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.
So you're saying that, if you're traveling in space it seems like you could travel in time at the same space.
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.
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.
What is time, if not curvy space?
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. :-)
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.
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:
Perpetual instability, where the timeline changes each time the time machine is used but never reaches the same state twice
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
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
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
Primer is one of my favourite movies ever. It was made on a budget of 3 peanuts and pocket lint, and it shows, but damn it's an interesting premise.
Great movie. I enjoyed the lofi feel of Primer as it handled a really fun concept.
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).
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..
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
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.
Someone should build a space machine so we can travel through space freely
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.
I honestly think this would not happen because you would be time-travelling in the Earth's frame of reference
Yeah, or if the time machine is genuinely a teleporter, then the invetor should at least know how to correct for drift.
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.
How, uh, far back in time did you want to go?
That's probably the guy that offered people a few dollars and a chair to watch all of earth's history.
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
Why would you time travel to a position relative to anything other than the earth?
A place for majestic STEMLORD peacocking, as well as memes about the realities of working in a lab.
Rules
This is a science community. We use the Dawkins definition of meme.
