Anthony Jackson wrote: > Jon Lang wrote: >> If I have accelerations that let me travel a parsec in a month, then I >> have enough acceleration to go anywhere in the galaxy in 20 years. >> Barring navigational hazards, of course: there may be a practical top >> speed based on the density of the interstellar medium - if you go too >> fast, even that near-vacuum will be too much to handle. > > Why deal with acceleration to start with?
Personal preference, for one thing. Every FTL drive that GURPS deals with dispenses with acceleration; I want to do something different, with an FTL drive that's closer in principle to the grav drives from the old Vehicles Expansions (i.e., a reactionless drive that produces pseudo-velocity and ignores the lightspeed cap). > At a minimum, any such drive > should pay for the potential energy differential between two locations, > and that will just apply a speed limit that depends on the local slope > of space (i.e. is inversely proportional to the local gravitational > field). As I've indicated before: to the extent that gravity interacts with this propulsion system, I want to use the tidal forces as a baseline. Actual gravity produces tidal forces; acceleration-based pseudo-gravity does not. > At 1 kW/kg, which is a reasonable power density, escaping earth > (potential well: 62 MJ/kg) takes 17 hours and your surface velocity is > limited to 100m/s, escaping the sun (potential well: 860 MJ/kg) takes > 240 hours and your velocity at 1 AU is limited to about 160 km/sec, and > reaching a nearby star is actually quite cheap in potential energy > terms but may still have a velocity limit. If I'm understanding your numbers correctly, the speed limit at 100 AU would be 16,000 km/sec, or approximately 6% of lightspeed. At 1000 AU, this would increase to 6 times lightspeed; and at 10,000 AU, you'd be traveling at 600 times lightspeed. IIRC, that gets you into the Oort Cloud. -- Jonathan "Dataweaver" Lang _______________________________________________ GurpsNet-L mailing list <[email protected]> http://mail.sjgames.com/mailman/listinfo/gurpsnet-l
