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Quote by: Jack  Certain words mean different things in different contexts, and in this case "nothing" is a matter of scale. On the scale of human eyesight, you could indeed have an empty box that contains nothing. On the molecular level that's less likely. If I can see the box is empty that means there are light particles in the box. There's also oxygen and hydrogen, among thousands of other molecules. Drop down to the sub-atomic scale and I doubt you could ever have an empty space anywhere. |
And if you pump it down to total vacuum and absolute zero and then find a way to keep neutrinos out, you still have virtual particles.
Once I saw the designs for a device called a Casimir engine. The idea was to put two metal plates so close together that virtual particles could not appear between them, resulting in a space with negative energy density relative to the rest of the universe. In other words, a box of nothing.
But would it really be empty? Does spacetime itself or the Higgs field count as something? Physicists spend a lot of time arguing about nothing and still do not understand it fully.
If people want to understand this as well as anybody does, which is not that well, watch this series of videos.
YouTube - The Mystery of Empty Space 1