If empty space is not really empty, what does the space between an atomic nucleus and its electrons consist of? [duplicate]

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• What is in the space between a nucleus of an atom and its electrons? 2 answers
• Does vacuum (empty space) exist? [closed] 6 answers

I'm currently reading Brian Greene's The Elegant Universe and have also picked up his other book - The Fabric of the Cosmos. In The elegant universe Brian makes up an interesting point that empty space is not really empty. This is according to string theory. Now I may be completely wrong, but lets consider the assumption that empty space is not really empty.

Now there are several analogies to explain the composition of an atom. One favorite analogy says that the atomic nucleus can be considered to be the size of a football placed in the center of a football field, with the electrons moving just outside this field. That's a lot of space! Assuming that empty space is not really empty, what does this atomic space consist of?

Answer 1

It is not empty in the sense that you still have quantum fields present. You also have quantum fluctuations happening all the time, and other quantum phenomena.

Quote from wikipedia: "According to modern understanding, even if all matter could be removed from a volume, it would still not be "empty" due to vacuum fluctuations, dark energy, transiting gamma- and cosmic rays, neutrinos, along with other phenomena in quantum physics. In modern particle physics, the vacuum state is considered as the ground state of matter."

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