Do atoms exist in a vacuum?
does eletromagnetic radiation exist between atoms and to what extent?
I don't think the question has anything to do with QM: whether a space is a vacuum or not has nothing at all to do with whether there is EM radiation in it.....and there's always EM radiation in it.
That's the assumption that'll get you.
I guess it all depends on how hypothetical the OP wants to get. You can find volumes of a few cc of perfect vacuum in space, but these spaces have EM radiation traveling through them. That's the answer to the OP's questions in reality: You can't, in real life, have a space with no EM radiation traveling through it.
So if the OP wants to assume a space completely insulated from EM radiation, then s/he will have to be specific about which scientific laws should apply to this space and which shouldn't. And the answer depends on the choice of assumptions.
I guess what I'm really trying to get at is, if a vacuum is filled with eletromagnetic radiation, can it be classified as a "perfect vacuum"?
Sorry, for not being clearer... I'm having a discussion with someone else. And, he's insisting that nothing exists between atoms. I beleive that electromagnetic radiation does. But, since as he claims, he's the "expert" on the subject, my arguing with him is pointless.
Yes - by definition.I guess what I'm really trying to get at is, if a vacuum is filled with eletromagnetic radiation, can it be classified as a "perfect vacuum"?
No worries - I have a seventh sense for this sort of thing.jarednjames said:Well, I'm way off then.
Apologies russ, seems like you were on the right track.
1. If arguing is pointless then don't argue.
2. Atoms are made of charged particles (or waves if you prefer). The theoretical limit for the range of the electrostatic force is in the billions of light years so I would say that electrostatic force would exist between 2 atoms in an otherwise completely empty universe unless they are very far apart. If the 2 atoms are moving with respect to each other then electrostatic would also imply electromagnetic.
3. In our universe atoms and EM are not the only candidates for occupying a vacuum. How about neutrinos, dark matter, and dark energy for starters.
Yes - by definition.
At this time, theory only.
Do you have any references to support your answer?
Thanks. I'm not looking to support an argument with theory.
Do you have any references to support your answer?
In everyday usage, vacuum is a volume of space that is essentially empty of matter, such that its gaseous pressure is much less than atmospheric pressure. The word comes from the Latin term for "empty". A perfect vacuum would be one with no particles in it at all, which is impossible to achieve in practice.
A vacuum is defined as being a place where there is an absence of matter not em radiation. Don't confuse the two.
You should learn the difference between arbitrarily defining something for the sake of making arbitrary claims and actually reasoning about the logic of the concept. A vacuum may be generally viewed as referring to an absence of matter but not energy, but the relevant issue is why.
You should learn the difference between arbitrarily defining something for the sake of making arbitrary claims and actually reasoning about the logic of the concept. A vacuum may be generally viewed as referring to an absence of matter but not energy, but the relevant issue is why. To get into that, you need to reflect on what really constitutes "vacuum" and what its purpose as a descriptive term is in the first place.
My impression (though I'd like to know if others see it differently) is that a vacuum refers not only to the absence of matter but also to the potential for matter and/or EM energy to be present. If there was some possibility for a vacuum to exist in which neither matter nor radiation could be present, would space even exist there?
I suppose you could go on to ask the question that if it was possible to have a vacuum devoid of both matter and radiation, would gravitational force still be present? How would it be possible to have a vacuum devoid of all matter, energy, and force? How would that even be measurable/observable at all?
So, given the definition, as meaning, the absence of matter but not necessarily the absence of electromagnetic radiation, can eletromagnetism have any affect on the velocity of light?
The answer to "why" is that this is how people communicate, words are "arbitrary" and mean what we (by consensus) want them to mean.
The word "vacuum" simply mean absence of matter, and the reason for this is that it is how the word has been used for the part 200 years or so. This is a question of etymology; not philosophy. As far as I know there is no word that means "absence of EM radiation", but of course there is nothing that prevents you from making one up.
This is essentially the issue of whether scientific terminology and concepts are (or should be) based on traditional authority or rational authority. If there is no basis except tradition for scientific terms and concepts, why should anyone ever subject them to critical rigor in any form. Shouldn't theories then simply be accepted by definition and contradictions and other problems within them ignored?I gave you the definition from three sources. It does not involve EM radiation.
This isn't a contest of proving one definition is more established than another. It is about dissecting the concept of "vacuum" to understand it better, why or why not radiation and/or force should be considered in terms of vacuum-analysis, and why.Now if you want to give me another source that shows a vacuum is connected to radiation levels I will happily consider your above statement.
How about "we" stick with discussing the topic and avoid making statements that imply collective domination, like "we vs. others." This is an aggressive discussion style.Until then, we'll stick with the agreed upon definition.
Now you're saying that it is irrelevant for someone to ask a scientific question about vacuum-operationalization because of definitional traditions? Why shouldn't Galileo have just submitted to the traditional definition of the heavens as being all massive bodies surrounding the Earth and therefore continued to analyze the heavens as centered around the Earth? His science was to explore reasons that it might make analytical sense to define planetary-motion in another way. Even if he would have been wrong, there was no reason to chastize him for exploring the issue.The "relevant issue" as you put it is not why, that question has never been raised. Besides, a vacuum is simply a way of describing a system where there is no / little matter - it doesn't need to mention radiation because that isn't what is being described.
I'm not claiming to be able to answer this but I want to add something to your question because I think it is interesting. If electromagnetism wouldn't have any effect on the speed of light, how could light slow down in a medium whose volume primarily consists of atomic/molecular electrons?So, given the definition, as meaning, the absence of matter but not necessarily the absence of electromagnetic radiation, can eletromagnetism have any affect on the velocity of light?
I'm not claiming to be able to answer this but I want to add something to your question because I think it is interesting. If electromagnetism wouldn't have any effect on the speed of light, how could light slow down in a medium whose volume primarily consists of atomic/molecular electrons?
Wouldn't insisting on definitions and the reasons for accepting them also belong in the philosophy section then? If someone in the thread brings up the issue of whether a vacuum can or should also be free of radiation and/or force, why shouldn't the scientific issues related to that be discussed? You avert this discussion by making it purely about definitions. This is obstructing scientific discussion, isn't it?Brainstorm, a vacuum is an area devoid of matter. That's it. That's why it's the end of the story.
It's not meant to describe the radiation content. It deals purely with matter.
The scientific label for an area that lacks matter is a vacuum.
If you want to create a word to deal with the lack of radiation then go ahead.
Please take your philosophical questions to the philosophy section. Stick to the scientifically accepted definitions here.