So I was responding to someone's post about the nature of how the island is constantly moving, as mentioned by Ms. Hawking in 316. She said there are electromagnetic pockets all over the world and I think what she meant was that the island is constantly moving from one electromagnetic pocket to another. I also said it is possible that the Black Rock was sailing in one of those pockets when the island popped up in it and that is why it is located in the middle of the island.
This got me thinking. What if the Black Rock was full of people trying to find the island the same way as Ajira flight 316? My theory is that when we discover the back story of Richard it will be revealed that his story is similar to that of John Locke. The people on the Black Rock calculated where the island will be, just like Ms. Hawking did for 316, and sailed to that point in hopes of returning to the island. On board was the dead body of Richard Alpert and he was resurrected upon returning to the island. Since the Black Rock crashed sometime in the 1800's this would explain how Richard has been on the island "forever" like Juliet said. It would also provide an explanation as to why he never ages because he is a resurrected body. I suspect that Locke will now never age from this point and take on a role similar to Richard.