This has been known for a week, you're a little late. It's about time, and I can only guess this is happening now because Chris Cornell's solo career is going downhill fast.
Audioslave wasn't having much success, either. Soundgarden was Cornell's only project that was getting better and better from album to album, IMO. Audioslave and his solo albums got worse as they went along. If only Temple of the Dog would reunite, but I know that they won't...