  We discuss some low energy properties of color-flavor locked (CFL)
superconductors. First, we study how an external magnetic field affects their
Goldstone physics in the chiral limit, stressing that there is a long-range
component of the field that penetrates the superconductor. We note that the
most remarkable effect of the applied field is giving a mass to the charged
pions and kaons. By estimating this effect, we see that for values $e B \sim 2
f_\pi \Delta$, where $\Delta$ is the quark gap, and $f_\pi$ the pion decay
constant, the charged Goldstone bosons become so heavy, that they turn out to
be unstable. The symmetry breaking pattern is then changed, agreeing with that
of the magnetic color-flavor locked (MCFL) phase, recently proposed in
hep-ph/0503162. Finally, we discuss the physics of the superfluid phonon of the
CFL phase, compare it with that of the phonon of a Bose-Einstein condensate,
and discuss transport phenomena at low temperature. Astrophysical implications
of all the above low energy properties are also commented.
