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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.
The goal posts and yard lines were all just decorative. People would come from miles away to sit and watch the field for 2 or 3 hours. Girls would do flips and shake pom-poms to encourage the grass to grow. Luckily the time traveler brought their egg ball with them and figured out something to do in these fields.
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.
I teleport two Klingons every morning and I’m still late to the staff meeting.
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.
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.
Sure, but it’s a lot of fun to think about :D
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 :)
You might have better luck and accuracy using our galaxy’ s black hole for reference marker depending on how much time you intend to traverse
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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
In most media time machines are also teleporters - many are explicitly so, with the destination space needing to be chosen at the same time as the destination time, but even when that’s not shown they still make the time traveller suddenly vanish and then just suddenly reappear elsewhen.
One movie I’ve seen with a more “realistic” time machine is Primer. It’s not at all a teleporter or portal. Very slight spoiler:
It sidesteps the whole issue that OP presents because the place where you exit the machine after traveling is just where the machine is when it’s turned on to begin with. You can’t time travel outside the machine, including to before it exists, and your path (in all four dimensions) is contiguous.
I prefer the H.G. Wells The Time Machine style of time travel , where you affect the flow of time instead of a discontinuous jump.
You’re still attached to your current location, things just happen faster (in forwards or reverse). It also means that time travel takes time, which can be a handy plot tool.
Edit: grammatical swipe keyboard errors
Great movie. I enjoyed the lofi feel of Primer as it handled a really fun concept.
Same with The End of Eternity - they can travel to different times at which the machine existed.
In fact, isn’t it a bit similar with the only ‘real’ possibility of time travel - you create a wormhole and take one end on a relativistic journey to create a time difference between the ends, but the only possible travel is between the two ends that you have created.
Guess this is why the TARDIS had to be a space ship as well.
Time machines have been invented dozens of times since the 1800s; there’s s trail of them drifting through deep space.
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…
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.
How, uh, far back in time did you want to go?
https://astronomy.stackexchange.com/questions/33514/how-fast-are-we-moving-relative-to-the-cmb#33515
Earth moves with somewhere between 230-500km/s, long term average should be 370 km/s
https://en.m.wikipedia.org/wiki/Formation_and_evolution_of_the_Solar_System
https://en.m.wikipedia.org/wiki/History_of_Earth
The solar system and earth formed 4.6 billion years ago.
https://numbat.dev/?q=370+km%2Fs+*+4.6+billion+years+->+ly⏎
That means the solar system travelled 3.45-7.67 million light-years (5.67 for the average speed) since then.
That plural form (millions of light years) is borderline, but actually not incorrect.
Time machines don’t exist and (as far as we know) cannot exist. Therefore, we can say they work however we want. If you can travel back in time, surely you can do that while remaining close to an arbitrary point of reference.
Hence how the artist was able to choose that the time machine in this context rewinds time while conserving the universal position(?)… Relative to the center of the universe(??)… assuming eucledian space(???)
I honestly think this would not happen because you would be time-travelling in the Earth’s frame of reference
Someone should build a space machine so we can travel through space freely
We are all space machines on this blessed day
Blessed be
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?
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.
So either we would have to invent teleportation along with time travel/ have some sort of "magnet pad’ that must exist and not break at all times on earth, or its the time machine type where it just fast forwards everything around you until somehow you’re in a mall
Since space and time are intertwined, we must travel both to achieve the desired goal
Maybe this is why Stephen Hawkings time travellor party never worked out lol
I should hope that if we had time travel landing pads, we’d have a pretty good log of maintenance times in the future.
The tough part to figure out, though, is that the more a pad is used, the more maintenance it requires, which in turn modifies the logs.
Well, since no one bothered to create a savepoint, we can’t travel back in time anyway.
