Reenvisioning the Invisible: A New Perspective on the Dark-Matter Puzzle

Dr. Brooks Thomas (Hosted by Dev), Lafayette College

Overwhelming evidence now suggests that the majority of the matter in our universe consists of some exotic "dark matter" that neither emits nor absorbs light, yet makes its presence felt via its gravitational pull on normal matter.  Over the years, a number of simple and elegant ideas have been advanced to explain the nature and origin of this dark matter.  However, a variety of puzzling experimental results and tantalizing potential signals have recently emerged which are difficult for these simple proposals to explain.  These results have motivated more complicated proposals for what the dark matter might be, and have even given birth to the idea that our universe might contain a whole "dark sector" comprising a variety of different particles with different properties, all hiding in plain sight.  In this talk, I'll review what we do know about dark matter, explain why traditional ideas about dark matter are being called into question, and describe an alternative perspective on the dark-matter puzzle -- one which in some sense represents the most general approach to that puzzle which can possibly be imagined.  This new perspective brings to light a variety of new possibilities for dark matter whose unusual and distinctive experimental consequences are only beginning to be explored.