Hear me out people. I know there is a lot of you out there who have strong feelings about if Halo: Reach is a prequel (which I know it was confirmed) or some sort of warped timed event, or just a sequel to Halo 3 or any of the the other theories out there. I believe, it is for sure a prequel (because they already confirmed this). But, for the legendary ending halo 3 cinematic, they have a planet that has the same lines and looks almost identical. You cannot argue that the planet does not look "similar" to Reach. Then again, there are several possibilities here. One, planets just use the same ring shaped structures, it could just be some other human colony. Or, they are BOTH Reach. How could they both be Reach? Reach was attacked by the covenant, but John didnt stay until the end of the battle. They got into slipspace and found the first Halo. This is Halo: Combat Evolved, which takes place just after slipspace travel. Now, if the covenant indeed won Reach, (which by all accounts so far, they pretty much destroyed the place), we have a serious problem. You cant make a game, and then have all the characters die, with all your work as a character ending with you loosing. it just wont work. Therefore, there is a whole lot more to this battle then we ever thought. Unless your playing as Chief. Now if you do, wouldn't it be fitting for the Halo trilogy to end where it started? Because the covenant attacked Reach, Chief went into slipspace and found the first Halo. This makes me think, that Chief and Cortana indeed drifted off to Reach, where Halo started. But what is Chief going to find on Reach? It was destroyed? Whatever is left on Reach, whether it be Spartans or some other race, we will find out at the end of Halo:Reach.
This makes Halo:Reach a prequel to both the Halo series AND the games that will happen after the events of Halo 3. This makes Reach way bigger then we ever could have imagined.