Is there an absolute minimum quantity of matter per unit of space?

Question

If there is it would mean a total vaccuum is impossible.

Does it really compare to waves Bob W, could you explain?

Ernie F - think of the 'vaccuum' if it was attempted with the famous hemispheres. Not naturally occurring as I imagine you thought I meant. I also said possible rather than observable.

Oh - you were referring to Andrew's comment.

Answer 1

No. If you've ever studied waves (not ocean waves) you know this to be true.

Answer 2

I thought I knew what you were asking by the question, but after reading the comments, I'm not sure.

According to string theory, the fabric of space is itself made of one dimensional vibrating strings of energy (mass-energy) one Plank length (about 10^-33 cm). Thus, space is a something, not a nothing.

Because space is a something, there will always be a quantity of matter (mass-energy) per unit of space. Thus, there will always be a mass-energy per unit of space greater than 0.

What is unclear to me, and others, is what that string-space minimum density might be. When, for example, does the "fabric of space" become so much cheese cloth full of holes? And how would those holes show up in four dimensional (4D) space?

What is further unclear is whether that string-space minimum density is uniform or variable over space-time and whether the unit of space used in string density calculations makes more sense in 4D or 11D space-time.

Answer 3

No. But the question of whether a perfect vacuum would be observable is quite another (and completely abstract) question. Mass (matter) occuppies the amount of space that it warps. The warping of space approaches 0 as the center(s) of mass increase in distance but never quite reaches 0.

Answer 4

I think it depends on establishing for sure if space (distance, volume) is quantised. If space is not quantised then you could have a perfect vaccuum atleast on some size scale.

Answer 5

keep in mind 2 factors. 1 due to quantum mechanics, matter can appear spontaneously, therefore if an area of space is empty (and you are somehow able to observe this) at one moment, it might not be empty at another moment. 2 string theory reminds us there are different dimentions to look at and the size of matter at it's most elementary level is too small for us to be able to detect.

Answer 6

Because of Heisenberg's uncertainty principle, you can never know -precisely- how much matter there is in any given volume. Therefore you can never -observe- a total vacuum.

Answer 7

exactly