Hello, I had a question about the Cassimir effect. As I understand it the force is created by an Electromagnetic radiation vaccum created in between two closely spaced metal plates and since only non-half integer wavelengths can exist in this spacing, the plates are drawn slightly closer together... Anyhow my question is this: If some planets have iron cores (ie. mercury), would there be a cassimir effect between them even at such vast distances? I'm guessing that the effect would be very neglible since the unallowed wavelengths would be extremely long and therefore low energy.