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Comment by archgoon | Hacker News Reader

Yes, the Rutherford gold foil experiment was basically where we went from "It's a positive sphere with some electrons stuck in it" to "Oh, looks like there's a super dense positive center and the rest is mostly empty space".

The author of the article is welcome to compute the mass density of the atom's periphery to the nucleus, and return to speculating whether it's fair to argue that the atom is mostly empty space or not.

For myself, I'm happy to refer to ethereal probabalistic cobwebs as "mostly" empty space.

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I was actually pretty interested to see the diagram in the article showing how delocalized the hydrogen nuclei are in NH3. I do have a science degree, and I’ve seen plenty of electron probability density renderings, but the extent to which protons “spread out” was surprising to me.

Possibly even emptier! The other one has at least some particles in it.

The probability thing is misleading though, it's really all about energy. Matter is just highly concentrated energy and just because the nucleus happens to be much more concentrated energy, does that make the energy of the electron cloud non-existent?

As a thought experiment: If you have a peach, would you declare the fleshy part non-existent once the pit achieves a certain mass density?

Your thought experiment isn't the same scenario.

The actual scenario is this: "If you have a peach, would you declare the fleshy part non-existent if it had a certain probability of reallocating itself to a single spot once the pit achieves a certain mass density and if you touch it, there is only a small probability that you can even feel that the flesh is there?"

Electrons never reallocate themselves to a single spot. There's no evidence that collapse actually happens, that's just one weird interpretation (Copenhagen).

The entire electron cloud produces an electro-repulsive force that is very real. That is what you feel, there's no small probability about it. This idea that there's some small probability that you hand will go straight through the table is ridiculous.

When you touch a peach, some of your electrons/atoms actually do become part of the peach and vice-versa. If we somehow turned up the tunneling probability, your hand would not go through things, it would simply dissolve into things more readily.

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