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Use a space time machine. Problem solved.
You need to add dimensions and relativity.
Don’t look at me. I’m too lazy.
Don’t worry, it has already been done. https://en.wikipedia.org/wiki/TARDIS
Since relativity tells us there is no universal reference frame, then it having its reference tied to earth is perfectly valid.
Also sidenote: my favourite idea about time travel is that time travel is entirely possible, but will never be invented, because the timeline where its not invented is the only stable timeline. Because any timeline where it IS invented gets changed as soon as you use it, meaning the timeline changes over and over again every time time travel is invented repeatedly either infinitely or until someone accidentally creates a timeline where its never invented, only then does the timeline stop changing and we can actually experience it. So because we exist and can experience time, we can deduce that we will never invent time travel.
There can be stable timelines with time travel - there’s actually 3 states:
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Perpetual instability, where the timeline changes each time the time machine is used but never reaches the same state twice
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Perpetual cyclic stability, where people’s actions in modifying the timeline lead to it eventually reaching the same state, eg. you go back in time to kill someone who becomes evil and oppresses you but the near death experience leads them capture you, so you can’t time travel any more, and to blame your people and start oppressing them, leading to the same actions
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Stability without time travel, which is the default state but incredibly hard to get once time travel is invented as with nobody to stop time travel being invented it would probably get invented again, however parts of a cyclically stable timeline could have nobody having access to time travel, but any actions by time travellers to stop time travel would likely lead to the second rather than third option
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Yeah I think we don’t have to worry about it for the same reason why you don’t have to worry about getting thrown backwards when jumping in a moving train.
Rotational reference frames are out though! (Unless you want to deal with magic forces acting on your masses)
And since the earth rotates around itself and the sun, and the sun rotates around the center of the galaxy, you will always have to deal with a moving target.
Since I stay on earth now when I’m moving forward in time why wouldn’t I stay on earth when I move backward through time?
Sure you can, but you need to adjust your position due to centrifugal forces all the time. A time machine would have to do that as well.
If a ball is flying in a straight line through space with a speed of 1m/s I can predict without much math where it will be at any point in time. In fact, if the reference frame is chosen such that the ball is stationary you don’t need any math at all, because the ball doesn’t move!
However, if you have a set of two balls orbiting each other you will always have to do math to calculate their position. I mean technically you could choose the reference frame that is rotating in sync with the balls. But still you need to do math to check that the centrifugal force, which is a real force coming from nowhere in this reference frame, exactly cancels out the gravitational pull between the two balls. Because rotating reference frames are not equivalent to each other!
I really don’t get why the time machine would have to do any calculations at all. The time machine is in this reference frame. You seem to assume that by going back through time you’d be teleporting through time, which leaves the open question of where you’d appear. However, I’d much rather assume that you’d actually be “going” through time. You wouldn’t cease to exist until you reappeared somewhere. Instead you’d be in the machine for some time until you’d get out of the machine again. That’d mean neither you nor the machine ever leave the reference frame.
Fair enough :)
How much do you know about the “double slit” experiment and its subsequent variations? Because I think that’s a rabbithole you’ll enjoy. That first video is really just context; this next link is another video in that series, and this is the one that really pertains to the consequences of time travel: https://piped.video/watch?v=8ORLN_KwAgs
Time and space are the same thing, if you’re traveling in time it seems like you could travel in space at the same time.
Yeah but traveling in space takes time, so you can reason that traveling in time takes space.
Right so have we tried putting the Time Machine in the middle of a football field or smthn?
Yes and that’s how we ended up with American Football. In the original timeline, it never existed.
how do i get to that timeline
You have to turn left in 1867.
I thought it was Albuquerque
That’s where you must have taken a wrong toin.
Which is why the deLorean was an amazing time machine, obviously.
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.
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.
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.
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.
If they were really the same thing, traveling into the past would be trivial. Greg Egan’s Orthogonal series explores the consequences of space and time actually being the same thing. You can also the the difference in formulas related to proper time, where terms for space and time have opposite signs. Space and time have the same relationship to each other as real and imaginary numbers, in a fairly literal sense.
Ahummm, well actually, * adjusts monocle * time travel is not possible and since nobody has invented time machines yet, neither of these scenarios would happen in reality.
This meme format having a redemption arc is my favorite. It wasn’t super sexist, but it was just unnecessarily sexist.
Rescue peepo from the nazis next.
This is why you have to calibrate your time machine to track the relative gravity well.
I think gravity is the solution to this problem. The time machine just has to be able to lock on to the earths gravitational force from across time
Can you detect rotational velocity using gravity?
Earth rotates at about 460m/s around it’s own axis.
and I’m sure scientists have access to a more precise number than that.
we dont have to detect what we can calculate
We have a machine that can track planets through time and space and you only want it to work on Earth?!?
Why would it only work on earth? How do you think we took close up pictures of pluto?
It would only work on earth because we’ve only given the time/space machine information about the rotation of the earth.
But my question is more about science theory than fiction. Does observing gravity give any information about how fast that mass is rotating?
“It would only work on earth because we’ve only given the time/space machine information about the rotation of the earth.”
So you’re the one that only wants it to work on earth then.
And no. “Observing” Gravity does not give any information of how fast an object is spinning around it’s own axis.
So you’re the one that only wants it to work on earth then.
No. Are you suggesting we supply this machine with the rotational velocity of all planets in the known universe? Or some other solution?
How could we jump to a planet on the other side of the galaxy?
I have yet to stumble across a sci-fi short story about space travelers finding an entire civilization’s worth of dead bodies floating round in space only to realize that they were all time travelers who only got part of the time traveling math correct. They figured out how to get through time but couldn’t figure out how to get through space, but since all their volunteers died, they never figured it out and just kept sending people to their doom.
I feel like this could be a scene in Rick and Morty, with someone commenting, “Guess their Math was off”
There is a sci-fi short story whose name escapes me of a spaceship using some new FTL drive, but has largely been untested due to an impending doom. The math is said to be solid, however.
Anyway the drive powers up, and the spaceship jumps, and… all the crew and passengers are left behind, choking in space.
Sounds like one of the asides from “The Hitch Hikers Guide to the Galaxy”.
I honestly think this would not happen because you would be time-travelling in the Earth’s frame of reference
There is no space reference in time traveling only a time reference, the time traveler don’t change his start point, but the Earth and the whole solarsystem do. If you travel 6 month to the future, you are still in the point where you started, but the Earth will be on the other site of the Sun. A time machine must be a spaceship, otherwise you won’t survive. That is the error of almost all movies about time travel since H.G.Wells.
If you travel 6 month to the future, you are still in the point where you started, but the Earth will be on the other site of the Sun.
Why would you remain spatially locked to the sun? The solar system is moving around the milky way. The Milky way is traveling at around 370 miles per second if we use the universe as a frame of reference. A point is both a place and a moment. Everything is moving relative to everything else. Time travel is also space travel.
This is a huge assumption. Why is it necessary that time would not have a space reference? I’d actually say that based on relativistic physics there probably is a space reference because the dimensions are linked. I think it’s possible that the momentum of the current movement could remain constant and thus stick the time traveling device to the earth. Coming to a complete referential stop in space would require beyond immense energy and be inefficient if one only wants to travel in time
Yeah, or if the time machine is genuinely a teleporter, then the invetor should at least know how to correct for drift.
I mean, it’s the space-time continuum, it’s connected! As the documentary Stargate SG-1 shows, we’re well acquainted with spatial and chronological drift over interstellar distances.
A time machine would necessarily need to have some way of defining what reference frame one is stationary in space relative towards, because there is no universal frame that everything moves relative to. This suggests that a time machine ought to let you move through space as well as time
So to travel into the future and be in the “same place” relative to your planet you’d need to solve the n-body problem for at least your local system to a suitable length of time. A slight error might mean you appear inside the planet or in outer space.
Or maybe I don’t understand this stuff. :-)
You’d just send a drone back, to say 100 years ago, first and have it send you exact coordinates into the future.
Time paradox aside you’d probably have this data already, with all alternatives and can correctly time jump right away.
You’d also need to solve time travel.
Eh, let’s cross that bridge when we get to it
Mass bends spacetime so one could assert that a time machine could anchor itself to a sufficiently large mass, just like how things in orbit are still bound to the earth’s mass.
Well, since this was posted in Science Memes, I’ll be so pedantic that science does not support the idea of travelling back in time.
It does support travelling forwards in time, at various speeds, but you’ll constantly be aware of where you are (even if one method involves travelling really fast and therefore may still leave you in empty space).
I’m traveling forward in time right now.
if you believe in the notion that the universe is cyclic then you can mimic time traveling backwards by traveling forwards, past the end of the universe, and stopping at just the right time in the new universe.
e.g., to get to 1700 you’d go (present time) -> (death of the universe) -> (1700 in next universe)
I mean, personally, I actually don’t believe that the Big Bang created everything out of
thin airvacuum, because much like travelling backwards in time, that would break causality.It makes much more sense for everything to just have always existed and the Big Bang is merely a very visible event + expansion afterwards.
I’m open to the notion that expansion and contraction happen in some sort of cycle, because well, many things do.But for it to be cyclical to the point where it repeats precisely the same? Why?
Can’t we just let the universe flobber on its merry way without assigning some higher meaning to everything it does?
I like the idea that time machines are like phones in that you need a receiver to pick up the signal. A consequence is that you can only travel back to the time that the machine was turned on.
Imagine building the first receiver, and immediately have 20 people spawn within the same space
More like 2 million inconsiderate time tourists comming to gawk at the first reciver…
You may enjoy Ted Chiang’s The Merchant and the Alchemist’s Gate, the short story.
The whole book is great if you like thought-provoking sci-fi premises I guess: https://www.goodreads.com/en/book/show/41160292
Wow, I did not expect to find a fellow Ted Chiang enjoyer. The Merchant and the Alchemist’s Gate is one of my favorite.
You’re in the science meme community of Lemmy, lots of niche folks here
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Nah. Location is relative.
I’d like to believe that mass (and then by extension the Earth) “defines” the spacetime around it as much as it distorts spacetime near it. I suspect this may even be the underlying cause for the observation of speed of light being constant in the presence of earth/solar/galactic movement.
It’d be really interesting if time moves at different speeds in different bits of the galaxy, find out that none of the other solar systems have life because closer to the galactic center of someone dropped a teapot when the first life evolved on earth it still wouldn’t have hit the floor.
Of course there’s a lot of reasons this isn’t the case but I dismiss them by saying they’re all just an effect of distortion due to time variance.
Maybe we’ll get s message from voyager saying ‘arrived at a star 224 light years away, it was super quick because there’s no time in the middle so you just skip that bit’
Similar to a solar system’s habitable zone there exists (or is suspected to exist) a galactic habitable zone. I think because of cosmic rays and radiation. So I guess most habitable planets would have more or less the same time dilation.
