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

Staff: Mentor

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 Schrödinger, 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

Staff Emeritus
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.