You just sent electric data forward in time.
this post was submitted on 06 Dec 2023
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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
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.
"300 m/s ought to be enough for anybody"
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?
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
Ok there Hououin Kyouma
It means no worries
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.
It needs a so-called wormhole, or in popular science also known as Einstein-Rosen bridge.
I dont think it moves at the speed of light unless its using optical connections.
Optic fibers normally have light moving inside them at something between 1/3 and 1/2 of the speed of light.
And electric signals in network cables usually move at something between 1/5 and 1/3 of it.
So neither i guess. It nakes sense as even fiber optic uses a medium to transmit the light.
As I understand it, massless particles always have to move at the speed of light in the medium through which they’re moving. The catch is that it varies depending on the medium. The speed of light is only equal to c in a vacuum. Even in optical fibers, light speed is < c.
If I remember correctly the only massless particles that travel through space are photons. Photons are what make up light so to say they travel at that speed is a little redundant.
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.
Time is relative. So, the electrons might experience a different "time" because they are moving closer to the speed of light, but they cannot traverse further in time. The twin paradox is interesting because humans change as time goes on. The internal changes a human experiences as they experience time dilation is what we really are measuring. If the twins were both frozen in time, we wouldn't really care that they experienced different time references during their trip.
The electrons are basically "frozen in time" in this regard. The information they carry isn't changing in their relative frame. So the end result isn't super interesting. If the electron changed over time - and we moved it close to the speed of light - that change would be relative. The information we sent would be different than when it arrived.
In other words, they do experience different time frames than something 0.00000001c, but since they don't change at all it's not really meaningful that they are - perhaps - less "aged" by the time they reach their destination than we are.
Maybe. Anybody who says no is forgetting that we still know very little about the universe. It’s possible that we’ll find a way to transmit data to other time periods.