How to See Dark Matter

Sean Carroll at Cosmic Variance has a very nice explanation of a new result that shows that dark matter must exist and that all of the evidence for dark matter cannot be explained away by modifying Einstein’s general relativity. This shows one of the things I really like about blogs. I am in a related field, but I have very little expertise at astronomy. This explanation goes well beyond what I could get in the popular press without being a report for experts only.