Time Travel in a Traveller campaign

[Werner]

Not worth it. That's only true now because we're selling it to them. Just one lifetime ago (80 yrs) it wasn't so. There were whole countries that had no electricity. Heck, there were parts of the USA that only got electricity courtesy of FDR's rural electrification project. There were islands that had never seen a ship or airplane before WW2, started cargo cults, etc. The African interior was equally deprived, technologically.


A planet isolated by trade collapse, with a local collapse of civilization, could easily get them back to using steam and maybe forgetting about high tech entirely. Strand your players there with almost any kind of maintenance problem and there are no resources for them to repair the ship.


Just as bad. Time travel can't happen by accident, like the guy with the chocolate bar and the guy with the peanut butter jar bumping into each other. In a milieu such as the OTU, a one-in-a-billion accident would happen regularly, maybe once a month. The chance of it happening to you is still so small that it becomes an implausible plot.



If time travel could be possible it would take stupendous amounts of energy even by scifi standards of near-limitless power (maybe mc² per second traversed). It would take precise manipulation of space time with exotic matter and super-duper handwavium fields, not something that can just happen. And if it can happen once, it can be duplicated. Only a stupendous energy requirement would prevent it from becoming the Temporal Authority intervention of the week.

I got an idea for a time machine:

Step 1: Create a wormhole. A Jump drive is comparable to a wormhole, so if the Imperium is capable of building a jump drive, wormholes are not out of the question. Assume both end of a wormhole can be created close together, each end of the wormhole can be moved independently of the other, and the distance and time moves at the same rate for both ends of the wormhole as seen through the inside, but as viewed from the outside, you can time dialate one end to a different degree than the other.

Step 2: Accelerate one end (mouth) of the wormhole to near the speed of light, time slows down for that wormhole mouth as seen from the outside as compared to the other wormhole mouth that is left at the point of origin, but seen from the point of origin through the wormhole it is not slowed down at all, in fact the rate of time for universe seen from the high speed wormhole mouth is speed up due to relativity, so that end is moving into the future faster than the other, this shortens the travel time to distant points in space.

Step 3: Move the traveling end of the wormhole towards a cosmic string, a cosmic string is a leftover from the big bang, it is a naturally occurring time machine as old as the observable universe, this could be about one billion light years away, there is evidence for cosmic strings existing due to the way galactic super clusters are distributed in string like formations throughout the Universe. You use the cosmic strings as a time machine to move your traveling end of the wormhole back in time to before you created your wormhole.

Step 4: Move the traveling end of the wormhole back to Earth, you can return to Earth millions of years in the past, you could terraform Venus and Mars and have plenty of time to do it, after you terraform those two planets, you can move plants, animals and people from Earth to Venus and Mars, and you can time dialate the traveled wormhole mouth back into the future to shorten the process of terraforming those planets until you reach the year 1864 then you step through the wormhole and mess with history on Earth just a bit. You can incorporate the wormhole to be a part of your jump drive, you can keep the wormhole open a tiny bit such as the width of an atom, and then you can expand its throat greatly to allow passage of a Starship, and the you contract it again to the width of an atom, this all happens extremely fast so it looks like an ordinary jump drive in operation. This time machine only goes to one time period in a parallel Universe and back because there is only one wormhole, so you can't do all those grandfather paradoxes as the wormhole connects to seperate timelines, one is not directly connected to the other.

 

[Werner]

And if it could be duplicated, it would be. This would lead to the standard time travel problems, like would-be Hitler-assassins running into each other or an impossibly large crowd at The Crucifixion.

One catch is that if there was any action that could make time travel impossible, and a transfinite future in which time travel is possible, with a similarly transfinite number of time-travelers, one of them will eventually do that very thing and block time travel for everyone permanently.

And I still like the central conceit of Niven's "Rotating Cylinders and the Possibility of Global Causality Violation".

Spoiler:

The universe itself hates time machines, and thus a series of increasingly implausible and catastrophic coincidences will ensure that none will be completed.

If time travel is accomplished by means of a wormhole, then each wormhole leads to one parallel timeline in the past, you can kill Hitler in the parallel timeline, but that only affects events in the parallel timeline, not your own. Moving a wormhole end near the speed of light and taking it to a cosmic string for backwards in time travel is kind of a big deal, so you don't do that casually, and it is not a matter of just setting the dials, picking your date and traveling to the past, the time it travels to is already set, you can only move it further into the future in that parallel timeline, and that is kind of a big deal as well. If you mess with history in that parallel timeline it doesn't affect your own. So you basically have one period in a parallel history past you can travel to and come back from, none of this grandfather stuff, no paradoxes because they are seperate but similar universes

 

[BRover]

Fixing a problem in the past means the future you return to is not the same as the future you came from.

As an aside have you looked at any time travel rpgs? Time and Time again is one of my favourites, and EABA has quite a nice time travel game in Timelords.

True--but isn't that part of the reason to go back? To change the future/present?

It depends on how malleable the timeline is. Will small changes tend to damp themselves out over time? Are there specific critical changes that have major effects?

Personally, I suspect that chaos theory (butterfly effect) means that there will be noticeable effects--but in details more often than in grand course of history and culture. Just as in weather effects: small changes in the sixth or seventh decimal change the outcome, so the hurricanes, say, follow different tracks--but there will be a similar set of storms in a given season, because the ocean heat driving the storms is still there.

 

[BRover]

. . .

If time travel could be possible it would take stupendous amounts of energy even by scifi standards of near-limitless power (maybe mc² per second traversed). It would take precise manipulation of space time with exotic matter and super-duper handwavium fields, not something that can just happen. And if it can happen once, it can be duplicated. Only a stupendous energy requirement would prevent it from becoming the Temporal Authority intervention of the week.

Worse: Consider the effect of time travel from the perspective of the points in time when the time machine departs or arrives. When the machine and its contents disappear, there is a huge loss of energy/mass and information; when it appears, there is a gain in both. Which contradicts some very basic laws of physics.

 

[BRover]

And if it could be duplicated, it would be. This would lead to the standard time travel problems, like would-be Hitler-assassins running into each other or an impossibly large crowd at The Crucifixion.

One catch is that if there was any action that could make time travel impossible, and a transfinite future in which time travel is possible, with a similarly transfinite number of time-travelers, one of them will eventually do that very thing and block time travel for everyone permanently.

And I still like the central conceit of Niven's "Rotating Cylinders and the Possibility of Global Causality Violation".

Spoiler:

The universe itself hates time machines, and thus a series of increasingly implausible and catastrophic coincidences will ensure that none will be completed.

Niven also wrote:

GIVEN: That the universe of discourse permits both time travel and the changing of the past.
THEN: A time machine will not be invented in that universe.

For, if a time machine is invented in that universe, somebody will change the past of that universe. There is just too much future subsequent to the invention of a time machine: too many people with too many good motives for meddling with too many events occurring in too much of the past.

If we assume that there is no historical inertia, no Conservation of Events, then each change makes a whole new universe. Every trip into the past means that all the dice have to be thrown over again. Every least change changes all the history books, until by chance and endless change we reach a universe where there is no time machine invented, ever, by any species.

Then that universe would not change. (ed note: in other words, the universe will keep changing until it reaches a stable state, and that state is one where no time machines are invented)

Now assume that there is an inertia to history; that the past tends to remain unchanged; that probabilities change to protect the fabric of events. What is the simplest change in history that will protect the past from interference?

Right. No time machines!

NIVEN'S LAW: IF THE UNIVERSE OF DISCOURSE PERMITS THE POSSIBILITY OF TIME TRAVEL AND OF CHANGING THE PAST, THEN NO TIME MACHINE WILL BE INVENTED IN THAT UNIVERSE.

From THE THEORY AND PRACTICE OF TIME TRAVEL by Larry Niven (1971)

 

[Werner]

Worse: Consider the effect of time travel from the perspective of the points in time when the time machine departs or arrives. When the machine and its contents disappear, there is a huge loss of energy/mass and information; when it appears, there is a gain in both. Which contradicts some very basic laws of physics.

When a time machine departs it is replaced with an expanding wavefront of energy equal to its previous rest mass energy prior to departure, so it will be like a matter-antimatter explosion. When the time ship arrives it comes with an expanding wavefront of negative energy equal to but opposite from its rest mass, negative energy can take the form of an expanding gravitational wave that passes through objects.

 

[Straybow]

I got an idea for a time machine:


<<wormhole>>

People like to invoke wormholes. But wormholes big enough for material objects to enter would have force gradients that would atomize those material objects, much like the gravity gradient near a black hole.

 

[Werner]

People like to invoke wormholes. But wormholes big enough for material objects to enter would have force gradients that would atomize those material objects, much like the gravity gradient near a black hole.

Wormholes are theoretical objects, no one has been through actual one.

 

[whulorigan]

People like to invoke wormholes. But wormholes big enough for material objects to enter would have force gradients that would atomize those material objects, much like the gravity gradient near a black hole.

Wormholes are theoretical objects, no one has been through actual one.

Yes, but they are predicted and modeled by Theory (which is why they are Theoretical objects, and not merely speculative ones). As Theoretical objects they obey the laws and parameters inherent to the related Theory.

This is of course not to say that there are not other factors that might influence their behavior that we have not considered, due to a current lack of knowledge and understanding of the phenomenon, or of other factors that would impinge upon the behavior of the phenomenon.

Nevertheless, the very fact that we have a "Jump Drive" in Traveller (which also both defies current Theory and seems to be at least tangentially related to wormholes in some way) means that there is plenty of room for the "fiction" part of the term "Sci-Fi" to come to your rescue.

 

[Werner]

If you can pass through information, you can reconstruct a object on the other end regardless of the tidal forces, if you can send information back in time, you have a time machine, getting physical objects through is just a detail. The cosmic string is what you use to get one end of the wormhole into the past, and then you can send things through the wormhole. The Stargates in Stargate SG1 seem to operate by this principle, you don't just step through, you step through, dematerialize, the information is sent through then you rematerialize

 

[Straybow]

The whole dematerialize-rematerialize notion is the least scientific of all scifi, even beyond time travel. :CoW:

The material thing is, by it's very nature, the most compact form of information about the thing. Each cell is so ridiculously complex that a vast number of molecules in it (perhaps the majority) have yet to be analyzed. You can't analyze every cell and transmit that data (trillions of cells each greater than the sum of human knowledge) nearly instantaneously, much less process that data and reconstruct the whole (from what stock?) in a fraction of a second.

Just sayin' ...

 

[kilemall]

The whole dematerialize-rematerialize notion is the least scientific of all scifi, even beyond time travel. :CoW:

The material thing is, by it's very nature, the most compact form of information about the thing. Each cell is so ridiculously complex that a vast number of molecules in it (perhaps the majority) have yet to be analyzed. You can't analyze every cell and transmit that data (trillions of cells each greater than the sum of human knowledge) nearly instantaneously, much less process that data and reconstruct the whole (from what stock?) in a fraction of a second.

Just sayin' ...

I could have sworn the new local fiber optic offerings promised that sort of throughput.

 

[Werner]

You don't have to reproduce every subatomic particle! The important information for rebuilding a human being is at the cellular level, and that contains a good deal less information that the positioning and state of every single electron, proton, and neutron. You get the cells in the right positions with the right connections in the human brain and you can reproduce the person with all his thoughts, feelings, and memories, the rest of the person is not as important, all he needs is functioning limbs and organs, which nature takes care of according to our genetic code. Ever see a pair of identical twins? That is how nature does it, so basically we make a cellular copy of your brain and we clone the rest of your body, you will have a different set of finger prints, but who cares? For other objects you use a 3D printer and what GURPS calls a minifac, which is a miniature factory that assembles all the parts that you 3D print.

 

[Proneutron]

You don't have to reproduce every subatomic particle! The important information for rebuilding a human being is at the cellular level,

Big snip. It doesn't work for two main reasons. 1: E=MC2 (btw, if the ship ran low on energy/fuel just chuck a crew member into the dematerializer ...) and 2: when you separate every particle of a persons body they die. EVERY TIME. Otherwise all those ST deaths caused by injury would be reversible by just "beaning in" the missing/damaged body parts

 

[Grav_Moped]

Or just replicating them from the save file.

You did make a backup, didn't you?

 

[Condottiere]

Or cloned.

 

[Werner]

Big snip. It doesn't work for two main reasons. 1: E=MC2 (btw, if the ship ran low on energy/fuel just chuck a crew member into the dematerializer ...) and 2: when you separate every particle of a persons body they die. EVERY TIME. Otherwise all those ST deaths caused by injury would be reversible by just "beaning in" the missing/damaged body parts

Does a person have a soul or software? Battlestar Galactica raised that question, but it seems to me that souls are immaterial and so is information, how do you know the two aren't the same thing?

If you have the information to recreate someone's mind and the material and capability to rebuild him with, how do you know it isn't the same person, as far as the recreated person is concerned, he is that same person, as he has the same memories as the original, as far has he knows, his soul must have migrated from the old body to the new. You don't have to convert matter into energy and energy back into matter to recreate him, just transmit the information and use local atoms to reconstruct him, I am sure atoms were pretty much the same millions of years ago as they are today, if we could transmit information about ourselves into the past, we could rebuild ourselves in the past, we would wake up there with memories of the future.

 

[Proneutron]

If you have the information to recreate someone's mind and the material and capability to rebuild him with, how do you know it isn't the same person,

Not sure but the ORIGINAL person knows :rofl:

But anyway, E=MC2 prohibits that magic process that was started because of a low production budget. Take away transporters and replicators and it works much better.

 

[Straybow]

You don't have to reproduce every subatomic particle! The important information for rebuilding a human being is at the cellular level, and that contains a good deal less information that the positioning and state of every single electron, proton, and neutron. You get the cells in the right positions with the right connections in the human brain and you can reproduce the person with all his thoughts, feelings, and memories, the rest of the person is not as important, all he needs is functioning limbs and organs, which nature takes care of according to our genetic code. Ever see a pair of identical twins? That is how nature does it, so basically we make a cellular copy of your brain and we clone the rest of your body, you will have a different set of finger prints, but who cares? For other objects you use a 3D printer and what GURPS calls a minifac, which is a miniature factory that assembles all the parts that you 3D print.

That is (early to mid) 20th century thinking. Mechanical stuff could well do with cell templates when recreated. Bone, ligament/tendon, muscle, skin. Perhaps cells in liver, kidney, and some other organs would be nonspecific enough to go be template.

Cellular machinery is far more complex than envisioned even as recently as the 1980s. The state of cells, particularly neurons, could be highly dependent on the molecular stuff that we don't really understand. We don't have a good grasp on how neurons function as a network in the brain. For that you'd need to map all the molecules. That's the stage where the molecule is the simplest form of expressing the data.

But it doesn't matter. There still isn't a way to reconstruct a macroscopic object molecule by molecule in a span of seconds.

I do remember the scene from Fifth Element when they had little more than a small sample of flesh and they reconstructed her in a kind of cellular printer. That's space opera that doesn't take itself seriously.

 

[Nathan Brazil]

You don't have to reproduce every subatomic particle! The important information for rebuilding a human being is at the cellular level

To reproduce a human with the same genetic profile as Nathan Brazil, no problem. Grab that pound of flesh, find the DNA, disintegrate the unnecessary waste material, transmit. At the receiving end, go backwards medically as it were to determine the undifferentiated stem cells using the transmitted DNA as a blueprint, then apply some process to differentiate the cells. Cool you now have a new blank Nathan Brazil and given a chance his seed will infest the world. (its the season :devil

:coffeesip: But don't you have to scan the ENTIRE brain in some manner to get the Nathan Brazil neuron connections that generate/store memories? That way you get the specific Nathan Brazil whose love of Traveller, Dark Shadows and Industrial Music shapes him? Or you might get the one that likes My Little Pony instead. (Well the Kkree are close yes?:rofl