Cosmology research has advanced tremendously over the past century. We have moved on from debating whether the Galaxy was the entire universe to observing galaxies at redshifts of 10, from debating whether the universe had a beginning to measuring its age to percent precision, from the first particle physics experiments to the realization that studying the early universe may provide the key to the most fundamental physics theory. Amazingly, in spite of this progress the open questions are no less important than they were 100 years ago, and a continuing collaboration between astronomers and physicists is working to tackle them.

What is the dark matter?

What causes dark energy?

What drives inflation?

How can we use baryons to study the distribution of dark matter?

What is the expansion history of the universe?

How do galaxies form and evolve?

When and how was the universe reionized?

What is the relation between nuclear black holes and their surrounding galaxies?

What could be the signatures of quantum gravity in the cosmic background radiation?