Given the fact that data is an electric circuit of ones and zeros, flowing at the speed of light, could we technically send information across time?
You just sent electric data forward in time.
In a sense, we all are Time Travelers! We are surviving each and every Active Time-Point in this timeline…
Not the quote I was looking for, but it will do
I thought of XKCD 209.
No. The universal speed limit, the speed of light, is also the limit at which information or data can be transmitted.
What a coincidence! /s
That’s actually not as obvious as it might sound. The thing is, as far as we know, light seems to have no mass¹. No mass means no inertia. So, if it accelerates at all, it should immediately be at infinite speed. But for some reason, it actually doesn’t go faster than what we typically call the speed of light. And we assume, that’s the case, because that’s actually the speed of causality.
So, it’s reversed. It’s not that light is just the fastest thing and as a consequence of that, nothing can be transmitted faster. No, it’s actually that there appears to be a genuine universal speed limit and light would be going faster, if it could.
¹) Light is still affected by gravity, e.g. can’t escape from black holes. We do assume that gravity is just a ‘bend in spacetime’ because of that, meaning even any massless thing are affected by it, but yeah, we’re still struggling to understand what mass actually is then.
Don’t worry, they’ll fix that on the next patch. The programmers were lazy so put an arbitrary speed limit thinking nobody would find out.
Photons are massless and along with other massless particles are known as Luxons because they always travel at the speed of light. But notice that the speed of light varies depending on the medium that light is crossing. (Eg 300,000 m/s in a vacuum . 200,000 m/s in glass)
So you could certainly transmit data faster than light through glass by simply transmitting it in a vacuum. But there’s little practical use except perhaps gravity wave detectors.
There are a class of particles that always travel slower than light (unless you accelerate them with infinite energy) and also a theoretical and controversial class of particles that travel at infinite speed and would require infinite energy to slow them to light speed. (If they did exist no means has ever been postulated to detect them)
There is an experiment that has been trying to receive a message before sending that message for a while now, unsuccessfully.
You could very easily send data forward in time though. If you think about it, I’m doing that right now. As you did when making this post. You posted it 11 hours ago and I only just now saw it, in the future.
yeah, but you can’t reply to me back 11 hours ago, when I posted it, right? that was my initial question, whether it’s possible to achieve that in theory or not.
That is correct. And it’s neither possible in practice, nor in theory.
Well, I’m going to give the party-pooper response, even though science fiction and pop-science love to fantasize differently:
The past and the future are theoretical concepts. They don’t actually exist in the sense that you can ‘send’ something to them.
Obviously, you can write data to a hard drive and then read it out after a week has passed, but presumably that is not what you had in mind.But that’s also the essence of the time travel that the theory of general relativity allows. You can travel forwards more slowly along the time axis by travelling more quickly on the space axis (close to the speed of light), which means you might just need to spend 5 perceived years to end up in the year 2200.
Similarly, you could take a hard drive onto this journey and it wouldn’t have fallen apart in that time.Travelling back in time makes no sense in general relativity. You would need to reverse causality for that, which is on an entirely different level from merely slowing causality down.
General relativity would mathematically allow for the existence of wormholes, but that’s pushing the theory to extremes where it might simply not be applicable to reality anymore. We certainly have no actual evidence for wormholes.
Even wormholes break causality. Doesn’t matter the method, folding space, black holes, if you can arrive at a destination faster that light thru normal space can get there, you can know of things before they occurred.
Hmm, but why do you think these things haven’t occurred yet?
As far as I can tell, the speed of causality means things can have occurred in a certain location in the universe, but it takes time until the effects have permeated into the rest of the universe.
So, it’s like a shockwave from an explosion. The explosion happens, but it takes a few seconds until you feel the shockwave.
Well, with the difference that you can see an explosion before the shockwave. When we’re at the speed of causality, literally no evidence will have arrived in your position until it does.So, one could go meta-philosophical with basically “If a tree falls in a forest and no one has heard it yet, did it actually already happen?”, but yeah, I don’t think that’s terribly useful here.
And well, if we treat it like a shockwave, let’s say you detonate some TNT and step through a wormhole to somewhere 20 km away. You would know that the shockwave will arrive soon, but does that matter? The shockwave will still just continue pushing on.
And I guess, crucially, it did already happen, so you can’t do the usual time travel paradox of preventing that it would happen.
If I understand you correct, it is not important that you know if it before it happened, because literally no evidence will have arrived until it does. Except that is not correct. Your knowledge is literally and entirely evidence so something did arrive. Effectively you are in a timeline that is behind the event’s timeline.
But more to the point, you could take this knowledge, fold the universe again, and being that you are in a timeline prior to the event, you could arrive at the source event before it happened. And stop it. The paradox then. How did you know to do something that never happened?
And you wouldn’t have to reverse causality to travel backwards in time. You would just have to travel faster than the speed of light.
If you can travel faster than the speed of light then you can arrive at a destination before you left.
Alternatively, you would need to generate some sort of negative energy and then enter into a wormhole with the negative energy. As you cross the perihelion of the wormhole there is a possibility that rather than being crushed and destroyed and by the unimaginable cosmic forces you are experiencing that the negative energy would cancel it out and you would be able to travel through the wormhole to any point between the moment that you entered it and the moment that it was created.
Both of these statements come with the caveat that these are based on theories and so my ability to explain them is limited not only by my understanding of the theory but also my ability to explain the information that I have, and there is the possibility that even though these are somewhat plausible scenarios once you overcome the massive gap between where we are and where we would have to be to implement them, there is a chance that a new better mathematical theory will replace this information and prove it to be completely and totally false.
And you wouldn’t have to reverse causality to travel backwards in time. You would just have to travel faster than the speed of light.
Another term for the speed of light is the speed of causality as it is the rate with which causality propagates through the universe.
Traveling faster than the speed of light is, by definition, reversing causality.
I think you’re looking at it from the wrong frame of reference.
Technically, time is still moving forward. Time has not moved backwards on a universal scale, you have just traveled in such a way that you arrived at a point in time where your temporal reference frame is different than the rest of the time you are currently occupying.
Your causality has remained uninterrupted by traveling faster than the speed of light.
Traveling faster than the speed of light means that you have exited the universe and re-entered it at a different point.
At the point that your causality reintegrates with the current temporal causality that you find yourself in then a new causality is created.
Once again, this does not alter causality.
You’ve just put a stitch in time.
And you wouldn’t have to reverse causality to travel backwards in time. You would just have to travel faster than the speed of light.
If you can travel faster than the speed of light then you can arrive at a destination before you left.
I know practically nothing about all the wormhole theories, because I just don’t consider them relevant, but from a logical standpoint, the above does not feel correct to me.
The thing is, you would arrive at your destination before the light would arrive there from where you started. So, you could take out your telescope and potentially watch your own launch.
But that doesn’t actually put you into the past. It just looks like it when looking into the direction you came from. Light from the other direction will look like you’ve fast-forwarded through time, because you now get more recent imagery.
I don’t have another explanation why someone might think, this might put you into the past…
Please send me the numbers of the lottery numbers last week. As you already know, I will split 50/50.
Sure, last week they were 53 8 25 49 20 33.
Fuck.
Batteries send electricity forward in time.
Hard drives send information forward in time.
I’m not sure what you’re getting at.
This is me sending a message forward in time
Can confirm, I received this message approximately 180 minutes after you sent it. Strong Work!
time isn’t a terrain across which we can travel or send messages… thinking of it that way is sort of the same mistake as imagining X-wing fighters zooming through asteroid fields and engaging in dogfights… in the latter case, we are imagining what it would be like if the physics of aerial flight applied to the realm above it - space…
with time travel or hyper-temporal communication or something, we are imagining that what we call time is a static terrain that has something like “addresses” where events reside permanently… we are trying to apply the rules of the 3 dimensional realm (travel to and from addresses) to the one above it, and they don’t fit…
there is only one temporal “address” associated with this reality, and we already occupy it… time is essentially too busy continuously creating this reality to remember or know about others…
It needs a so-called wormhole, or in popular science also known as Einstein-Rosen bridge.
Ok there Hououin Kyouma
It means no worries
Sounds like a problem-free philosophy.
Well, data just doesn’t really flow at the speed of light. It’s a really really complicated thing to discuss in terms of physical circuits because the true picture involves considering how the EM field evolves. Electrons in a circuit move at extremely slow speeds, ~millimeters per second.
The good news is you don’t need to send information particularly fast to send it through time. Generally in physics, we build time travel systems by creating extremely curved spacetime that contains paths to the past, theoretically you could send light through such a path to transmit information back in time. As someone already mentioned, you generally need negative mass to construct these.
If you have negative mass there are three options I’m aware of:
- Wormholes, stabilised and moved in the right way can form a link to the past (but only as far back as the moment they were created, this is true of all time machines as far as I know)
- Rotating torii of spacetime. Spinning spacetime is well known for creating weird time travel effects, a related option is an infinitely long rotating cylinder.
- A rotating warp drive. This thing will explode in a high energy shower of particles and thus it’ll be nearly impossible to use, but a friend of mine recently found a way to get particles to travel back in time through it.
If you want to send information into the distant future, you could get really fancy and scatter some light off of a black hole or something.
Really fun Scifi book The Light of Other Days I read about this about a creepy rich family that accidentally invented wormholes to see back in time but couldn’t send anything. It gets out and now everyone can view anywhere anywhen,
That sounds dope. I’m putting that on my Kindle right now
Edit: actually I’m having trouble finding it, The book that’s coming up doesn’t sound like it. And the other one that is coming up is a romance about hockey. Do you happen to know the author?
Edit #2: I think I found it, " the light of other days" by Arthur c. Clarke sounds like it might be the book you were talking about.
woops, my apologies it was this novel. https://en.wikipedia.org/wiki/The_Light_of_Other_Days, editing my previous :|
Idk, but it really sounds like something that could be possible in a future. Sending matter sounds difficult since the mass problem but electric information has barely any mass (or it does not?) Something really difficult would be calculating the possition of earth in the universe in the past and sending a signal to a receptor in the past earth
Electrons have mass. It’s tiny but a very important distinction between them and massless particles like photons.
Forward, yes, easily.
Backwards, maybe, but not easily.
Before we can ever find out if we could send information backwards in time, we will need to discover and utilize negative energy, which is a theorized form of energy that has not been proven to exist although mathematical models hint at the possibility of its existence.
At the same time though, those mathematical models are abstractions that attempt to correlate real-world information with theoretical frameworks and because of that there are margins of error that we cannot currently determine in those mathematical models.
Further, new information that comes out as we continue to explore the universe may invalidate those mathematical models and replace them with a more accurate mathematical model.
That information may completely eliminate the possibility of the existence of negative energy.
Finally, even if negative energy is proven to exist or something close enough to it that it fills the Gap in the mathematical models correctly, there is no guarantee that we can harness that energy and use it to send information backwards in time.
However, I am saying that there is a chance, but it is exceedingly doubtful and probably a very very long time away.
