Cosmology

As mentioned above, the universe is the experiment of last resort for particle physicists who can no longer command the political will to build larger particle accelerators (the last U.S. project was mothballed when projections ran to $20 billion). Cosmology is a rapidly evolving field, and astrophysicists are constantly fielding instruments that improve the breadth and detail of our observations of the universe.

From this, it would seem that any inferences for particle theory might be subject to frequent revision. In fact, the history of dark matter exhibits just this kind of instability. Every year, there seem to be new and progressively more contradictory constraints on its properties.

Therefore, the list below can only be considered a sketch of this complex and rapidly developing field. It consists of those results crude enough to have survived the observational revolutions of the last 25 years. The epithet (crude) should be taken as a characterization of my currency in this area: much more sensitive measurements are being obtained by improved satellite- and ground-based observatories. I am not an expert in these areas.