Jump Occlusion

[Murdoc]

Maybe because of the gravitic plating or something, but not because of the ship's mass. You can only consider the center of mass for gravitational equations when none of that mass extends past you. Mass extending past you actually exerts an influence away from the center of mass, lessening the gravitational field at that point. If you are in the center of the starship then the gravitational forces from all the bits of the ship cancel each other out, so the example 100,000 ton mass would have to have a diameter of less than 10 meters to ever exert enough gravity to precipitate out a ship (using my house rule).

I know. That was my turn for a little humor. ""

Feel free to use it. Heck, I may even decide to make it part of my campaign. However, as was pointed out the actual relative speeds are unlikely to be that different and the ships have an entire week in j-space to alter their vectors (according to the book as written). With a week's worth of acceleration even a 1G ship could overcome a vector differential of nearly 6000 km/s. If you were to jump clear to the other side of the Milky Way galaxy, which would pretty much maximize the relative velocity differences short of jumping into a system near the core as it whips around a supermassive black hole, the velocity different would only be about 500 km/s, less than 1/10th of what a 1G ship could overcome.

First of all, nope, you can't: p372 Movement Vector Can Be Changed only works with "non-gravitic" drives, and in T5 M-drive is indeed a gravitic drive (p363). So unless your scout is packing booster rockets, that's not an option.

Second, I don't know if you're accounting for the relative motion of the source world and destination world. Doing a little cocktail napkin math, I estimate that a scout leaving an earth-sized orbit 3 world for another earth-sized orbit 3 world could experience up to a 40% increase in relative speed that would have to be accounted for. That is perhaps enough to handwave away under the calculations a astrogator makes, but it could add to other things, like travelling from a larger planet to a smaller planet.

Last, I did a little looking up on relative motion of stars. Turns out they can be significant. Barnard's Star has a radial velocity of 111 kps, and a traverse velocity of 90 kps, giving a true motion of 140 kps. Now if you have a scout travelling at say, 160 kps at the 100 diameter point, that's a more significant fraction. The nearby star with the largest true velocity (relative to the Sun) is Wolf 424 (at 4 parsecs away) which moves at 555 kps, so it can vary by quite a bit.

 

[esampson]

Just because this is moving so strongly into the area of what it is that the astrogator does and away from occlusion I've busted out my response to another thread.

(kind of the opposite of a thread hijacking, I guess)