In this case, the distance is about 17 light years. Really rough numbers, it's about 17 years from the point of view of the ship traveling at .9999c, and about 1200 years from the point of view of someone on Earth. Now a second ship traveling at .5c, it's 34 years from their point of view, but...
In general I'm assuming the same path, or at least close enough that it probably doesn't make a significant difference when traveling at those speeds. I guess the thing that still confuses me is how all of the works out from the point of view of an observer on Earth. My understanding, which...
I've run into a scenario in a sci-fi rpg that I'm running and I haven't been able to come up with a satisfactory answer on my own. Assuming a ship traveling at .9999c, would it be possible for another ship traveling from the same origin to the same destination, but launched later, to arrive...