If modified gravity is right and verified, it would be the biggest break through in physics since special and general relativity, and would eliminate the need for dark matter, the majority explaination for the same phenomena.
Milgrom is the most famous proponent of modified gravity theory, but he isn't the only one. Moffat is another of the leading modified gravity theorists and his latest paper takes on the Pioneer 10/11 anomaly. I'm not convinced that it is the right solution, but it does have charts showing some decent fits to the data, and he was written a number of other papers which are more convincing. Most notably, he has done better with galactic clusters than Milgrom, at that cost of a more complex theory. You can read the latest paper here.
Hat Tip to Pit of Babel.
Background posts from this blog can be found here, and here, and here.