71–80 of 106 posts
What does that mean? Most interpretations of quantum mechanics consider the wave function to be an abstraction to model the system, not something that is actually tangible. Even in theories that consider it real (e.g. De Broglie-Bohm) it acts as some sort of field, not something that actually occupies space.
> But until such an interaction occurs, the electron has been acting like a wave all along. What does that mean? Most interpretations of quantum mechanics consider the wave function to be an abstraction to model the system, not something that is actually tangible. Even in theories that consider it real (e.g. De Broglie-Bohm) it acts as some sort of field, not something that actually occupies space.
How often do objects interact with our bodies when passing through us? Neutrinos, very rarely. The atoms of an aluminum bat, very commonly. Light? It depends. Something being "empty" or "full" all depends on spatial and energetic scale.
Yeah, the fact that neutrinos pass through us largely validates the notion that we are in fact mostly empty space.
Empty space, by definition, is space that can be filled by something. So how closely can atoms pack together? A neutron star has a density of 10^17 kg/m^3, whereas the typical human being is about 10^3 kg/m^3. I could fit the matter of trillions more human beings in the same space I'm taking up now. So yeah, I think there's some empty space in me.
Is it? I'd say empty space is empty space whether it can be filled or not.
If the universe was just 2 plates N meters apart that was impossible to move any closer (e.g. because of opposite forces, like with magnets which work fine in a vacuum), the space between them would still make sense to call empty...
If "empty" means "I can put electrons in there", then it takes more binding energy to pack more electrons into the same space. If you want to pack more electrons in, you have to squeeze harder.
Example: you can confine an electron to a tiny part of an atom (electrons in inner shells of heavy atoms, for example) but those electrons are very tightly bound (held in by very high ionization energies).
Or the "emptiness" of an atom could be measured using neutral particles, which don't interact with the electrons at all and sail right through as if the electrons were empty space.
For what it's worth this is normal sophomore physics. There's no way to just dismiss it. But there's also no way to claim it's less than a hundred years old.
> Atoms exist on extremely tiny scales, just 1 ångström across... I may be misinterpreting, but it sounds like he's saying all atoms are 1 ångström in diameter.
“Empty space” is a completely relative notion. If I have a heavy steel safe which I do not have the key for, whether there is an empty space inside it is irrelevant, and the space occupied by the safe cannot be seen as being (partially) empty in any practical sense.
Earlier quoted context omitted.
From what I understand, the idea of "empty" no longer makes sense at that level. All you have are fields. There, everything is made out of fields and fields are everywhere. There is therefore no "empty" really anywhere, including inside yourself.
Physics is all based on predictions not arbitrary definitions. To suggest something is filling space you must be able to hit it with something else. This talk of empty space, comes from actual experiments. Shoot a neutral particle through that cloud and you generally find it really was empty. Wave particle duality doesn’t mean a particle is in every location, just that it could be in every location. After detection y…
Earlier quoted context omitted.
But visible light can't get through us at all. Does that prove that we aren't empty space? The whole point is that this criterion is incredibly ambiguous.
> But visible light can't get through us at all. visible light definitely gets through me when I put my hand in front of a bright light source
Empty space, by definition, is space that can be filled by something. So how closely can atoms pack together? A neutron star has a density of 10^17 kg/m^3, whereas the typical human being is about 10^3 kg/m^3. I could fit the matter of trillions more human beings in the same space I'm taking up now. So yeah, I think there's some empty space in me.
> Empty space, by definition, is space that can be filled by something. Is it? I'd say empty space is empty space whether it can be filled or not. If the universe was just 2 plates N meters apart that was impossible to move any closer (e.g. because of opposite forces, like with magnets which work fine in a vacuum), the space between them would still make sense to call empty...
Though technically correct when sticking to matter, it feels so wrong because of how it encourages inapplicable intuitions from the macroscopic world.
"We are mostly empty space" is used as trivia, with an implicit exclamation mark suggesting it is astonishing and significant, but it is intentionally incomplete and lacks context - the whole picture shows something far more substantial that has nothing to do with our macroscopic intuitions.