Hyperspace is, so I believe, just a fancy name for wormholes. It even looks like a freakin' tunnel. Not that a wormhole would look like that, its just that we imagine them like tunnels. And it fits the bill. You travel irrespective of normal space-time laws as you are essentially travelling through a fifth dimension. But at the same time, space-time does affect you still in such ways as distance and gravity because a fifth dimension is still not an alternate universe.
Also, gravity does not affect hyperspace travel as such, it affects hyperdrives, as is referenced by the technology of hyperspace bubbles, used to "coast" through interdiction fields (basically artificial gravity wells) by inertia alone. This means that hyperdrives probably would use gravity to generate the hyperspace effect which also fits the wormhole theory.
And the big guns on the ships are called turbolasers, not turboblasters. Though, I don't know if this was mentioned, they *are* still blasters, they use Tibanna gas to generate plasma bolts, not laser beams.
One other possible explanation of hyperspace would be that a hyperdrive manipulates the mass signature of a ship to completely elliminate its mass and thus avoid hitting obstacles set by Einstein which stipulated that any object approaching the speed of light would have its mass increase exponentially into infinity, thus making it impossible to generate a thrust powerful enough to propel the ship over the light barrier. With no mass this would not be a problem, you could theoretically reach infinite speeds. Since Star Wars technology knows about gravity manipulation and inertia stabilization, this sort of thing might be possible. It would even explain the rapid acceleration and "drop-out" effects seen by Star Wars ships entering and exiting hyperspace. With no mass you can reach maximum speed (and reverse) in an instant.
