What's a vacuum?

Question

I know a real vacuum can't exist (third law of thermodynamics and common sense), but what's the closest we can get?

And why the hell can't I wrap my head around something as simple as nothing? It just seems absurd to me, as to the vacuum scientists of old.

A real vacuum would have no energy in addition to having no mass. The third law of thermodynamics implies that absolute zero can never be reached. Deep space is not at all a vacuum, there are photons streaming through all the time in enormous quantities, not to mention all the other crap.

Answer 1

I believe scientists can replicate a virtual vacuum in the lab down to a few atoms per cubic centimeter.

But even if you achieved a 100% vacuum and removed all matter from a volume, there would still exist what makes up that volume.

Answer 2

You are over-thinking the problem and thereby leave the realms of physics and science. Science deals with things that exist. It cares nothing about things that do not exist. A real vacuum by your definition is not a vacuum at all. It would be "nothingness" and that is a term not even philosophy has managed to get a grip on. And philosophy has managed to get a grip on a lot of nonsense.

So the simple answer to your problem is that

"If it ain't exist, it's not good enough for science.".

This is pretty trivial because nature knows herself anyway and practice shows that there are plenty of people who know nature. But... you might not be one of them.

Therefor the more complicated answer is

"If YOU can't tell whether something exists, YOU are not good enough for science."

This is more complicated because it forces you to either get a grip on reality by learning what is and is not real or abandoning all hope that your brain will be able to make sense of it.

But this is not a binary decision! I, for instance, can do general relativity and non-relativistic QM quite well. But don't ask me to perform quantum field theoretical calculations. I can't... and probably never will. That's just the limit of both my mathematical gift and my intuition as a physicist.

If you try hard, you can find out where your limits are. I bet with you that the classical vacuum is not it. You can do way better than that.

Good luck!

PS: We can get quite close to the "real thing". We can make temperatures in the nK range and the remaining excited electromagnetic field modes there are probably undetectable. And there won't be any particles moving around, either, because they will all be frozen out on the walls of your vacuum volume. Nature, of course, won't care. There will be plenty of virtual particle fields left. And since the Planck scale is so high and quantum gravity can not be "turned off", there is virtually no difference for the geometrodynamics of space-time at 0K vs. at 1 million K.There is probably no measurable difference to it at a TeV collision of two quarks, which we will be making plenty off at LHC next year. I will leave it to you to calculate the thermodynamic temperature of a TeV collision in the center of mass system.

:-)

Answer 3

Watch your terminology vacuums are real, they do exist, a perfect vacuum does not exist according to the laws of thermodynamics.

Taken simply a vacuum is a area of low pressure where mass has been extracted creating an "empty" space. No vacuum is perfect in fact the vacuum of space while a high quality vacuum is not a perfect vacuum.

Answer 4

A vacuum, as you say, is nothing, but it is not simple. A vacuum is a region of space where there is nothing, not even air or the tiniest atom. A real vacuum may not exist on earth, but common sense says vacuum can exist, it doesn't say it can't. Outer space is all vacuum, even though there is talk of dark matter and dark energy. There is nothing in space, despite a large portion of it being dark matter. The third law of thermodynamics does not say anything about vacuum. It only speaks of entropy or disorder.

:)

Answer 5

It is possible for an area of vacuum to have matter within it, what defines a vacuum is is a total lack of pressure, if there is no Emery or matter within this area it is a void.

Answer 6

vaccum is nothing but empty space where pressure is 0.
it is also unreactive to any element

actually we can create vaccum but the thing is we have keep on giving energy to sustain it .
Its because in vaccum pressure is 0.
but in atmosphere there is some pressure, it immediately compresses the vaccum space because of its pressure.

something close to this can attained by using
some unreactive inert gases like krypton, radon etc.

Answer 7

A electrical broom

Answer 8

it is an empty space

Answer 9

there is no air in it it is empty

Answer 10

an electrical broom. . .I LOVE IT!!!