I was pleased to get a comment from cosmologist Sean Carroll frighteningly soon after starting this thing up. Here’s some questions about cosmology that have been on my mind recently, maybe he or someone else will be able to answer them:
Witten has argued to me that “results about CMB fluctuations which are suggestive of inflation at the GUT scale” provide evidence that “grand unification is on the right track”. What exactly does the CMB data say about inflation? Can one extract the GUT scale from either the current CMB data or any conceivable better future CMB data?
More generally, while I’ve heard a lot about attempts to extract information about Planck-scale physics from CMB data, what about all the scales in between where accelerators stop (hundreds of Gev) and the Planck scale? Can one find out anything about electroweak symmetry breaking? Could this have anything to do with inflation?
There’s another question that often bothers me: “How can you have a field called ‘String Cosmology’ when string theory isn’t really a theory and can’t be used to predict anything?”, but I’ll be good for now and leave that rant for another time.