GypsyComet
Emperor Mongoose
Or jump a tug into the Oort and start nudging stuff around. Only one jump drive that way. It's really long-term planning, but if you hate a neighboring planet enough to play Drop the Rock...
Retained inertia & jump
- Thread starter DFW
- Start date
far-trader said:
Correct. I meant the velocity at the halfway point but, got sloppy typing. Somewhere around there is a good limit to place on speed for M-Drives...
far-trader said:
Right. It is no longer the Doomsday weapon.
far-trader said:
Oh, I didn't drop it because of rocks. I just did it because of the Mach's postulated inertial phenomenon & game mechanic simplicity.
Prime_Evil
Emperor Mongoose
In any civilised SF universe, there will also be strong social controls on the indiscriminate use of this tactic. Dropping rocks on a planet at a substantial fraction of c will be regarded as a war crime akin to the use of chemical or biological weapons against civilian populations. Most sane cultures will regard the tactic with horror and indignation - if anybody with a grudge is allowed to do this, things will get ugly very fast. Also keep in mind that if you hit a planet with enough rocks, you will render it uninhabitable for decades due to the effects of a 'meteoric winter'. Remember the righteous anger of the Terrans when the bugs used this tactic against Buenos Aires in Heinlien's Starship Troopers?
In the OTU, I think it is reasonable to regard the indiscriminate use of asteroid bombardment is a violation of the Rules of War akin to the use of other weapons of mass destruction. The Imperium will spare no resources to bring the perpetrators to justice as war criminals because they don't want other groups getting the idea that this is a socially acceptable way to resolve your grievances.
I imagine that most planets that are high-tech and high population will have adequate defenses to defeat this tactic. Even at a substantial fraction of c, they are going to notice an object accelerating towards them out of the Oort cloud long before it gets close enough to be a threat. Remember that it takes light an average of 5.5 hours to travel from the sun to Pluto (the exact time varies due to the dwarf planet's eliptical orbit) - and that's travelling at the speed of light. Even with 10 G of continuous acceleration, it takes roughly 85 hours to accelerate an object to 10% of the speed of light. This will give target planet plenty of time to detect the incoming missile and respond.
Personally, I think that this tactic is only viable against low-tech planets or ploanets with such a low population that they can't maintain automated monitoring systems and orbital defenses against the threat.
In the OTU, I think it is reasonable to regard the indiscriminate use of asteroid bombardment is a violation of the Rules of War akin to the use of other weapons of mass destruction. The Imperium will spare no resources to bring the perpetrators to justice as war criminals because they don't want other groups getting the idea that this is a socially acceptable way to resolve your grievances.
I imagine that most planets that are high-tech and high population will have adequate defenses to defeat this tactic. Even at a substantial fraction of c, they are going to notice an object accelerating towards them out of the Oort cloud long before it gets close enough to be a threat. Remember that it takes light an average of 5.5 hours to travel from the sun to Pluto (the exact time varies due to the dwarf planet's eliptical orbit) - and that's travelling at the speed of light. Even with 10 G of continuous acceleration, it takes roughly 85 hours to accelerate an object to 10% of the speed of light. This will give target planet plenty of time to detect the incoming missile and respond.
Personally, I think that this tactic is only viable against low-tech planets or ploanets with such a low population that they can't maintain automated monitoring systems and orbital defenses against the threat.
Here is a followup question then:
CT assumtions for the travel table are start at zero velocity and end at zero velocity. (LBB 2, pg 4, 2nd para under interplanetary travel.) The table and associated formulas are provided to assist in determining travel times in system and to 100d safe jump.
Is it then safe to assume that a ship must be at zero velocity in order to transit to jump? CT LBB2 doesn't go into detail about jump transition but MGT talks about creating an artificial singularity and and pumping high-energy exotic particles into it. I think that might be difficult to accomplish while traveling at 334,664 m/s (5G for 1.12 million KM - Jewel is Size 7 with a diameter of 11,200 KM * 100d limit = 1,120,000 KM).
The time to reach the 100d limit would vary as well; same scenario takes 157.76 minutes (0 to 0 velocity) or 111.55 minutes (0 to 334,664 m/s).
In MTU, the ship must come to 0 velocity to enter jump. Therefore there is no question of a residual vector on exiting jump.
CT assumtions for the travel table are start at zero velocity and end at zero velocity. (LBB 2, pg 4, 2nd para under interplanetary travel.) The table and associated formulas are provided to assist in determining travel times in system and to 100d safe jump.
Is it then safe to assume that a ship must be at zero velocity in order to transit to jump? CT LBB2 doesn't go into detail about jump transition but MGT talks about creating an artificial singularity and and pumping high-energy exotic particles into it. I think that might be difficult to accomplish while traveling at 334,664 m/s (5G for 1.12 million KM - Jewel is Size 7 with a diameter of 11,200 KM * 100d limit = 1,120,000 KM).
The time to reach the 100d limit would vary as well; same scenario takes 157.76 minutes (0 to 0 velocity) or 111.55 minutes (0 to 334,664 m/s).
In MTU, the ship must come to 0 velocity to enter jump. Therefore there is no question of a residual vector on exiting jump.
far-trader
Mongoose
D-Foxx said:
But zero velocity relative to what frame of reference? That's been the 800 pound gorilla on the bridge for decades. And his buddy has been the huge vector/velocity difference inherent in traveling across light years to another star system.
GypsyComet
Emperor Mongoose
D-Foxx said:
"Zero" velocity is still relative to the inertial frame of reference of the system you start in.
IMTU I don't worry about it particularly. Jump calcs must have a predictable entry point and velocity, but otherwise its all good. A ship required to jink wildly, or that needs to change course at 99 diameters, will need to recalculate for the new velocity and entry point.
far-trader
Mongoose
DFW said:
Two of the best reasons I've seen
Pick your brain time
...would this work as well or better for the departure and destination gravity wells? I've often felt what should be happening is a balancing of the tidal forces in the jump plot. So 100d departure from a size A world is going to put you at 100d from a size 3 world. With your zeroed vector relative to the world...
...of course then what about deep space jumps, and stellar 100d shadows, and... my head hurts
GypsyComet said:
That's how I view it. You are calculating from point A to Point B. Both being definite. That's why you can calculate while travelling to 100D. the astrogator sets the course and gives to the pilot. The pilot knows he needs to be at "Point A" at x time so that the Astrogator's calculations correctly apply.
On entering jump - zero relative to the primary you are departing.
On leaving jump - zero relative to the primary you are arriving at.
It's all part of the astrogation/ploting required, the jump software for executing the jump, and a function of the ""tiny parallel universe" in which the ships travels.
I understand that we play a game that is considered to be "Hard Science Fiction". However we all try to explain or wave away things like jump drives, artificial gravity, inertial compensators, but then get caught up on the fact that everything in the "universe" is moving and and want to know velocity relative to? Zero velocity can't exist? Some times the explanation is ... because the GM says that is how Jump Space works.
rust said:
If we use the formulas from LBB2 in conjunction with the travel time table, which is the same in LBB2 and the MGT CRB, to determine time to move between interplanetary bodies without accounting for their movement, then why worry about the movement of interstellar bodies when performing interstellar travel? Same assumption - depart at zero, arrive at zero.
Because the jumpspace would have to know which of the bodies of theD-Foxx said:
destination system the ship's crew intends to visit, in our system for ex-
ample which of the moons of Jupiter, in order to release the ship with the
right velocity and vector. This is a bit too much for my suspension of dis-
belief.
YTU your system/explanations. MTU my system/explanations. The glory of the game we play is that I doubt any body plays/explains it the same way. I like seeing others' ideas, but I just think some times people go a little too far down the hard science rabbit hole. It is a game...right? :?
GypsyComet
Emperor Mongoose
rust said:
Whenever I make a reference to the Ephemera, I'm talking about the "current" navigational data for the system you are in and the system you are heading for. This is a fairly trivial data set to get updated as you travel around, and is one of the side benefits of having all ports be under one authority (the Imperium, or whoever) in a large area.
If you *want* your Jumpdrive to provide some non-zero velocity relative to the target system, this would be part of the jump calculations (informed BY the ephemera), subject to the usual "jumpspace is weird" errors, and probably not capable of imparting very much velocity regardless. The desired results affect the calculations and thus the twisted physics generatd by the drive. Results a week later are a slight velocity bias in the direction you wanted. You hope.
Alternately, a Jump drive could "borrow" inertial reference from the Jump Horizon it bounces off of during emergence. This means that you either require a mass for emergence (not supported by Canon, but hey, its your game) or that an emergence mass simply makes this operation *easier*.
A collapsing jump field imparts to its contents the inertial frame of reference of the mass that caused the emergence, or whichever local gravitational field is strongest at the point of emergence. This means that NO, you won't be run over by that world you just popped in front of, because you emerge stationary relative to it. You *might* get run over by a moon that is skating the planet's Jump Horizon, however, or a planet that is skating the star's Jump Horizon.
If you emerge in open system space, the primary star's gravity is likely the strongest jump-relative force around, so you will emerge stationary relative to the star. A planet whipping along nearby is going to overpower the star's local pull long before you are too close to dodge, so a mild navigational error could find you emerging in the Inertial grip of the wrong planet, but for ships with even 1g of thrust, this is pretty trivial unless you were working that last few m3 of fuel when you emerged.
This is not about science, Traveller's jump drive is as non-scientific as isD-Foxx said:
possible anyway. It is purely about consistency and plausibility. They are
important for me, especially because the players will hit me over the head
with any obvious bug in my description of the universe. But this is just my
way to see the game, in no way an expectation that others would do it in
a similar way.
Dropping an asteroid on a planet that has modern weapons to destroy said asteriod is pretty stupid idea. The amount of resources required to do so could be spent on a more covert weapons delivery system that would be nuclear, or biological or chemical. Any of these would be far harder to stop than an asteroid.
If you want to take out planetary targets you could simply target them with flying crowbars like the old Project Thor. Except this time you could boost them from a billion km's away, let their engines burn out, and then gravity will do the work for you.
If you want to take out planetary targets you could simply target them with flying crowbars like the old Project Thor. Except this time you could boost them from a billion km's away, let their engines burn out, and then gravity will do the work for you.
GypsyComet
Emperor Mongoose
phavoc said:
An Albedo Blitz, yes. Nasty, and hard to stop once its had a chance to get moving.
rust said:
I understand. Like I said, it's a game and no one will ever play it exactly the same. If it's important to you, and your group pays that much attention to that type of detail, have at it.
When I mention the rabbit hole it is probaly more about what some people choose to nit pick. I've just seen people, not on this board, look at a picture someone submitted and say that the archetecture of a building in the backgound was "unrealistic" while the 600ton frieghter hovering next to it goes unmentioned. :?
