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submitted 7 months ago* (last edited 7 months ago) by fossilesque@mander.xyz to c/science_memes@mander.xyz

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[-] GoodEye8@lemm.ee 15 points 6 months ago* (last edited 6 months ago)

I think that's the joke. Media presents time travel as just inputting the date and off you go, but really you need to input time AND space because the two are interconnected.

Of course we could just imagine that all time machines somehow calculate the space itself just by knowing the current spacetime and the inputted time, but now we're giving writers too much benefit of doubt. In most cases time travel is used as plot device and very little thought is given to how it could work.

And an interesting sidenote. This also means that teleportation is a special case of time travel and if you've solved time travel you've probably also solved teleportation.

[-] Schadrach@lemmy.sdf.org 3 points 6 months ago

Media presents time travel as just inputting the date and off you go, but really you need to input time AND space because the two are interconnected.

Alternately since we're Earthlings, someone designing a time machine might think it's a good idea to automatically calculate the location using the Earth as a reference point because that's likely to be the most common use case and doing so would prevent you from dying to the void of space if you make a tiny math error. At which point you would just need to input the destination time if the target is the same location relative to Earth.

[-] nilloc@discuss.tchncs.de 1 points 6 months ago

Or maybe the time travel happens by warping space in the first place (since you need to somehow overcome the speed of light problems anyway). Seems like a good job for a wormhole if someone wanted to write around the space/time/motion rules.

[-] Schadrach@lemmy.sdf.org 1 points 6 months ago

Wouldn't matter, because the problem isn't about space or motion, but about position. If you jump backwards in time but your position in the universe doesn't change then you are probably no longer on earth because the Earth moves about the sun, etc. To land somewhere meaningful, you'd have to calculate the target location relative to some reference point with a predictable location and as Earthlings we'd probably pick the Earth itself unless this is a time traveling spacecraft.