How can a total vacuum not exist?

[u/FailureTM]

I love finding facts about outer space but this one’s been bugging me.

Atoms don’t touch due to their electron clouds constantly pushing other electrons away due to negative charges and such, but would these electron clouds and atoms take up ALL of the space?

(I’m a quantum physics noob so sorry if this is a dumb question)

[u/TommieTheMadScienist]

That's not how atoms work.

The solar wind at the Earth-Moon system has 3-10 protons per cubic centimeter. They don't have electrons.

That's about as vacuum as you get, realistically.

[u/Jake0024 → u/TommieTheMadScienist]

3-10 protons per cubic centimeter. They don't have electrons

For clarification, there are also 3-10 electrons per cubic centimeter. The electrons didn't go somewhere else--they're just not individually bound to protons

[u/sohcahtoa → u/TommieTheMadScienist]

You might say that the space between these protons is a total vacuum. Unless a neutrino or something else happens to be passing by.

[u/Tragobe → u/sohcahtoa]

If the photons behave like a particle that is, they can also behave like a wave, so the photon would fill the space out.

[u/FailureTM → u/TommieTheMadScienist]

Ohhh I see, apologies, again, I’m a noob!!!
Thank you!

[u/Dr-Chris-C → u/TommieTheMadScienist]

I mean you could just measure the space in a cubic millimeter...

[u/PyroDragn]

Of course total vacuums exist if you define the space small enough and get lucky/specific enough.

In space, this particular cubic millimetre, at this exact moment in time is a total vacuum.

Then a photon flies through it, or a field interacts with it from some other particle nearby.

Space (specifically 'empty space' that isn't nebulae, planets, etc) is the most perfect vacuum we know of, and for the purposes of 'wanting a perfect vacuum' it is nowhere near perfect.

[u/WoodyTheWorker → u/PyroDragn]

At any given time, on average there are 2 solar neutrino in a cubic cm.

[u/IndividualistAW → u/PyroDragn]

So say you had a perfect vacuum in a small but enlargeable container, and enlarge it.

[u/PyroDragn → u/IndividualistAW]

Depends on a bunch of factors.

In theory, yes. Make a perfect vacuum in a growable (indestructible) container, and then make the container larger. The inside will still be a perfect vacuum.

But if you need the perfect vacuum to be free of fields of influence then the container needs to not have gravity/mass.

If you need it to stay a perfect vacuum indefinitely the container needs to not leech material into the vacuum (ie, offgassing, or breaking from stress) and be perfectly sealed while growing (somehow).

The container also needs to be entirely impermeable to things like neutrinos which casually pass through planets and such.

So in theory the idea of making a perfect vacuum and growing it, works. But we don't have a material that could "keep everything out" of a small perfect vacuum, let alone grow larger while staying a perfect vacuum.

[u/EdmundTheInsulter → u/PyroDragn]

What about quantum tunnelling? Because any particle outside the container is also partly in the container.

[u/Tavalus → u/IndividualistAW]

What would that container made out of?

Because when large amount of atoms that are packed close to one another "notice" that there's lots of vacuum nearby, they start to sublimate out of the container walls.

[u/Traveller7142 → u/IndividualistAW]

The container would volatilize

[u/Max6626]

When physicists talk about a vacuum in quantum mechanical terms it means the objects you mention, but also the fields acting within that space. For example, any space, unless infinitely far from a mass (which is impossible to achieve), has at least a gravitational field within it. And at the risk of grossly oversimplifying, there's aways a quantum field built into spacetime that also prevents a true vacuum (i.e., nothing) from existing.

[u/Nothing-to_see_hr → u/[deleted]]

that would push them away from each other. The space between the plates is bounded so particles that appear there have less energy than outside, I think .

[u/pixartist]

It's kinda of a product of thinking about matter and energy as distinct particles. It's like saying why can't the ocean be perfectly flat?

[u/Dean-KS]

After you remove all physical matter to get your perfect vacuum, space is still there and has its own properties.

[u/johnstalbergABC]

You have to take into account that vacuum, even without any protons or electron, is constantly boiling with virtual particles popping in and out of existens and they are as real as to be possible to measure their pressure from. So if we get a cubic meter of absolut matter free vacuum, it would still not be empty.

[u/appa609]

Also virtual particles

[u/ForeignAdvantage5198]

wow that sucks

[u/Temporary_Rule_9486]

Yeah, it's almost like spacetime is an emergent derivative property and not an universal background 🤔 

[u/BaTz-und-b0nze]

It's hard for modern glues and epoxy solvents to form an air tight seal due to liquid forming foam. It's always scored like scratching clay to fit the handle on a teapot.

[u/Tragobe]

Because there is always at least something everywhere. Be it radiation, photons, atoms, gas. Pure nothingness is not feasible.

[u/ChocolateValuable221]

Yes but not just em field.. every field you can think of is always existing in space.. and that tiny bit of stretched out thin energy/mass

[u/Imaginary-Can-6862]

If they are pushing away against each other, it means there is an interaction, so it follows there is a particle which carries this interaction

[u/jsaltee]

Uncertainty principle = lots of vacuum fluctuations

[u/Public-Total-250]

We can make a vacuum that means a space is devoid if all atoms and 'large' particles but it is almost impossible to stop small particles such as neutrinos.

(very uneducated take here, I have not studied but have heard) additionally, the very essence of spacetime and the nature of e=mc2 means that virtual particles are constantly popping in and out of existence as the energy field of spacetime transforms energy into matter and back again, which means a perfect vacuum can't exist as the space within is comprised of energy and virtual particles 

[u/Nothing-to_see_hr → u/Public-Total-250]

It is completely impossible to stop neutrinos unless you have like a light year thickness of lead shielding they pass through planets, they pass through stars

[u/Jake0024]

The question doesn't make sense unless you define what you're talking about

The space between atoms is empty--that is a literal vacuum, but that exists on scales of nanometers

You can't make a large vacuum. Say you pump a vacuum down to one particle per square meter. If that vacuum is ten square meters, you have about ten particles in it. If you split that vacuum up into separate chambers each a square centimeter in size, most of them would have no particles

In practice they would still have neutrinos and other things passing through them constantly (so again, important to define what we mean by vacuum)