{ "export": { "source": "https://urth.darkrealm.vip/thread/urth/4169", "note": "Exported from an unofficial mirror of a public mailing list. Copyright in each message remains with the person who wrote it. Email addresses are obscured as `user at host`, the form the original archive published. This file was rebuilt from parsed fields rather than retained headers, so it is faithful in content but not byte-exact.", "addresses": "obscured as 'user at host'" }, "archive": "urth", "thread": { "id": 4169, "subject": "chems on Urth and a FTL Whorl", "messages": 7, "voices": 3, "first": "2003-08-16T17:50:29+00:00", "last": "2003-08-19T07:54:27+00:00" }, "messages": [ { "message_id": "", "from": { "name": "James Wynn", "address": "crushtv at hotpop.com" }, "date": "2003-08-16T17:50:29+00:00", "subject": "Re: (urth) chems on Urth and a FTL Whorl", "in_reply_to": null, "reply_link": null, "blocks": [ { "kind": "text", "depth": 0, "text": "Ash said:\nChems wouldn't be found on Urth at all if they were invented on board the\nShip. Reference Sidero's claims concerning this. Jonas was an exception, and\nhe clearly came from the Ship rather than Urth.\n\nCrush responds:\nAre you saying that the lack of chems in tBotNS is an argument that they all\nfrom \"the Ship\"? But Marble originated on Urth -- in tBotLS she says she saw\nthe original Short Sun. And Kypis seems to recall them on Urth.\n\n\nDon said:\nI'm not qualified to debate this but I think the general consensus is\nthat the Whorl was a sub light speed ship. But I personally think it\nsomehow attained light speed or greater at some point.\n\nCrush responds:\nI think the argument is that a generational ship is unnecessary for a FTL\nship. If it can travel at the SoL, then any trip would be instantaneous for\nthe passengers.\n\n-- Crush" } ] }, { "message_id": "", "from": { "name": "matthew.malthouse", "address": "matthew.malthouse at guardian.co.uk" }, "date": "2003-08-18T09:10:51+00:00", "subject": "Re: (urth) chems on Urth and a FTL Whorl", "in_reply_to": "", "reply_link": "subject", "blocks": [ { "kind": "quote", "depth": 1, "text": "On 16/08/2003 18:50:29 \"James Wynn\" wrote:\nCrush responds:\nI think the argument is that a generational ship is unnecessary for a FTL\nship. If it can travel at the SoL, then any trip would be instantaneous \nfor\nthe passengers." }, { "kind": "text", "depth": 0, "text": "Nit-pick. Any part of the voyage at the speed of light would be \ninstantaneous for the passengers.\n\nAny requirement for acceleration to or deceleration from that speed would \noccasion subjective duration for those aboard. Viz the light-huggers of \nAlastair Reynolds trilogy.\n\nMore \"speed of light\" isn't sufficient. A 30 light year journey would \nstill take minimum 30 years in the external time frame. Practically \nspeaking to make interstellar travel no more an obstacle to empire than \nsay sailing across the Atlantic would require superluminal travel and I'm \nnot sure we even have a theory to suggest what subjective duration would \nbe for those concerned.\n\n\nMatthew" } ] }, { "message_id": "", "from": { "name": "Michael Buice", "address": "mabuice at uchicago.edu" }, "date": "2003-08-18T15:44:38+00:00", "subject": "Re: (urth) chems on Urth and a FTL Whorl", "in_reply_to": "", "reply_link": "subject", "blocks": [ { "kind": "quote", "depth": 1, "text": "On Monday, August 18, 2003, at 04:10 AM, \nmatthew.malthouse at guardian.co.uk wrote:\nAny requirement for acceleration to or deceleration from that speed \nwould\noccasion subjective duration for those aboard. Viz the light-huggers \nof\nAlastair Reynolds trilogy." }, { "kind": "text", "depth": 0, "text": "Strictly speaking there are only technological barriers preventing the \nsubjective duration from being as small as desired. Practically \nspeaking, however, I can only offer a \"yup, what he said.\" \nAcceleration would be the difficult engineering feat." }, { "kind": "quote", "depth": 1, "text": "More \"speed of light\" isn't sufficient. A 30 light year journey would\nstill take minimum 30 years in the external time frame. Practically\nspeaking to make interstellar travel no more an obstacle to empire than\nsay sailing across the Atlantic would require superluminal travel and \nI'm\nnot sure we even have a theory to suggest what subjective duration \nwould\nbe for those concerned." }, { "kind": "text", "depth": 0, "text": "We do, however, have a theory that says superluminal travel completely \nwrecks causality. To my knowledge, no satisfactory solution outside \npolysyllabic vociferation or invoking General Relativity in weird and \nclever ways is known.\n\nMichael" } ] }, { "message_id": "", "from": { "name": "James Wynn", "address": "crushtv at hotpop.com" }, "date": "2003-08-18T18:05:02+00:00", "subject": "Re: (urth) chems on Urth and a FTL Whorl", "in_reply_to": "", "reply_link": "subject", "blocks": [ { "kind": "text", "depth": 0, "text": "Matthew Malthouse wrote:\nAny requirement for acceleration to or deceleration from that speed would\noccasion subjective duration for those aboard. Viz the light-huggers of\nAlastair Reynolds trilogy.\n\nThen Michael Buice wrote:\nStrictly speaking there are only technological barriers preventing the\nsubjective duration from being as small as desired. Practically\nspeaking, however, I can only offer a \"yup, what he said.\"\nAcceleration would be the difficult engineering feat.\n\nCrush seeks clarification:\nOkay. Are ya'll saying that a generational ship *would* be required for FTL\ntravel?\n\nEither way, the One Ship theory would not be bolstered since it would\nrequire endless more groundless hypothesizing to imagine why the Cargo\nshould be transported generationally on Tzadkiel or why it would take\nhundreds of years for them to arrive. Or how the ship got so out of control\nthat orbited the Green/Blue system for 30 years without unloading the Cargo\nand why it hung around the system for another 30 years after unloading.\n\nBut... it would not prevent a my posit that the Whorl *could* be the\nprimitive, infantile Tzadkiel. OTH that sort of theory is helped mostly by\nlimited information, because of the inclination to recycle and re-rig the\ndata available.\n\n-- Crush" } ] }, { "message_id": "", "from": { "name": "Michael Buice", "address": "mabuice at uchicago.edu" }, "date": "2003-08-18T18:59:14+00:00", "subject": "Re: (urth) chems on Urth and a FTL Whorl", "in_reply_to": "", "reply_link": "subject", "blocks": [ { "kind": "quote", "depth": 1, "text": "On Monday, August 18, 2003, at 01:05 PM, James Wynn wrote:\nCrush seeks clarification:\nOkay. Are ya'll saying that a generational ship *would* be required \nfor FTL\ntravel?" }, { "kind": "text", "depth": 0, "text": "Completely orthogonal question. I'm saying that with sufficient \ntechnology to deliver large amounts of power, the generational starship \nis no longer a realistic story. Although it will seem as if 30 years \nhave passed to any proverbial \"Typhon\" back on Urth, the ship can \ntravel such that the entire trip takes as few as a couple of seconds to \nthe passengers, acceleration and all. This is essentially a \ncombination of time dilation and Lorentz contraction (and needs a \ngeodesically complete space-time, but nevermind that). Realistically, \none would imagine some compromise wherein the generational starship \nmakes more sense and is essentially a big rock traveling at constant \nvelocity through space, not fast enough that the passengers won't still \nexperience a great deal of time (as the, I believe, 500 years or so \nsuggested in Long Sun).\n\nFor clarity, all of this is subluminal. Superluminal travel, as I said \nbefore, completely wrecks causality and should be left to fuzzy logic \nand \"heavenly\" Ships. Put it another way, Tzadkiel (or whoever \ndesigned the Ship) would have to know more physics than I do (says the \nphysics grad student).\n\nMichael" } ] }, { "message_id": "", "from": { "name": "matthew.malthouse", "address": "matthew.malthouse at guardian.co.uk" }, "date": "2003-08-19T07:03:40+00:00", "subject": "Re: (urth) chems on Urth and a FTL Whorl", "in_reply_to": "", "reply_link": "subject", "blocks": [ { "kind": "quote", "depth": 1, "text": "On 18/08/2003 16:44:38 Michael Buice wrote:\nOn Monday, August 18, 2003, at 04:10 AM,\nmatthew.malthouse at guardian.co.uk wrote:" }, { "kind": "quote", "depth": 2, "text": "Any requirement for acceleration to or deceleration from that speed\nwould\noccasion subjective duration for those aboard. Viz the light-huggers\nof\nAlastair Reynolds trilogy." }, { "kind": "quote", "depth": 1, "text": "Strictly speaking there are only technological barriers preventing the\nsubjective duration from being as small as desired. Practically\nspeaking, however, I can only offer a \"yup, what he said.\"\nAcceleration would be the difficult engineering feat." }, { "kind": "quote", "depth": 2, "text": "More \"speed of light\" isn't sufficient. A 30 light year journey would\nstill take minimum 30 years in the external time frame. Practically\nspeaking to make interstellar travel no more an obstacle to empire than\nsay sailing across the Atlantic would require superluminal travel and\nI'm\nnot sure we even have a theory to suggest what subjective duration\nwould\nbe for those concerned." }, { "kind": "quote", "depth": 1, "text": "We do, however, have a theory that says superluminal travel completely\nwrecks causality. To my knowledge, no satisfactory solution outside\npolysyllabic vociferation or invoking General Relativity in weird and\nclever ways is known." }, { "kind": "text", "depth": 0, "text": "*Waves Magic Wand*\n\nFather Inire's mirrors side-step all these issues.\n\nMatthew" } ] }, { "message_id": "", "from": { "name": "matthew.malthouse", "address": "matthew.malthouse at guardian.co.uk" }, "date": "2003-08-19T07:54:27+00:00", "subject": "Re: (urth) chems on Urth and a FTL Whorl", "in_reply_to": "", "reply_link": "subject", "blocks": [ { "kind": "quote", "depth": 1, "text": "Okay. Are ya'll saying that a generational ship *would* be required for \nFTL\ntravel?" }, { "kind": "text", "depth": 0, "text": "No. But there would likely be a minimum duration involved.\n\nTo make things simple assume a Newtonian universe and that the ship \naccelerates at 1 g - ie in your cigar-with-fins space ship the nose goes \nforward and the decks are perpendicular to the axis of the ship \nexperiencing a comfortable 1 \"gravity\"\n\nIf a \"starship\" accelerates at a rate of 1 G , its speed is increasing by \n10 m/sec each second. If we divide the speed of light, 300,000,000 m/sec, \nby 10 m/sec^2, we find that the time to reach the speed of light is 347 \ndays.\n\nSo to get to our closest neighbour, Proxima Centauri which is 1541 light \ndays away you have\n\n 347 days accelerating\n 1194 days cruising at the speed of light\n 347 days decelerating.\n\nthat's 1880 days or five years and two months. In the external time \nframe\n\nNow the universe isn't Newtonian but I don't have the maths to work out \nthe relativistic effects. However simplest case, at the speed of light \nthere is no duration so (crudely ignore the acceleration phases) the \ntravelers don't experience those 1194 days cruising so internally on the \nspace ship it's something approaching 690 days. [and I have also \nentirely ignored the fact that at tSoL mass is infinite and would require \ninfinite energy to accelerate to it]\n\nCertainly a generation ship is not required, just something large enough \nthat the passengers don't go mad. \n\nWith such a means of transport the establishment of colonies would be \neminently practical. But I seriously doubt that an effective empire could \nbe maintained once those colonies were productive. If it takes more than \n10 years to send an envoy to the closest star and back political control \nwill fail.\n\nSidebar: thinking about this it occurs to me that Severian experiences \ndecks with useful gravity _parallel_ to the axis of movement of The Ship \nTzadkiel but I can't recall any indication of noticing the Ship's forward \nmotion/acceleration. If that is below the threshold of perceptibility \nthen it's low and attaining the speed of light would be inordinantly long \n- unsurprising for a light-sailing vessel. Yet although aboard some time \n- long enough to re-write his manuscript - it doesn't seem to me that it \nwas a remarkably extended voyage so I'd have to conclude the Tzadkiel does \nnot rely on attaining the speed of light in order to either travel in time \nor make the crossing between Briah and Yesod. Therefore there must be a \nmechanism that is both esoteric and hidden from him (and us). I don't \nthink there is any adequate explanation of Tzadkiel to be had, a wand has \nbeen waved. That being the case I suspect that it is entirely reasonable \nto assume supra-luminal space-flight for the Empire of Man as an \ninexplicable given - perhaps the backswing of the same wand. \n\nMatthew" } ] } ] }