Is this actually physically correct? I was under the impression that "width of an electron" isn't something we have a good value for, if it's a meaningful quantity at all...
You're right. The electron is a point particle. It has no size (though, interestingly, it has angular momentum - i.e. it spins on itself. Go figure).
I guess the page is intended to render the distance between the proton and the electron rather than the size relationship between the two.
On the other hand, even that is somewhat dubious. Electrons aren't located in a single place, they can be anywhere within a certain area, according to their probability density function - including right in the middle of the proton, though the probability of that is low.
From that article, the ratio Rp to Re is about 83. But the more I look, the more answers I find. Scienceworld has 0.80+ fm for the proton, is silent on the electron. Comparing the following two (Physics Factbook), they could be about equal. "The electron is a point-like particle-that is, a particle with no measurable dimensions, at least within the limitations of present-day instrumentation. "
It's actually a limit of the model, not of the measuring device. The electron has angular momentum, but even if it were only as big as the smallest allowed size in quantum mechanics (Plank's constant), the speed of rotation would be faster than the speed of light. Since this is impossible, the model just defines the size of the electron as 0.
> at least within the limitations of present-day instrumentation
At least that gives a maximum size for the electron while it is interacting like a particle, though true, it is probably quite a bit smaller.
The fun thing to do, would be to draw the full s orbital, noting that the electron can interact with anything inside (and a bit outside) the full 11 mile radius sphere.
This coupled with the size of the largest stars is truly mind-boggling (much less the size of the universe or the size of a quark). It's amazing how we humans, as primitive as we are, can at least have an idea of the scale of the universe. All through pictures and ideas.
But there's a difference between being able to reason about the magnitude of a number theoretically, and actually visualizing such a distance in your mind, which I find incredibly hard to do.
11 miles radius at a resolution of one pixel's width. That's like visualizing an entire city, from close enough to distinguish cracks in the sidewalks.
Interesting, the diameter of the Earth is about 12,000 km. The distance to the Sun is about 150 million km. The Hydrogen atom is much "larger", in comparision.
If you really want a mindf-ck, check Avogadro's number (6.022 * 10^23), the number of atoms in 12 grams of C.
Edit: I might add that I learned the above from a chemistry course book. More sense of wonder than when I read about the Orion project; almost as when I learned where atoms heavier than Helium comes from.
