  The failure to find evidence for elementary particles that could serve as the
constituents of dark matter brings to mind suggestions that dark matter might
consist of massive compact objects (MACHOs). In particular, it has recently
been argued that MACHOs with masses > 15 solar masses may have been
prolifically produced at the onset of the big bang. Although a variety of
astrophysical signatures for primordial MACHOs with masses in this range have
been discussed in the literature, we favor a strategy that uses the potential
for gravitational microlensing of stars outside our galaxy to directly detect
the presence of MACHOs in the halo of our galaxy. We point out that the effect
of the motion of the Earth on the shape of the microlensing brightening curves
provides a promising approach to confirming over the course of next several
years that dark matter consists of MACHOs.
