Talk:Atom

uncut or uncuttable (indivisible)?

a means not and tomos means cutting. atom is typically translated with indivisible. I'll change it. AxelBoldt

I removed "even smaller particles which appear in nuclear reactions. The smaller particles (electrons, protons and neutrons) can be observed in many non-nuclear reactions; electrons are flying at your computer monitor and protons are swimming around in water and determine the PH. AxelBoldt

I'm picking nits here, but the proton example is not very good. While it is convenient to think of H⁺(aq) as a free proton that "swims" through the water, in reality it just isn't so. The proton is actually always surrounded by a coordination sphere of water molecules, with which it shares electrons (and is essentially covalently bonded). Sometimes this is represented as the formation of a hydronium ion (H₃O⁺), but even this is a simplification. In reality the extra proton is constantly interacting with multiple surrounding water molecules (and is likely exhanging places with hydrogen atoms in those molecules). Matt Stoker

I love etymology but I'm not sure that all encyclopedia users share my enthusiasm. Wouldn't it be better to relegate it to a sub-heading at the end? Unless, of course, the etymology actually has some bearing on the topic. What do the panel think? -- Heron

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How large is the estimated number of atoms in the universe?

Well, according to this definition (http://www.googol.com) of the term "googol", the number of particles in the Universe is estimated to be between 10^120 and 10^130. Since an atom is made up of particles, that means the number of "atoms" in the universe is considerably smaller than that. Under a googol, perhaps?

Currently, the best information we have suggests that the universe, and the number of particles within it, is infinite. The links above probably talk about the observable universe, which consists of those parts of the universe which are close enough so that the light emitted by them has already reached us. AxelBoldt 23:45 Oct 12, 2002 (UTC)

If I remember correctly there are/were some theories saying that the universe is finite, although very large. I would be interested in knowing more about this. Who thinks what why? Any pointers?

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Someone asked, in the following comment that I removed from the article:

(what was the name of the model Aristotle used? where atoms where like small pebble with different shapes)

I think the questioner was thinking of Democritus, the atomist, and not Aristotle, who denied atomism. Democritus believed that the properties of atoms were determined by their shapes. I put in a link to Democritus, but I think Democritus' idea should be discussed in this article. --Heron