Time travel doesn't work unless you also have teleportation. If you travel to the past/future, Earth will be in a different position in its orbit, and you'll die in space.

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Submitted ⁨⁨1⁩ ⁨day⁩ ago⁩ by ⁨Balerion6@lemmy.world⁩ to ⁨showerthoughts@lemmy.world⁩

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TheLeadenSea@sh.itjust.works ⁨1⁩ ⁨day⁩ ago
What sort of universal reference frame do you seem to be assuming? All location is relative to other things, and keeping your location relative to, say, the Earth would be a lot more convenient that making it relative to some arbitrary star or something.

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- TrickDacy@lemmy.world ⁨1⁩ ⁨day⁩ ago
  Op thinks the universe is built with some inherently absolute positioning method. Thanks for writing this
  
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- half_built_pyramids@lemmy.world ⁨1⁩ ⁨day⁩ ago
  Use the time and space machine on a ruler and send it back in time a pico second, then a millisecond, then a thousand, then a second, then a minute. You just have to calibrate with measurements first.
  
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- TommySoda@lemmy.world ⁨1⁩ ⁨day⁩ ago
  But if you’re in a moving car and “pop” back a few seconds while the car doesn’t you won’t be in the car anymore. If it worked more like rewinding a video you wouldn’t need to do much, but I’m assuming OP means literally going “poof” and now you’re back in time. If that’s the case, you would still need to know how Earth is moving through spacetime. If you don’t know your relativistic relationship to the Earth and every other object in the universe then how would you know where you are or your own relativity compared to the Earth?
  
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  - Dave@lemmy.nz ⁨1⁩ ⁨day⁩ ago
    Their point is that (as per relatively), all movement is relative to something. So if the earth moved away then you must be measuring in relation to some other reference point. There is no absolute positioning system. So when you say the earth is moving, what is it moving in relation to? And why did you pick that reference point instead of having a time machine that uses earth itself as a reference point?
    
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  - 7uWqKj@lemmy.world ⁨1⁩ ⁨day⁩ ago
    Exactly, and due to earth’s rotation you don’t even need the car.
    
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- fubbernuckin@lemmy.dbzer0.com ⁨1⁩ ⁨day⁩ ago
  I’m using the microwave background as a reference
  
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  - daniskarma@lemmy.dbzer0.com ⁨23⁩ ⁨hours⁩ ago
    I tried, but then it started blinking.
    
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  - kryptonianCodeMonkey@lemmy.world ⁨20⁩ ⁨hours⁩ ago
    The microwave background is like a rainbow. When you move, it appears to move. You’re always at the “center” of it.
    
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  - TheLeadenSea@sh.itjust.works ⁨1⁩ ⁨day⁩ ago
    Lol, that’s omnipresent
    
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Bwaz@lemmy.world ⁨16⁩ ⁨hours⁩ ago
In a different position relative to what?

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- 01189998819991197253@infosec.pub ⁨15⁩ ⁨hours⁩ ago
  Relative to space
  
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  - Bwaz@lemmy.world ⁨13⁩ ⁨hours⁩ ago
    What point in space is the reference, where other things are placed relative to?
    
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Fetus@lemmy.world ⁨1⁩ ⁨day⁩ ago
I get that people just refer to them as time machines, but they’re actually space-time vehicles.

Before your first journey, you calibrate it to a reference point (mine already had Earth mapped out, with a gravity well depth monitor as a fail-safe) so that you lock your target coordinates in space and time.

But no, it’s not teleportation. You’re still just travelling to your destination, you just get there as quick as you want and without the need to be disintegrated.

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Fleur_@aussie.zone ⁨8⁩ ⁨hours⁩ ago
Alternatively teleportation doesn’t work unless you also have time travel

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kryptonianCodeMonkey@lemmy.world ⁨21⁩ ⁨hours⁩ ago
Space and time are the same thing. Spacetime. Time travel would necessarily also by teleportation if you are traveling instantaneously through spacetime. Unless of course your travel is continuous like it is currently for all of us, just sped up, slowed down or reversed.

Also there is n9 objective point of reference for location in the universe, only relative points of reference. In other words, you are always some distance in some direction from some thing. But you never have objective stable coordinates relative to the universe itself. Tere is no “center” or other fixed point of the universe. So the earth is moving, yes, but only relative to other independent celestial bodies. And those bodies are moving, too, relative to other bodies. Their movement is always relative to a non-absolute frame of reference. No movement is objective to the universe, it’s all relative.

So it would be illogical to expect the earth to have moved X miles away in Y direction if you teleported one second into the past/future because that would presuppose that your location was objective and absolute in the universe at the point of time traveling and the earth moved relative to your absolute location. It would break known physics if that were the case, as much as time travel itself would.

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- mechoman444@lemmy.world ⁨19⁩ ⁨hours⁩ ago
  🤔
  
  If only there was some kind of theory that could explain relativity.
  
  Especially in large celestial objects.
  
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01189998819991197253@infosec.pub ⁨15⁩ ⁨hours⁩ ago
Space is full of time travelers that forgot to include the Zed access into their calculations.

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- toynbee@lemmy.world ⁨12⁩ ⁨hours⁩ ago
  Zed access sounds a lot cooler and more scifi than z axis.
  
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  - 01189998819991197253@infosec.pub ⁨15⁩ ⁨minutes⁩ ago
    Hahahahaha!!! Oh, man. Speech to text did not do me well earlier hahahahah
    
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Durandal@lemmy.today ⁨1⁩ ⁨day⁩ ago
You just need to maintain a relationship between Time And Relative Dimension In Space. 🟦

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- Simulation6@sopuli.xyz ⁨1⁩ ⁨day⁩ ago
  – Time And Relative Dimension In Space
  
  or TARDIS for short?
  
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Kolanaki@pawb.social ⁨1⁩ ⁨day⁩ ago
I think it might depend on how the time travel is achieved. We all assume you’re just instantly pooped out in your destination time but if you have to actually travel through time, it might be like just putting everything in reverse, and so you’d move alog with the earth as you move backwards through some kind of time tunnel.

Think Donnie Darko and not Looper.

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- gedaliyah@lemmy.world ⁨1⁩ ⁨day⁩ ago
  This was the thing in the HG Wells version that always got me. The machine always exists for the intervening time. I feel like that would be very disruptive to the civilizations that encounter it.
  
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  - Death_Equity@lemmy.world ⁨1⁩ ⁨day⁩ ago
    I think the distortion field sort of addresses that.
    
    The machine would be hidden within the field and invisible and intangible. That of course presents the problem of ending up in a wall and also would likely mean that you would end up in the air if the ground erodes or in the ground if sediment is deposited.
    
    The alternative is either there is a mysterious bubble that becomes a scientific curiosity or there is the machine with someone frozen inside it that is destroyed by people being people. Both have their own fun little narratives to explore.
    
    That is all based on the assumption that the machine travels forward in time through localized dilation instead of folding spacetime, which would mean it has two methods to travel depending on it going forwards or backwards in time.
    
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dwraf_of_ignorance@programming.dev ⁨1⁩ ⁨day⁩ ago
Just want to leave it hereImage

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- cm0002@lemmy.world ⁨1⁩ ⁨day⁩ ago
  I…I need the template for that meme :o
  
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  - Ofiuco@piefed.ca ⁨1⁩ ⁨day⁩ ago
    Did you get it?
    I kind of want it too for... Reasons... Stupid stupid reasons.
    
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  - ByteJunk@lemmy.world ⁨1⁩ ⁨day⁩ ago
    For science?
    
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RagingSnarkasm@lemmy.world ⁨1⁩ ⁨day⁩ ago
Tell me you didn’t pay attention in Spatial Distortion as Applied to Time Dilation class without telling me you didn’t pay attention in Spatial Distortion as Applied to Time Dilation class.

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LovableSidekick@lemmy.world ⁨20⁩ ⁨hours⁩ ago
Teleportation or having your time machine also be a spaceship so you can land.

Image

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- jj4211@lemmy.world ⁨17⁩ ⁨hours⁩ ago
  Or, in that case, stealing someone else’s spaceship time machine
  
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- 01189998819991197253@infosec.pub ⁨15⁩ ⁨hours⁩ ago
  
  Never go in against an Australian when death is on the line!
  
  One of the best charactera
  
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samus12345@sh.itjust.works ⁨21⁩ ⁨hours⁩ ago
That’s correct. But if you’ve figured out how to travel through time, traveling through space should be easy.

Also, be sure to wear a hazard suit so you don’t die from any ancient/future diseases your body has no protection from.

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TabbsTheBat@pawb.social ⁨1⁩ ⁨day⁩ ago
What if it works by reversing/fastforwarding time outside while preserving things within the time machine? Then as long as the time machine is grounded to the earth it would move with it

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- KoboldCoterie@pawb.social ⁨1⁩ ⁨day⁩ ago
  So, Primer, then? Where you turn on the time machine at the point you want to return to, and when you get into it in the future you’re returned to that point?
  
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otacon239@lemmy.world ⁨1⁩ ⁨day⁩ ago
That’s why I always liked approaches that use a physical machine that has to stay in one place for an extended period of time. Quantum Break’s hard sci-fi approach to this was fascinating and kept making me reconsider how the time loop worked. Highly recommended for time loop nerds like me.

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- agamemnonymous@sh.itjust.works ⁨18⁩ ⁨hours⁩ ago
  I’m convinced that if there’s a way to build a time machine, it’ll probably work like Primer.
  
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jordanlund@lemmy.world ⁨1⁩ ⁨day⁩ ago
Forget the orbit… remember the song…

genius.com/Monty-python-the-galaxy-song-lyrics

“Just remember that you’re standing on a planet that’s evolving
And revolving
at 900 miles an hour.
It’s orbiting at 19 miles a second,
so it’s reckoned,
The sun that is the source of all our power.
Now the sun, and you and me,
and all the stars that we can see,
Are moving at a million miles a day,
In the outer spiral arm,
at 40,000 miles an hour,
Of a galaxy we call the Milky Way.”

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VicksVaporBBQrub@sh.itjust.works ⁨1⁩ ⁨day⁩ ago
A wormhole type time machine would leave the travel points A and B physically independent of each other. This opens up the option to change destinations… step in at New York, exit in San Francisco.

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- 7uWqKj@lemmy.world ⁨1⁩ ⁨day⁩ ago
  Due to the energies involved, creating a wormhole between two cities would probably leave you with a wormhole and no cities.
  
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  - rikudou@lemmings.world ⁨1⁩ ⁨day⁩ ago
    Those are just small issues that will be solved after few tries.
    
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realitista@lemmy.world ⁨23⁩ ⁨hours⁩ ago
Maybe if you timed it juuuuuust right you could land somewhere on the planet as it orbits the sun? I mean I guess it depends on how you determine absolute location in the universe. Is that even possible with the universe constantly expanding?

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- massacre@lemmy.world ⁨21⁩ ⁨hours⁩ ago
  Nope, not possible. The solar system itself is moving as is the galaxy… it’s useful to think of Earth’s orbit as spiraling around the sun in the direction our star is traveling. So 1 orbit later we have not come to the same location.
  
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  - realitista@lemmy.world ⁨20⁩ ⁨hours⁩ ago
    But moving relative go what?
    
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MTK@lemmy.world ⁨1⁩ ⁨day⁩ ago
Being sci-fi it can be explained with ^Q^ ~u~ ^a^ ~n~ ^t^ ~u~ ^m^ ^E^ ~n~ ^t^ ~a~ ^n^ ~g~ ^l^ ~e~ ^m^ ~e~ ^n^ ~t~

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ns1@feddit.uk ⁨1⁩ ⁨day⁩ ago
This is interesting because the most “realistic” (i.e. still not realistic) depictions of time travel in fiction involve travelling through a singularity or wormhole. So you probably have to be in space to start with, but also both ends of the wormhole have mass so they can be orbiting a planet or star and stay within a stable distance of it. It solves this particular problem (just leaving the other usual problem of causality!) It also proves your point since it does allow travelling in space, in fact it allows travelling faster than light.

I think the converse is true as well, that if faster than light travel is possible then time travel must be possible, at least if you take relativity at face value. As others have pointed out there’s no universal reference frame, and for any journey that is faster than light in one reference frame, there is another frame in which the journey goes backwards in time.

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takeda@lemmy.dbzer0.com ⁨1⁩ ⁨day⁩ ago
That’s why they used Delorean.

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rowinxavier@lemmy.world ⁨1⁩ ⁨day⁩ ago
Yep, and not to mention the position of our solar system in the Milky Way or our galaxy in the local cluster. In fact, without a specific reference frame you would have to make corrections very rapidly for even a tiny jump in time.

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- toast@retrolemmy.com ⁨1⁩ ⁨day⁩ ago
  Depends on how time travel works. I mean, within the next 24 hours I plan to travel to tomorrow. I’m not going to be taking any of that into account.
  
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- Hugin@lemmy.world ⁨1⁩ ⁨day⁩ ago
  There was a not very good TV show Seven Days that used this well. They had a time machine that could go back in time seven days. The pilot had to fly the machine chasing the earth as he traveled back in time.
  
  He would usually end up crashing it somewhere and have to find a phone to call for pickup.
  
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  - rowinxavier@lemmy.world ⁨15⁩ ⁨hours⁩ ago
    Yep, and he had to also solve the problem of the week given everything they could figure out in the 7 days following it happening. A cool set of limitations for the writers, the execution was a little sloppy, but overall a cool idea.
    
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bvoigtlaender@feddit.org ⁨1⁩ ⁨day⁩ ago
All my childhood i was scared about being stuck in a building that was there back then. If i knew that was my smallest problem i would have scratched that idea long ago.

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