Live data from Hacker News

We are not mostly empty space

medium.com

81–90 of 106 posts

Re: We are not mostly empty space

#81
post #11

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.

This comment made my day, thanks!

Re: We are not mostly empty space

#82
post #18

Earlier quoted context omitted.

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…

Right ... except that if I want to put more electrons in the same space I'm going to have to confine them more tightly. That prediction works.

An oxygen tank where you can safely add more oxygen by increasing the pressure is not considered full. The percentage of how empty a container is can be considered 1 -(amount of stuff in it) / (maximum stuff possible).

Re: We are not mostly empty space

#83
Excellent explanation. My question after this is, at a macro level,how much of space is actual pure space. Pardon the childish question but how exactly would one measure space (nothing exists at this point) without introducing something that might be displaced by the measurement,or how can one be sure space isn't made up of lower energy qanta that are displaced by higher energy particles,much like how solids displace gases and liquids?

Re: We are not mostly empty space

#84

Is 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 an…

> Electron is always a point, no matter what wave function it has. Therefore, from this perspective space is all empty.

That depends on what interpretation you're going with. Even with that caveat, I'd be surprised if most physicists would agree with that statement. Electrons are in fact described by the wave function. It's not that the wave function tells us where the electron is, but that the best way of describing the reality of the electron is through its wave function. How and why measurements seem to cause that wave function to collapse to a definite location is different depending on your interpretation of QM.

Re: We are not mostly empty space

#85
post #46

Earlier 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

Yeah, they're probability distributions, not fields. So electrons, protons and neutrons are still tiny, even though their positions are uncertain. And so atoms are still mostly empty space.

This is what I took from the article as well. Though, it's important to note that the 'billiard ball' particle model is just a model also.

On a related note, as a physics grad, I've been looking into growing evidence that shows consciousness affecting what we observe (i.e. wave-particle duality in this case).

Have you seen Steven Greer's latest film (CE5)?

Re: We are not mostly empty space

#86
post #82

Earlier quoted context omitted.

Right ... except that if I want to put more electrons in the same space I'm going to have to confine them more tightly. That prediction works.

An oxygen tank where you can safely add more oxygen by increasing the pressure is not considered full. The percentage of how empty a container is can be considered 1 -(amount of stuff in it) / (maximum stuff possible).

I think possibly you've defined "full" two different ways. Is it maximum safe pressure or maximum stuff possible?

Re: We are not mostly empty space

#87
post #46

Earlier 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

Yeah, they're probability distributions, not fields. So electrons, protons and neutrons are still tiny, even though their positions are uncertain. And so atoms are still mostly empty space.

Rather than thinking of space as empty vs non-empty, it might be better to think of space as a relationship between things.

I think you make less commitments of space this way.

Re: We are not mostly empty space

#88
post #46

Earlier 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

Yeah, they're probability distributions, not fields. So electrons, protons and neutrons are still tiny, even though their positions are uncertain. And so atoms are still mostly empty space.

“Empty space” is a concept from our scale that becomes absurd at small scale

Re: We are not mostly empty space

#89
post #82

Earlier quoted context omitted.

An oxygen tank where you can safely add more oxygen by increasing the pressure is not considered full. The percentage of how empty a container is can be considered 1 -(amount of stuff in it) / (maximum stuff possible).

I think possibly you've defined "full" two different ways. Is it maximum safe pressure or maximum stuff possible?

I don’t see the contradiction, Space unlike a gas tank is not going to fail.

Re: We are not mostly empty space

#90
post #11

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.

You can’t trust atoms. They make up everything.
Post reply on HN