Quantum gravity drive (quagrav drive) Proposal for a GURPS Space STL/FTL drive system (c)1996 by Stephan Aspridis Theory and specs (what the drive does...): ------------------------------------------ The quagrav drive is both a reactionless STL and a FTL drive sys- tem. In STL mode, it operates by projecting a gravity center, called 'virtual gravity point' (for reasons described later) in front of the ship. As the ship moves, the gravity center moves at the same rate, but remains at a fixed distance, causing a con- stant acceleration as the ship falls into the gravity center it is projecting. For FTL mode, the ship must first accelerate to about .99c. At this point, the relativistic mass gain (about a factor of seven) intensifies the virtual gravity point until a 'graviscalar vor- tex' forms, through that the ship falls into hyperspace. Flight distance and speed are determined by the vectoring of the gravi- scalar vortex. During the fall through the vortex and emerging from hyperspace, the ship creates a weak gravitational shock wave that is detectable over short distances. During the skip through hyperspace, a 'quantum energy layer' sur- rounds the ship, assigning an own microcosmos. Premature collapse of the quantum energy layer while still in hyperspace leads to catastrophic results, usually emerging in another universe. Some contemporary physics (...and how): --------------------------------------- Wait a minute, you say, this is silly. What about Newton? And how is the gravity center supposed to experience a relativistic mass gain? Gravitons are massless particles. And what about the debris the gravity center would attract? Gravity works at infinite dis- tances. Who said anything about gravitons and gravity as we know about now? This drive is called 'quantum gravity drive' for a reason: While we still do not have a quantum theory of gravitation, it is possible to predict how it would have to look like, and some physicists have done just that (they will be mentioned in the sources addendum). Among other things, quantum gravity predicts the existence of two new particles transmitting gravity: The gra- viscalar and the graviphoton. The common graviton is a massless particle with a spin of 2. a so-called tensor, while the two new particles predicted by quan- tum gravity are not tensors: The graviscalar is assumed to be a scalar (as the name implies) with a spin of 0, while the gravi- photon is a vector with a spin of 1. Besides the different properties of tensor-, vector- and scalar- fields (vectorfields can also repel - electromagnetism is a vec- torfield, while scalarfields have no 'orientation'), the most in- teresting thing about the predicted new particles is that they are assumed to have a rest mass! This means that a scalar gravity field (transmitted by a graviscalar) has only a limited range (predicted to be a few hundred meters or a few kilometers at best), while a vector gravity field (transmitted by a gravipho- ton) not only has a limited range, but also repels matter (it still attracts antimatter, though - it is predicted that anti- matter would experience an up to 14% higher gravitational attrac- tion than normal matter). Granted, you say. If the quagrav drive uses a scalar gravity field, there would be a relativistic mass gain of the particles as well as no adverse effects related to debris, as even a field of several million G would not affect anything outside a radius of a few hundred meters. But that leads us to the other question: What about Newton? This would violate a whole bunch of Newtonian laws. True, that is exactly what it means. Quantum gravity pre- dicts that some of Newtons laws will be violated. This is assumed to be possible, because graviscalars and graviphotons are predic- ted to couple differently on matter than gravitons. Gravitons couple with equal strength on mass and bonding force (this is why objects with higher mass have a stronger gravity field). Gravi- scalars and graviphotons don't. Graviscalars are assumed to cou- ple differently on mass and bonding force while graviphotons cou- ple on quantum numbers, like the quantity of baryons, for exam- ple. In nature, violations of Newtonian laws are usually not ex- perienced, because the forces transmitted by graviscalars and graviphotons almost even out (an experiment accomplished by the University of Queensland hinted at a small residual force, how- ever). All right, I have explained now how the quagrav drive is supposed to work without adverse effects and violating physical laws - at least in STL mode. Frankly, for FTL mode there are (by defini- tion) no explanations to make without uttering nonsense, as we simply don't have the foggiest idea whether hyperspace exists and if it exists, how to reach it. So all I can give here is a short explanation of how I think FTL mode works anyway: At 99% lightspeed, the relativistic mass gain of the graviscalars that form the virtual gravity center (virtual, because not gravi- ty but a gravisclar field is used) is great enough to intensify the field until it forms a graviscalar vortex, a kind of pseudo- black hole. Unlike normal black holes, this vortex is a passage into hyperspace and has some other physical properties as well (otherwise it would crush the ship into tiny bits upon reaching it). In hyperspace, the ship must be protected by a quantum ener- gy layer (provided by the quantum energy projectors that are part of the drive unit) that assigns an own microcosmos (I got the idea from GURPS Time Travel - the different quantum levels), be- cause the 5D continuum of hyperspace contains not only our, but every other possible universe as well. So if you want to enter hyperspace, you better do so in an own cosmos (micro- or macro- doesn't matter), because otherwise you end up in a random cosmos (depending on the quantum fluctuations during layer collapse - a great plot device to change campaigns for the GM, though). The number of possible universes is assumed to be finite, but ex- ceedingly high and is determined by the quantity of all elemental particles in the universe times their possible arrangements times all possible impulses and energies. This works fine for time tra- vel as well, as time is no factor in these combinations. All pos- sible variations are already included there, so if you want to time travel, just switch to a different quantum reality (parallel universe, for simplicity). Add to that the possibility of univer- ses with a different quantity of particles, and the number beco- mes even higher. Ah well, but normally, quagrav is only supposed to do the task of STL and FTL travel for you - a task it is ideally suited for, as can be seen below: Game stats: ----------- Quagrav Drive ------------- The quagrav drive produces thrust, that works in a manner similar to the thrust produced by warp engines. One 'thrust factor' will propel 1 ton of mass at 1100G. A standard quagrav engine costs $5000, weighs .5 tons and takes up 1 cy for every thrust factor. Each thrust factor requires 1 MW of power. A ship needs at least a thrust factor equal to it's mass (thrust factor 1000 for a ship of 1000 tons). This means that any ship has at least an acceleration rating of 1100G, which is necessary, because even at 1100G (11 km/s^2) it takes 7.5 hours to reach .99c. Drive type: combined reactionless STL and hyperdrive FTL. FTL Speed: acceleration rating/100 = ly/hr STL Speed: minimum of 1100G, maximum is set by engine mass and size. Fuel: cost, consumption etc.: energy requirements depend on the thrust factor of the ship Ease of FTL navigation: Complex 3-D, with a -1 to the Astroga- tion roll for each 500ly traveled and an additional -2 if no information about the region is available. An hour is re- quired for calculating the course, hur- ried skips give a penalty: -2 for 30 mi- nutes, -4 for 10 minutes, -6 for 1 minu- te and -8 for no calculation at all. Engineering skill dificulty: average, as on p. S35 Obstacles to FTL travel: Acceleration required: In order to skip into hyperspace, the ship first must accelerate to .99c. Upon emerging, the same goes for deceleration. While theo- retically possible that a hostile ship emerges from hyperspace at a planet's orbit, it would do so at .99c and first have to decelerate to do any harm (note that atmospheric reentry at this speeds is not a good idea). Time effects of FTL travel: no effect FTL side effects: no effect FTL error effects: depends on amount by which the Astrogation roll was failed (note that the time effects are due to speed and not time dilation. It will be noticed on the ship that the skip for the calculated distance takes longer than ex- pected): 1-2: Off-position (minor). You emerge nearly at the right destination, but 3d AU away from the calculated reentry point. 3-4: Off-time (minor). You are slower than calculated: Skip takes 3d hours longer than expected. 5 : Combination of the minor effects. 6-7: Off-position (major). You blew it. Ship emerges either (GM's choice) at the cal- culated distance, but in a random direc- tion, or at a random distance in the cal- culated direction. 8-9: Off-time (major). You are significantly slower than calculated: Skip takes 3d*10 hours longer than expected. 10+: Combination of the major effects. FTL special notes: once in hyperspace, there is no way (short of disengaging the drive) to find out whether the astrogational calculations were right or not. STL special note: as the ship is in free fall, there are no acce- leration effects. Drive reliability: checkup every year needed. If missed, roll against Engineering after every 10 uses. A failed roll decreases the thrust factors by a percentage equal to the number of points by which the roll was failed. A critical fai- lure results in a catastrophic failure, limi- ted only by the GM's whim. In the second year without checkup, roll every 5 uses, in the third year every 2 uses and in the fourth year everytime the drive is used. For each subse- quent year without checkup, the engineer gets a cumulative penalty of -2 on his skill roll. Maximum range: limited only by available energy and skill of the astrogator. Designer's note: ---------------- The game stats above are intended for a TL of about 10-12. Feel free to make the drive slower (and probably add some dangerous quirks, too) at TL9, or make it more efficient (by enhancing the thrust factor or decreasing the size) at TL13+. Sources: ---------- Theory and specs is influenced by three drives in SF literature that work on similar principles: The metagrav drive (Perry Rhodan series by various authors) The KK drive (Humanx Commonwealth series by Alan Dean Foster) The AVLO drive (Trigon Disunity series by Michael P. Kube-McDo- well) Contemporary physics is based mainly on two articles that both appeared in the volume 'Kosmologie und Teilchenphysik', published by 'Spektrum der Wissenschaft', the German edition of 'Scientific American': 'Schwerkraft und Antimaterie' (gravity and antimatter) by Terry Goldman, Richard J. Hughes and Michael Martin Nieto 'Das Higgs-Boson' (the Higgs-bozon) by Martinus J. G. Veltman