FTL, Relativity and Causality - Spawn Of Magic Thread

[alex_greene]

Behold, the Spawn of Magic & Sci Fi, from where the discussion of causality, relativity and the impossibility of faster than light travel has just been spawned to give those on the other thread room to breathe about other, more germane, topics on that thread.

Please continue the discussion of FTL from that other thread here.

 

[simonh]

There was an old lady called Wright
who could travel much faster than light.
She departed one day
in a relative way
and returned on the previous night.

Simon Hibbs

 

[Tom Kalbfus]

One way to do Time Travel is to go the Holodeck route, you just recreate the time period virtually in an arbitrarily powerful computer and you alter anything you like without consequence, this is identical to the many Universes theory of time travel, if you go back in time and change history, you spawn a separate universe.

 

[Rick]

One way to do Time Travel is to go the Holodeck route, you just recreate the time period virtually in an arbitrarily powerful computer and you alter anything you like without consequence, this is identical to the many Universes theory of time travel, if you go back in time and change history, you spawn a separate universe.

One of the multiverse/time travel theories I thought was more plausible (heh) was put forward as; because paradoxes are impossible, you could never travel back into your own universes past. The very act of travelling back in time would shunt you across to a parallel universe where you could do whatever you wanted with no consequence to your existence. Unfortunately, this might well mean that there was no way of getting back to your starting point universe.

 

[Tom Kalbfus]

One way to do Time Travel is to go the Holodeck route, you just recreate the time period virtually in an arbitrarily powerful computer and you alter anything you like without consequence, this is identical to the many Universes theory of time travel, if you go back in time and change history, you spawn a separate universe.

One of the multiverse/time travel theories I thought was more plausible (heh) was put forward as; because paradoxes are impossible, you could never travel back into your own universes past. The very act of travelling back in time would shunt you across to a parallel universe where you could do whatever you wanted with no consequence to your existence. Unfortunately, this might well mean that there was no way of getting back to your starting point universe.

Depends on how you travel back in time. If you travel back in time using a wormhole, then the Universe splits and the wormhole connects two universes, this is functionally equivalent to having a Matrix "Time Machine". Remember the movie the Matrix? Characters started out in what they though was the present and they ended up in the "Future" but actually no time travel actually occurred, they could go back into the Matrix and do whatever they pleased without any consequences to their existence, because it only appears they went back in time.

In My other thread, The Niven Ring, part of it was a virtual matrix machine for simulating other times and places either historical or imaginary. Now just think, a Ringworld has the surface area of 3 million Earths. The hard part about building a ringworld is to make it strong enough so that when spun for centrifugal "gravity" it doesn't fly apart, but if you just want the virtual matrix part without the centrifugal force, just build one that spins at orbital velocity around the Sun, you ca use ordinary material to build it then, and just fashion it into a giant computer. You still have 3 million times Earth's surface area. That could be your virtual Matrix "Time Machine" Each Earth could be one of 3 million Earth years of history or prehistory. Start with one, then have a character in it "go back in time" and change history, so now the computer simulates two Earths, one is the one he left and the other is the one he traveled to and altered the history of. Now this time traveler can make 3 million trips back in time with this machine. This is the easiest sort of "Time Machine" one can make, as one doesn't actually have to bend or warp space or exceed the speed of light, you just need an arbitrarily powerful computer to run the simulation of whatever Earth era you want to pretend to visit.

 

[Rick]

But not a time machine. You would not be going back to a previous time; you would be virtually experiencing a time based on the guesses and (flimsy) archaeological evidence of the present day (or future present day) and interpreted through a modern perspective. This might be ok for a theme park type ride, but it isn't time travel.

 

[Tom Kalbfus]

But not a time machine. You would not be going back to a previous time; you would be virtually experiencing a time based on the guesses and (flimsy) archaeological evidence of the present day (or future present day) and interpreted through a modern perspective. This might be ok for a theme park type ride, but it isn't time travel.

But how are you to know the difference? If the simulation is based on flimsy archeological evidence that evidence is all you got as well to compare it with. Since there is a lack of data, the producers of the simulation have to make things up to fill in the gaps of their information, they also have to make sure that the made up stuff fits into the gaps in their knowledge, meaning that the made up stuff is plausible and could have been true, if all the information within the simulation is consistent with known facts, it would be hard to tell from actual time travel it is a good simulation. The only way to tell if its not is if new information turns up concerning the past that contradicts what the simulation has. As for the virtual inhabitants of the simulation, they don't know that their history is wrong. I use the "Virtual Time Machine" idea to explain how my various characters end up in my Ringworld setting, I don't bother with time machines, this works just as well for my story purposes.

The advantage here is you can interact with the simulation and even change history and all it does is make the simulation more wrong, it doesn't create a time paradox, as its not actual time travel!