper volume to get the total mass.
Scientific American had an article on parallel universes last year (Feb or March 2003, I think) that brought this up. There are a large, but finite, number of Planck volumes in the observable universe, so therefore there are a finite number of possible arrangements they can all be in (somewhere in the neighborhood of 10^10^100). Given an infinite universe, this means that there must be other volumes of space with exactly the same arrangement as our observable universe. Same milky way, same sun, same earth, same people, same SDMB.
We’ve been through this over and over in previous threads. An infinite universe in no way shape or form implies that all arrangements must occur. The power set of a set is vastly larger than the set. Vastly larger. You can’t put them into one-to-one correspondence so most combinations will never occur. And by “most” I mean as close to nearly all as you could probably think of.
