  We argue that a recent discussion of Jetzer and Straumann [Phys. Lett. B 606,
77 (2005)] relating the measured noise spectrum in Josephson junctions to van
der Waals forces is incorrect. The measured noise spectrum in Josephson
junctions is a consequence of the fluctuation dissipation theorem and the
Josephson effect and has nothing to do with van der Waals forces. Consequently,
the argument of Jetzer and Straumann does not shed any light on whether dark
energy can or cannot be measured using superconducting Josephson devices. We
also point out that a more recent paper of Jetzer and Straumann [Phys. Lett. B
639, 57 (2006)] claiming that `zeropoint energies do not show up in any
application of the fluctuation dissipation theorem' violates the standard view
on the subject.
