# Absolute vacuum between atoms?

1. Dec 4, 2009

### Rishav1

Isn't the distance between two atoms where nothing exists, no atoms or subatomic particles, absolute vacuum?

a place where nothing exists??

I am not too educated in such physics, so please do explain what you say

2. Dec 4, 2009

### James Leighe

Turns out there is no such thing as 'absolute vacuum' between anything... There are things called 'virtual particles' that pervade all of space and you can see their effect in things like magnetism. Wiki virtual particles and vacuum if you want to know more.

3. Dec 4, 2009

### Tac-Tics

When you get down to that level, it's not even clear what you mean by "exists". Fundamental particles aren't balls. In fact, we don't know anything about what they ARE. We only know what they do.

Physics doesn't know the answers to the universe. We create little rules for ourselves and see if they work. In electromagnetism, we make up these little arrows at each point in space called a field. In our little model, the field permeates throughout all of space. Is the field "real"? Does it "exist"? It's not really productive to even ask those kinds of questions.

The same goes for atoms and fundamental particles. An atom or a proton, according to QM, is going to have a wave function that exists all throughout space. In most places, it is damn near zero. So between any two atoms, the "empty space" is filled with mathematical constructs we have invented. It's not clear that they exist at all. It's not clear our model is even accurate. All we know is that we can predict results of experiments with them.

4. Dec 4, 2009

### arunma

In addition to what others have said, I would just point out that between two atoms, you'll still have wavefunctions from atomic electrons. Some of those wavefunctions only die off as $$r^n e^{-r/a_0}$$, so you really can't even say that the wavefunction is approximately zero between atoms.

5. Dec 11, 2009

### Rishav1

so that means, ultimately we know nothing

6. Dec 11, 2009

### Astronuc

Staff Emeritus
No, that's not what the statements mean.

We can describe the nature of matter and energy and predict behavior in many circumstances quite well. What applies on the macroscopic level, in terms of visualizing or conceptualizing, does not apply to the atomic and subatomic levels. We cannot 'see' subatomic particles, nucleons or quarks, or even electrons, and we do not need to 'see' them in order to understand their nature.

7. Dec 12, 2009

### Rishav1

so, ultimately, we dont know whether absolute vaccum exists or not?

8. Dec 14, 2009

### pallidin

IMHO, an absolute vacuum cannot exist because of the constant, virtual particle sea that james was talking about.

9. Dec 15, 2009

### rcgldr

Regarding absolute vacuum, what about the void that the universe is expanding into?

10. Dec 15, 2009

### pallidin

Yeah, that starts to blow the mind.
My assumption, without any knowledge, is that the void also consists of virtual particles.

11. Dec 15, 2009

### Wallace

The Universe, as far as we know, is not expanding into a void. Rather than taking this thread off topic though, if you'd like more details there are plenty of threads on this in the cosmology forum that discuss this. Or you could ask a new question there.

12. Dec 15, 2009

### gmax137

You have to tell us what you mean by "absolute vacuum."

13. Dec 15, 2009

### Char. Limit

As far as I can tell, what he means is absolute nothingness. As in, a total and complete emptiness.

I'm also inclined to agree with James, that there is always "something" there. In addition, the wavefunction for any electron orbital never quite terminates (don't ask me to quote SchrÃ¶dinger, I don't know the equation, I just know that the wavefunction is infinite), so there will always be some possibility of there being an electron or something there.

However, I'm not an actual physicist. I'm a "Wikipedia Physicist".

14. Dec 16, 2009

### Neo_Anderson

"Absolute vacuum" is that region of space that's devoid of observable matter and radiations. That means it's a region that doesn't have photons or any baryonic matter. For this reason, an absolute vacuum can exist where there are virtual photons, as virtual photons can't be detected in the first place.
What makes the absolute vacuum impossible? Dark matter/dark energy.

15. Dec 17, 2009

### Rishav1

by absolute vacuum, i mean sumwhere where nothing at all exists....... no atoms..... no subatomic particles...... no nothing........

16. Dec 17, 2009

### Rishav1

if you say about the virtual particles....... then, what about the space between those particles?

17. Dec 21, 2009

### bjornmose

that "sumwhere" would not allow a absolute vacuum (what ever it was) to exist.

On the other hand you can put plenty of nothing that interacts with nothing anywhere as long as it neither takes time or space.
The other way around, it is the existence of something that generates space and time.
Space and time have no meaning if there is nothing that experiences the time elapsing or traveling from A to B.

18. Dec 21, 2009

### Staff: Mentor

Being another wikipedia physicist I can be wrong, but seems to me that while we can't detect virtual photons, we can detect effect of their presence (see Casimir effect). If we can see effect of their presence, that means they do exist.

19. Dec 21, 2009

### HallsofIvy

It's virtual particles all the way down!

20. Dec 21, 2009

### Gfellow

Absolutely. Do not be intimidated by individuals who are by and large very well informed, but in this case have no more data or knowledge about absolute vacuums than you. At best their answers - like mine - are shots in the dark.

It's chicken and egg. Virtual particles form in the proximity to an absolute vacuum. That infers the existence - no matter how temporary - of an absolute vacuum.

21. Dec 21, 2009

### HammerBoy

The word "Absolute" leads to nothing but a "No" to your question.

Even the tiny space between atoms/particles would be filled with radiation, for example, no matter how weak they are. Perhaps this is easier to imagine.

22. Dec 21, 2009

### DaveC426913

Even the vacuum has energy. It's called vacuum energy.

It was set to a non-zero value very shortly after the Big Bang.

23. Dec 21, 2009

### Gfellow

Speculation. Rational speculation, but still speculation.
An absolute vacuum might exist - not as a space with nothing in it, but a volume with no space in it. Keep in mind the mysterious 'dark matter' that no scientist has seriously come to grips with, at least at the time of this missive...

24. Dec 21, 2009

### DaveC426913

So, your argument is: "absolute vacuum might exist because there are things about the universe we haven't solved yet?"

While technically valid, it's a meaningless answer.

I think the original question carries with it the implicit condition "in the universe as we currently understand it".

Last edited: Dec 21, 2009
25. Dec 21, 2009

### pgardn

I would say we cannot say anything about it until the universe expands into it.
From my personal perspective of science and modeling, you cannot model this therefore it really does not exist to us until our universe expands. We can call it a void or whatever but that is giving it a quality. I dont see how we can say anything about "it". I even think it is possible to say the universe creates the idea of space as it expands.

I personally have no problem with saying there is nothing beyond our universe. Just like it seems obvious to me time does not exist without events. I would like a comment to help me in my view(s) if you see an obvious flaw. This is coming from a person who was not trained as a physics guy.