On Wed, Dec 20, 2017 at 1:07 AM, Rob O'Connor <xxxxxx@ozemail.com.au> wrote:

Craig Berry wrote (of stutterwarp):
> It conserves linear momentum, and also energy if you make each
> microjump pay the potential-difference cost.

The gravitational potential of the nearest most massive body?
What happens in interstellar space?

The total gravitational potential field. So in relatively flat space, there's no extra cost (or benefit) from each microjump due to potential difference. I don't recall how detailed 2300's rules about this were, but I always pictured it as there being a fixed energy cost for the microjump itself, plus the cost of the potential change. If you're going "downhill" you can actually recover energy and offset some of the fixed cost. Stutterwarp doesn't work in space curved enough where the gain would be greater than the fixed cost.

Is the effective velocity limited to escape velocity e.g. from the surface of our sun moving in our solar system?

I can't see any reason why it would be. Again, I don't remember the rules, but my head-canon is that the cycle time between microjumps is fixed for a given design/tech level, and the maximum length of a microjump gets longer the flatter the gravitational potential field is. So you can go very fast in interstellar space, but start slowing down inside a star system, and hit the limit where stutterwarp doesn't work any more in the inner system or near a planet.

> It's still physically impossible (e.g., it violates conservation of
> angular momentum, allows signals to exceed c, etc.)

FTL information signalling is only problematic if it allows useful causality violations. Misjumps in Traveller are the cosmic censorship hypothesis writ large ;-)

Traveller jumps (or anything else carrying information FTL) can be made to produce causality violations; it's all about picking the right observer reference frame. And I like that formulation for misjumps. God to characters: "Hey, knock that off!" :)

"Eternity is in love with the productions of time." - William Blake