Speculation on other information has already begun, such as a Fallen-themed Raid, based loosely upon the Raid cut from the House of Wolves DLC pack.
No other information is out just yet, but the press release for Rise of Iron is scheduled for June, and the expansion should hit shelves some time this fall.
So keep your eyes up, Guardians!
This post on Reddit popped up last night, featuring the poster for the new expansion called Rise Of Iron showing Lord Saladin of the Iron Banner holding a big ol’ hammer and surrounded by the cutest puppies wolves.