I was surprised when I read the OG time machine story by Jules Verne and this was a main plot point, and only later stories hand-waived it. You'd think it was something from later analysis of the idea. Almost like that Verne dude was clever.
this post was submitted on 13 Mar 2025
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Clark Ashton Smith wrote a similar short story where the inventor failed to take it into account. Upon realizing his mistake he decided to just wait for another planet to reach him, turning his time machine into a spaceship.
That's actually a fascinating idea. All interstellar travel is based on the movements of the planets through space time. I bet it alternates between being technically faster and slower than FTL travel since you may have to wait for a time when your destination to pass into the planets past location.
Wow that's a fun thought hole. Constraint certainly breeds creativity!
Classic sci-fi slaps hard
that's why you build it like a spaceship 🤷 ez
I hear police boxes and phones booths are popular as well.
Position isn't absolute so if this happens this means you knowingly made the time machine memorize position relative to e.g. the sun rather than the earth.
Or relative to the galactic center. That would put you even further off.
incorrect, that is not what this means. They could have forgotten about the position setting all together. Also why the suns position? it is also moving and non absolute, just like earths. Makes no difference in this meme
All of space is moving, you need to fix a reference point, there's nothing to stop you making it earth
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They could have forgotten about the position setting all together.
You're assuming that the time machine would just change the time and keep the position but there is no absolute reference frame, so the time machine should use some reference frame in which it keeps the position constant. It would then be common sense to have the time machine keep the position relative to the earth. Anything else would be pretty dumb, unless you want to use your time machine also for space travel to other planets.
why the suns position
That was just an example. It's either the sun or the center of our galaxy, or some other reference point so if it wasn't the earth then the sun is the next most logical option.
What you're describing is a machine which moves both in time and space. A machine which only moves in time would result in this meme no matter how you twist it.
That isn't possible. Time is as part of space as the other dimensions. Time is distorted by mass, just like space.
You can't move "purely on the Y axis" any more than you can move "purely on the time axis", or vice versa.
Off topic: Why is it a new idea that the observed motion of the universe around us is affected by "faster time" in denser areas of space? Why is that not blindingly obvious? Bwuh?
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This is not how general relativity works at all. If your coordinates are set to a spot on Earth (or some spot relative to Earth), you will appear at that same point. Spacetime exhibits something called diffeomorphism covariance which is a fancy way of saying you'd have to go out of your way in the dumbest way possible to get this outcome.
I remember reading about this concept as a kid in a short story Neal Shusterman wrote called Same Time, Next Year. Blew my mind
If space is always expanding, I’d really like to know if a time traveler would experience issues existing in a universe where the space between atoms is different from the one they left.
They are not, that would require changes in the strong force.
They wouldn't; the expansion of space isn't strong enough to change the distance between atoms; the force holding them together overcomes it.
I was under the impression that gravity was a constant force keeping the atoms closer together
More importantly it's the electromagnetic force that keeps atoms together. Gravity only keeps planets and stars together and also solar systems and galaxies, but in ordinary objects it's totally negligible.
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One way to resolve this is to have some kind of multiverse theory where you don't travel back in time to your universe, but to a narrow slection of parallel universes that are also shifted slightly so that it spits you out in an analogous location to your initial departure.
I know we're in a meme community but this did get me thinking... Not only is the Earth spinning but it's also in an orbit around the Sun which is also orbiting around the center of the Milky Way which is moving through space relative to other galaxies and so on.
Do we have enough information to calculate a position in space in the future for Earth without a fixed reference other than current point?
That's what einstein said. There is no fixed reference frame, but only relative ones. Every "inertial"(meaning, motion without any external force) frame of reference is equally valid as any other inertial frame movibg with respect to it.
But for sure we can tell earth's orbit is not inertial since circular motion occur, which is due to external force of gravity.
Edit:typo
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There is not central point in the universe, and no way to calculate a position. Everything is relatove
This is why Doctor Who has a time and space machine. Also because the BBC didn’t have the effects budget to show him flying around.
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This blew my mind. All those movies!
So, Back to the Future's a bunch of bullshit?!
It's possible to assume that the professor did the math.
But yeah any time machine would also basically have to have space travel built in to compensate.
They knew that when they wrote Dr Who (IE the time travel machine is called a TARDIS (Time and Relative Dimension in Space).
Nah, this thing with the planet moving under you is stupid because it assumes a fixed reference frame which is not a thing in our universe. Any movement is always relative to something. You can't just "stay in place". Having the Earth move from under you is very arbitrary.
Yeah, these jokes always assume a jump back in time, not some sort of rewinding for just the traveler.
Even if you assume any frame is valid, you have to pick inertial frames. So even if you travel few days, you will be off from earths orbit into space since earth is in circular motion which is acceletared
There's a ton of issues with time travel. That could be one, but most fictional time-travel devices can be said to accommodate for the difference in distance. It would just be boring to explain on-screen.
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You've got to entangle the same machine first over a massive macro quantum space-time superposition.
See, you get it.
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