  The Gaia space astrometry mission is measuring accurate distances and space
motions of more than two billion stars throughout our Galaxy and beyond. This
is a first look at how Gaia is contributing to fundamental physics, and in
particular to our understanding of dark matter, for which a few examples are
given from the current literature.
  One of our goals is to illustrate how deep, and often surprising, insight
into very diverse areas of fundamental physics can be extracted from this new
and enormous high-accuracy stellar data set. In this spirit, we finish by
suggesting a search for a connection between stellar activity, dark matter
streams, and planetary configuration in nearby exoplanetary systems, as has
been tentatively proposed in the case of the solar system.
