>Casimir effect >using ‘free’ energy borrowed from nothing Vacuum energy pressure, like gravity, will bring the two plates together, but pulling them back apar

>Casimir effect >using ‘free’ energy borrowed from nothing Vacuum energy pressure, like gravity, will bring the two plates together, but pulling them back apart will take energy (again, just like with gravity or even a spring), and so doesn't show much promise as a perpetual motion machine.