  Microlensing events towards the Large Magellanic Cloud entail that a sizable
fraction of dark matter is in the form of MACHOs (Massive Astrophysical Compact
Halo Objects), presumably located in the halo of the Galaxy. Within the present
uncertainties, brown dwarfs are a viable candidate for MACHOs. Various reasons
strongly suggest that a large amount of MACHOs should actually consist of
binary brown dwarfs. Yet, this circumstance looks in flat contradiction with
the fact that MACHOs have been detected as unresolved objects so far. We show
that such an apparent paradox does not exist within a model in which MACHOs are
clumped into dark clusters along with cold molecular clouds, since dynamical
friction on these clouds makes binary brown dwarfs very close. Moreover, we
argue that future microlensing experiments with a more accurate photometric
observation can resolve binary brown dwarfs.
