Also, the Z axis thing, where even if you could set off from cape Canaveral to arrive on the west coast of Mexico, you'd either be deep inside the earth, high up in the air or find yourself orbiting the earth. I imagine that even if they could solve all of the impossible problems, why would anyone want to go back to the days before Adventure Time, with terrible computers running really slow internet? To paraphrase LP Hartley, the past is another country- close our borders now!
I'm sorry to say this doesn't move me! These kind of gotcha explanations of fiction never engage with the actual premise.
All position in space and motion is relative to some frame of reference. What you're doing here is imagining the time traveller unmooring themselves from it all. But there is no absolute frame of reference, and even if there was, no science fiction author is imagining the time machine working that way. There are two common time travel machine concepts:
1. The machine moves between fixed points in space-time relative to the Earth (e.g. it appears to emerge in the same location each time).
2. The machine is also a teleporter and can move to any point in space and time (ancient Egypt, revolutionary America, Napoleonic France etc.).
I appreciate your comments, but I think you’re misapplying the frame of reference. The standard trope of time travel is applying the absolute frame of reference, assuming that the time traveler can change only one dimension, time, relative to the absolute. If we accept the theory of relativity, then the time traveler, detaches himself or herself from the motions of the Earth and solar system and their inertial frames of reference. This leads the time traveler to all kinds of consequences, most of which we can only guess within special relativity and can’t really test. What I sufficed to discuss in this highly simplified article was the loss of Earth’s inertial frame of reference and its most obvious consequence.
Is the time machine doing a time-hop (an "instantenous" coordinate change => your arguments apply), or a time-move over a continues space-time path? If it is really "moving continually" through the time coordinate at some accelerated pace and in the chosen direction, then I would expect some dragging force of the Earth mass on the machine while it works, keeping it in place on the surface.
In general when we take an idea from fiction and see that we can interpret it to have self-defeating ramifications (for example, those mathematical models of vampire propagation, or arguments about the impossible size of the ice wall in A Song of Ice and Fire), there are two possible responses:
1. We conclude that the author was mistaken about the conceivability of their idea and that the whole thing is absurd.
2. Because the way we're imagining it working can readily be debunked, but it works in the fiction, it must actually work in some other way than the way we were imagining it.
I can see #1, like your article, as a fun sort of exercise, but I think #2 is more creatively interesting and more properly engages with the fiction. Time travel obviously can't work by fixing someone to some absolute frame of reference (not least of all because there's no such thing!), for the reasons you've shown nice and clearly. So if we are to imagine it working, it must work in a different way.
The big problem with time travel is: would you have an effect on the future that has already occurred?
If no, then all is cool and maybe reverse time travel can exist. But that throws the effect of a butterfly flapping its wings a few extra beats millions of years ago out the window.
OTOH, if yes, then if there were reverse time travel, our present would be changing from second to second due to the changes the time traveler was creating by interacting with the past. Would we recognize these cascading changes? Or would we just have a vague feeling that something was different than it was a few moments ago?
But there is one solution that would allow reverse time travel w/o changing the future and that is if there were parallel realities. A reverse time traveler would essential cause a the creation of a new reality fork, where all the changes made by the time traveler(s) get encapsulated. This would protect the existing reality that the time traveler originated from from being rewritten.
Given that our metaverse may be infinite, why couldn't experience realities also not be infinite, stacked one next to another as necessary to permit reverse time travel?
"Before you start your career as a chronic argonaut, you should remember one very important fact. Even if time is the fourth dimension, you cannot forget about the first three dimensions. Moving through time also means moving through space."
----
C'mon! Any self-respecting genius able to build a time machine would also include a computer that would do all the calculations necessary to drop the traveler into an empty space in the location of their choice in the past (you wouldn't want to materialize where a brick wall exists).
I agree with your assessment of time travel simply because this was the premise of the ‘time bomb’ in the Strontium Dog comics. Although a pre-set time bomb was used by Johnny Alpha on himself and Wulf Sternhammer as an escape device to get somewhere else. But the ‘bomb’ use was to throw one at an enemy/enemies who would be sent back in time a few seconds, but not space. So they would be left in space gasping for air.
Would it not be possible to calculate your move in all four directions? If I know where I’m standing will be X million miles away in a year could that not be part of the time travel equation?
Also, the Z axis thing, where even if you could set off from cape Canaveral to arrive on the west coast of Mexico, you'd either be deep inside the earth, high up in the air or find yourself orbiting the earth. I imagine that even if they could solve all of the impossible problems, why would anyone want to go back to the days before Adventure Time, with terrible computers running really slow internet? To paraphrase LP Hartley, the past is another country- close our borders now!
I'm sorry to say this doesn't move me! These kind of gotcha explanations of fiction never engage with the actual premise.
All position in space and motion is relative to some frame of reference. What you're doing here is imagining the time traveller unmooring themselves from it all. But there is no absolute frame of reference, and even if there was, no science fiction author is imagining the time machine working that way. There are two common time travel machine concepts:
1. The machine moves between fixed points in space-time relative to the Earth (e.g. it appears to emerge in the same location each time).
2. The machine is also a teleporter and can move to any point in space and time (ancient Egypt, revolutionary America, Napoleonic France etc.).
I appreciate your comments, but I think you’re misapplying the frame of reference. The standard trope of time travel is applying the absolute frame of reference, assuming that the time traveler can change only one dimension, time, relative to the absolute. If we accept the theory of relativity, then the time traveler, detaches himself or herself from the motions of the Earth and solar system and their inertial frames of reference. This leads the time traveler to all kinds of consequences, most of which we can only guess within special relativity and can’t really test. What I sufficed to discuss in this highly simplified article was the loss of Earth’s inertial frame of reference and its most obvious consequence.
Is the time machine doing a time-hop (an "instantenous" coordinate change => your arguments apply), or a time-move over a continues space-time path? If it is really "moving continually" through the time coordinate at some accelerated pace and in the chosen direction, then I would expect some dragging force of the Earth mass on the machine while it works, keeping it in place on the surface.
In general when we take an idea from fiction and see that we can interpret it to have self-defeating ramifications (for example, those mathematical models of vampire propagation, or arguments about the impossible size of the ice wall in A Song of Ice and Fire), there are two possible responses:
1. We conclude that the author was mistaken about the conceivability of their idea and that the whole thing is absurd.
2. Because the way we're imagining it working can readily be debunked, but it works in the fiction, it must actually work in some other way than the way we were imagining it.
I can see #1, like your article, as a fun sort of exercise, but I think #2 is more creatively interesting and more properly engages with the fiction. Time travel obviously can't work by fixing someone to some absolute frame of reference (not least of all because there's no such thing!), for the reasons you've shown nice and clearly. So if we are to imagine it working, it must work in a different way.
I actually wrote about something like this
https://substack.com/@ganiruofalltrades/note/p-209933695?r=78uziu
The big problem with time travel is: would you have an effect on the future that has already occurred?
If no, then all is cool and maybe reverse time travel can exist. But that throws the effect of a butterfly flapping its wings a few extra beats millions of years ago out the window.
OTOH, if yes, then if there were reverse time travel, our present would be changing from second to second due to the changes the time traveler was creating by interacting with the past. Would we recognize these cascading changes? Or would we just have a vague feeling that something was different than it was a few moments ago?
But there is one solution that would allow reverse time travel w/o changing the future and that is if there were parallel realities. A reverse time traveler would essential cause a the creation of a new reality fork, where all the changes made by the time traveler(s) get encapsulated. This would protect the existing reality that the time traveler originated from from being rewritten.
Given that our metaverse may be infinite, why couldn't experience realities also not be infinite, stacked one next to another as necessary to permit reverse time travel?
"Before you start your career as a chronic argonaut, you should remember one very important fact. Even if time is the fourth dimension, you cannot forget about the first three dimensions. Moving through time also means moving through space."
----
C'mon! Any self-respecting genius able to build a time machine would also include a computer that would do all the calculations necessary to drop the traveler into an empty space in the location of their choice in the past (you wouldn't want to materialize where a brick wall exists).
This is how SF works. 😁
Doing the calculations is one thing; being able to defy the laws of physics is a bigger challenge.
I agree with your assessment of time travel simply because this was the premise of the ‘time bomb’ in the Strontium Dog comics. Although a pre-set time bomb was used by Johnny Alpha on himself and Wulf Sternhammer as an escape device to get somewhere else. But the ‘bomb’ use was to throw one at an enemy/enemies who would be sent back in time a few seconds, but not space. So they would be left in space gasping for air.
Most "time machined" also include a way to travel in space such as warp drive.
Would it not be possible to calculate your move in all four directions? If I know where I’m standing will be X million miles away in a year could that not be part of the time travel equation?