[dedward]

It's important to realize these predictions were not all separate things - where he just said "Oh hey, what about X?"

He developed mathematical models for currently available observations. Those models in turn also suggested other phenomenon that could not be measured at the time. As time went on, some of these have been measured and found to hold true, others observations about the universe have been had that suggest they don't hold true in all cases (eg: "dark" stuff)