02162020, 07:30 AM  #21  
Join Date: Nov 2004
Location: Niagara, Canada

Re: Any GURPS stats for black holes, pulsars, etc?
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... I think we just discovered how GURPS Lensmans' writers decided how much shielding to put on that speedster. :) Quote:
Which looks like I should multiply the minimum safe distance around magnetars by around a factor of, say, four or five.
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02162020, 07:44 AM  #22  
Join Date: Jun 2005

Re: Any GURPS stats for black holes, pulsars, etc?
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02162020, 07:51 AM  #23  
Join Date: Jun 2005

Re: Any GURPS stats for black holes, pulsars, etc?
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If the particles themselves aren't free, then they can't move aside faster than light. If your frontal surface is at a 45° angle, then it has to shove them sideways one km to move forward one km; so you can't move faster than light either. You need a more acute geometry to get multiples of c. Though I don't think Smith had worked out the details, for all that he talked about spherical and other shapes of interstellar craft.
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Bill Stoddard I don't think we're in Oz any more. 

02162020, 08:36 AM  #24  
Join Date: May 2005
Location: Oz

Re: Any GURPS stats for black holes, pulsars, etc?
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02162020, 11:26 AM  #25  
Join Date: Nov 2004
Location: Niagara, Canada

Re: Any GURPS stats for black holes, pulsars, etc?
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By the by, does anyone have a GURPS formula for dice of damage from a relativistic kineticenergy weapon? That is, accelerating an object to a measurable fraction of the speed of light before it hits the target? (Smith only lightly touches on the topic in Lensman, but it seems feasible to use STL thrusters to accelerate a 3ton impactor up to speed, fire up a Bergenholm generator to place that missile in a 'free' state, and carry it fairly innocuously towards it target before dropping the Bergenholm field and letting those 3 tons regain its previous intrinsic velocity. I'm wondering how fast such an object would have to be to be able to break through the speedster's wallshield.)
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Thank you for your time,  DataPacRat "Then again, maybe I'm wrong." Last edited by DataPacRat; 02162020 at 11:37 AM. 

02162020, 12:28 PM  #26 
Join Date: Oct 2010
Location: Cambridge, UK

Re: Any GURPS stats for black holes, pulsars, etc?
When I saw the thread title, my first thought was "Uncontrollable Appetite".
The simple calculation for a relativistic collision is a Slam, per p. B371. The speed of light is about Move 3.3*10^8, so an impactor does 3,300,000 dice of damage, call it ten million HP, per hit point it has. This probably underestimates the damage.
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The Path of Cunning. Indexes: DFRPG Characters, Advantage of the Week, Disadvantage of the Week, Skill of the Week, Techniques. Last edited by johndallman; 02162020 at 12:33 PM. 
02162020, 12:29 PM  #27 
Join Date: Mar 2016

Re: Any GURPS stats for black holes, pulsars, etc?
Wouldn't that just be conventional collision rules? Speed of light is about Move 327,000,000, so just multiply mass HP by 3,270,000 (or whatever fraction you want to use) and that's how many dice to use.

02162020, 01:17 PM  #28  
Join Date: Nov 2004
Location: Niagara, Canada

Re: Any GURPS stats for black holes, pulsars, etc?
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... Of course, I'm going to be an annoying physics fan and complicate it up a bit, because relativity is fun. I think I'll take a reasonably high, notparticularlyrelativistic speed, like 0.6c, as a baseline for damage (that is, ObjectHP * 196,200,000d), and for higher speeds, use the ratios of the Lorentz factors instead of straight speeds. That is, 0.6c has a Lorentz factor of 1.250; so an object travelling at a speed of Lorentz 2.5 would do double the damage  that's around 0.915c; a Lorentz of 10 (0.995c) eight times; a Lorentz of 100 (0.99995c) eighty times, and so on. (Or, to make it one step simpler, set damage as ObjectHP*LorentzFactor*156,960,000d.) Now, since we're dealing with a Wall Shield of DR 30,000,000 (which I'm assuming can deflect relativisticlevel masses as well as it can gamma rays), and assuming an average damage roll, then a 1hp object (a 1/512 lb or 0.9 gram homogeneous rock) going at Lorentz 0.05 (1/25th 0.6c's baseline L1.25, meaning 0.024c) would do around 27M damage, enough for the shields to sit up and take notice but not quite let damage through. And a 2hp object (a 1/64 lb or 7.1g rock) would only have to be going half that speed, and so on. 2.4%c... isn't really all that much; the speedster itself can accelerate itself up to that intrinsic velocity in only 38 minutes. It looks like the safe zone around a body with ridiculouslyhigh gravity may be more a matter of how fast the local rubble might have been accelerated to, rather than strictly due to the dangers of the body itself. After all, I seem to recall that the fastestspinning known neutron star twirls at 0.24c, so any tiny bits that get flung off for whatever reason (such as a random rock dropping down onto its surface and disturbing its equilibrium) are going to be moving at quite a clip...
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Thank you for your time,  DataPacRat "Then again, maybe I'm wrong." 

02162020, 01:24 PM  #29  
Join Date: Mar 2016

Re: Any GURPS stats for black holes, pulsars, etc?
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02162020, 01:30 PM  #30  
Join Date: Nov 2004
Location: Niagara, Canada

Re: Any GURPS stats for black holes, pulsars, etc?
Quote:
... Of course, I'm going to be an annoying physics fan and complicate it up a bit, because relativity is fun. I think I'll take a reasonably high, notparticularlyrelativistic speed, like 0.6c, as a baseline for damage (that is, ObjectHP * 1,962,000d), and for higher speeds, use the ratios of the Lorentz factors instead of straight speeds. That is, 0.6c has a Lorentz factor of 1.250; so an object travelling at a speed of Lorentz 2.5 would do double the damage  that's around 0.915c; a Lorentz of 10 (0.995c) eight times; a Lorentz of 100 (0.99995c) eighty times, and so on. (Or, to make it one step simpler, set damage as ObjectHP*LorentzFactor*1,569,600d.) Now, since we're dealing with a Wall Shield of DR 30,000,000 (which I'm assuming can deflect relativisticlevel masses as well as it can gamma rays), and assuming an average damage roll, then a 1hp object (a 1/512 lb or 0.9 gram homogeneous rock) going at Lorentz 5 (0.98c) would do around 27M damage, enough for the shields to sit up and take notice but not quite let damage through. And a 2hp object (a 1/64 lb or 7.1g rock) would only have to be going half that Lorentz (L2.5, 0.92c) speed, and so on.
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Tags 
astronomy, gurps 3e, lensman, space 
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