Earlier quoted context omitted.
Call me old fashion but I don't consider anything inside the perimeter of an atom as empty space.
Then how do black holes and neutron stars work?
The fields that fill the space are squished?
We are not mostly empty space
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Re: We are not mostly empty space
#22Earlier quoted context omitted.
So the author is saying fields are already filling things up, right? To compare this to the "we can pack them atoms tighter" model seems to be confusing the author's model with another, separate mental model, one in which we can fill up more. But the author's model says we're full. Full of this field stuff. Not so? IANAS
You’re not filled with fields or those fields would block neutrinos. Instead we can shoot them though the earth and detect them just fine on the other side. Fields represent possible locations, not actual locations.
For anything that responds to the electromagnetic force, you're filled with fields. For something that responds only to the weak force, you're almost entirely empty space.
Re: We are not mostly empty space
#23Earlier quoted context omitted.
You’re not filled with fields or those fields would block neutrinos. Instead we can shoot them though the earth and detect them just fine on the other side. Fields represent possible locations, not actual locations.
For anything that responds to the electromagnetic force, you're filled with fields. For something that responds only to the weak force, you're almost entirely empty space.
If that’s how you want to look at it, everything responds to gravity. But, that’s not what people mean when they say space is filled.
Re: We are not mostly empty space
#24Speak for yourself. I've been feeling pretty empty lately.
Re: We are not mostly empty space
#25How 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.
Re: We are not mostly empty space
#26Earlier quoted context omitted.
Call me old fashion but I don't consider anything inside the perimeter of an atom as empty space.
Atoms don’t have a “perimeter”. That’s the point. Atoms are mostly "empty space" in the same way that the gap between a maglev train and its track is empty space (ignoring the air).
Why the downvotes? That reply might have been ELI5-level, but I am a physicist.
Atoms are fuzzy things without a hard interface boundary. At that scale it doesn't really make sense to say they have a "perimeter" at all. The distance at which they repel each other is different from the distance at which they cling together in a hydrogen bond, which is different from the distance between covalently bonded atoms, etc. The electrons themselves roam all over the place, including far outside whatever bond distance you might choose as the size of an atom. In short, there isn't a perimeter which defines "inside" and "outside" of the atom.
The "empty space" thing is a bit of a poor analogy anyway. It comes from chemical experiments which showed that the repulsive cross section of an atom when pummeled with zero-charge particles is orders of magnitude smaller than the electric cross section. These are different forces though (strong vs electromagnetic), so it's a bit apples-to-oranges to begin with.
Re: We are not mostly empty space
#27Earlier quoted context omitted.
You’re not filled with fields or those fields would block neutrinos. Instead we can shoot them though the earth and detect them just fine on the other side. Fields represent possible locations, not actual locations.
For anything that responds to the electromagnetic force, you're filled with fields. For something that responds only to the weak force, you're almost entirely empty space.
In the English-language usage I grew up with, 'occupied' means that there is something there, while 'filled' means occupied to the point where nothing more can be added. The former does not imply the latter.
In this usage, space itself (the 'empty' space of the article's title) is implicitly not something.
This usage may seem to be an accidental issue of language, resulting from an incomplete understanding of physics, but a lot of metaphysics seems to reach the point of hanging on such definitions. One may, of course, agree with both of the points of view expressed in this paragraph.
Re: We are not mostly empty space
#28Is it just me who found the technical description and analogy here lacking?
There's nothing that suggests electrons are a cloud. Yes, a "cloud" defines the probability where they can be found, but electron doesn't occupy the cloud.
Electron is always a point, no matter what wave function it has. Therefore, from this perspective space is all empty.
If you invoke path integrals and infinitely many things bubbling in and out of existence, space suddenly fills up. But the author doesn't even mention that.
If you want to understand this stuff, read up Feynman's descriptions & lectures on QED.
Downvote for this article (sorry).
Re: We are not mostly empty space
#29> Inside your body, you aren’t mostly empty space. You’re mostly a series of electron clouds, all bound together by the quantum rules that govern the entire Universe. So we are mostly electron clouds... and clouds by definition are mostly empty space.
But if this article is correct, then clouds are not, by definition, mostly empty space!
My point is that one cannot settle this sort of issue by invoking the definition of words. I am not sure what sort of fallacy the 'argument by dictionary definition' is, but it is definitely a fallacy (except possibly in lexicography.)
Re: We are not mostly empty space
#30How 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.