Not only is the earth never in the same spot, the solar system it's never in the same spot either. Even our galaxy is moving.
so would it be accurate to say that if one were to take a frame of reference on a large scale, say, the absolute centre of the universe (I know, but bear with me on this one), it's also fairly impossible to travel back in space as well as time, seeing as by the time it takes you to take a step back to your original position, the earth has already moved enough that you are no longer there relative to your reference?
I'm not sure "an absolute reference frame" exists. But, in your scenario they'd have to lead the shot so to speak. And jump in behind where they want to be.
"It's like hitting a bullet...with another bullet...while riding a horse...blindfolded."
And also any future position may be dependent on many variables that might be different each jump. If you were to go back in the past, the future location may be off greatly; just by going back may have altered the future location, insert multiverse theory etc
You'd almost need to somehow communicate back to or do some kind of survey or probe of the target space time coordinates and confirm somehow they are what/where you think they are, and lock in to them before actually doing the jump. Sounds impossible lol
do some kind of survey or probe of the target space time coordinates and confirm somehow they are what/where you think they are
That's what the Spice is for!
Time and space are pretty much linked so if you travel in time you can travel in spacetime :)
Yeah, but to my knowledge, you can only go forwards in time.
What you can do, is go forwards at a slower speed. So, if you sat yourself in a spaceship and accelerated to e.g. 10% of the speed of light, you might get out after what you perceive as a few years and find yourself in the year 2200 (I did not do the math), but you cannot go back from there.
Causal chains always have to follow causality. They can just do so less quickly, because, as far as my current understanding goes, the speed of light is actually the speed of causality.
(Sorry to bonk you with so much physics. I know that initial statement could have also come from someone who's never heard of the theory of relativity...)
The thing is, a time traveling device would be like the one on Futurama. It just makes time flow at different rates. What people generally think of is a time teleport. And due to the nature of spacetime, a time teleport is indistinguishable from a space teleport. So any teleport should require precise spacetime coordinates, and n9t jist either space or time coordinates.
Another interesting thing about futurama‘s time travel is that instead of going backwards in time, they kept going forward until another Big Bang happened, creating a universe identical to their old one. Then they were able to just keep going forward until they reached when they left
I think it's more correct to say that we don't know how to travel in the other direction on the time axis. It could also simply be our perception of time only works unidirectionally.
From a mathematics point of view, nothing is preventing going backwards in time... We simply don't perceive time that way.
Practically, this does nothing for us.
I don’t remember the name of the novel, so somebody help me with this. The concept is basically that scientists invent time travel, but use it as a teleportation device instead. Set the machine by a few seconds, you teleport the distance covered by the Earth during that time. They even use the technique to plan for an assasination of Kim Jong Un. Loved that one. Some innovative sequences using the ‘time machine’.
Edit: Found it. It's actually two books (original and sequel).
Split Second - https://www.goodreads.com/book/show/26216031-split-second
and
Time Frame - https://www.goodreads.com/book/show/37946554-time-frame
The first book takes its time revealing the 'time travel', but the second book dives head first into using the technology proficiently.
Accidentally read the second book thinking it was a stand alone. The story still held up so i made it half the book before i realized my mistake
It’s actually marketed as a standalone sequel, so you weren’t too far off. Plus I think the first one was more of an action thriller than about this invention. I actually don’t remember much from the first one. Most of what I remember is from the second one.
Same spot relative to what? What object do time machines use as a reference for their coordinates? It would make sense to be Earth, so it would be in the same spot all the time.
Weeeeell, not exactly.
It is true that things are all relative to each other. But think about it this was, if you fly out in a Starship in one direction for a light year, then turn around exactly 180 degrees and fly back, you wouldn't arrive back at earth, right? Mainly because things are accelerating due to gravity. And acceleration breaks symmetry.
It would of course depend on how time travel works, but since time and space are linked, it wouldn't be unreasonable to assume that you follow the same trajectory in space as you move through time. But that would be a straight line in the space+time dimensions still. Think of the paths in Minkowski diagrams.
Well, I am traveling forward in time in home made Time Machine with the speed of one second per second. I do not see any problem you are describing. Now I just need to add the reverse, but I do not expect any issues of this kind either.
A "sit on earth and watch things happen in reverse", like the movie The Time Machine? (I always wondered what everyone else thought of that.) Or was there another thought?
And your remains will eventually fly through space, too. Only with a planet called Earth around it.
In this case, it makes sense to time travel from space and land on a planet upon arrival. Maybe all UFOs are just time travellers after all?🤔
This is why I think time travel will require both an entry and an exit portal, though it’d be through the same device. You’d walk in the portal at one point in time and space, then walk out of the exact same portal at another point in time and space. You’d only be able to travel between points where that time device exists in time and space, you’re using the same portal to travel to a different time in its existence. So no traveling back to the time of dinosaurs or the beginning of time or going to any point past when the portal no longer exists anymore. It’d solve the problem of having to deal with galaxies/stars/planets moving through space and would help mitigate some paradoxes, though not all and maybe even create others.
Calculations of the movement of celestial bodies is pretty accurate though. Figuring out where the earth was in the past is the simple part of time travel. Additionally you could just combine a time machine with a space ship and return to space nearby where the planet would be and then have a lander module or something just in case.
Exactly, though there still is a possibility of exiting inside another celestial body, which is a whole another can of worms
If I recall correctly that was the premise on “Contact”, where Jody Foster asked her father what was that thing that brought her there and he stated he didn’t know, that they were left there by something else (the wormhole thingy). Sorry for all the nonspecifics and all.
Exactly. An anchor in space is required for time travel. One variable has to be constant at least.
Weak premise considering the principles of relativity, and how our current understanding of time travel is basically rooted in SPACE-time.
I read that ages ago. Back in high school, in fact (I'm 46). I don't remember it except the chapter where time is a flock of birds that you have to try to catch to stay youthful. The children can catch them but always let them go and the adults can never catch them.
Hey we are roughly the same age. I also read it in high school. Cheers 😁🍻
The one that stuck with me was the story about time getting slower the faster people moved. So everyone built their houses on rails and tried to keep moving as fast as possible just to have a few extra moments of time.
Absolutely loved that book and I can see why you posted this question. I often wonder the same.
I remember it was in the new books section of the school library and I was attracted to it immediately and spent the day reading it instead of paying attention in my classes. I need to read it again. Thanks for bringing it up!
I always assumed that teleportation would need to also be present for time travel. Clearly, just an assumption.
It would never reach it again because the solar system itself is moving and also the milky way
Semi-relevant Tom Scott (actually about teleportation, but covers many of the same problems)
