I know practically zip about science so I’m absolutely positive there’s a huge hole in my thinking on this. I understand that it is impossible for people to accelerate to light speed as it would take infinite energy to achieve that. OK, that’s point one.
Point two. We know that it’s possible for something to travel at that speed and that is light itself, photons. The next step in my thinking may be shaky but here is point three. Photons can surely bear information. Even the absence of a photon or its presence can convey a message just as on/off in a computer does. If I send a stream of photons towards Alpha Centauri and send them in a pattern surely I have sent information at the speed of light. Someone at the other end could decode that pattern just as a computer does and reconstruct the message. That message, just as with a computer, could be anything. A two word greeting, a picture, a film, the current day’s news. And perhaps at some point in the future instructions for assembling an exact replica of the human being who sent it, together with all the thoughts, memories of that human being. In other words I send such a message and in however long it takes light to get to Alpha Centauri and for my message to be reconstructed I am to all intents and purposes there in that far away system and I have traveled there at the speed of light.
As I said I know there’s a flaw in my thinking but on the basis of this surely we can send information at light speed. But doesn’t that mess with causality?
Yes - we can send information at the speed of light, but not any faster.
And if it were possible to build a practically-functioning teleporter which worked by transmitting the information about a teleported object (which is more or less what you’re describing), then it would be possible to teleport objects at the speed of light, but not any faster.
I guess the flaw, if there is one, in your thinking is that transmitting information about an object is not the same as accelerating that physical object. Causality is only violated if you can exceed the speed of light, which you can’t.
You’ve stumbled on a very commonly used technology in science fiction. (The TV Tropes page is especially rudimentary and barely scratches the surface.)
You don’t need such a complicated setup to show that information can be transmitted at light speed. And it bears repeating that transmitting information at light speed doesn’t mess with causality.
As others have pointed out, our eyes receive information at the speed of light all the time. If you’re looking for a technology that does this, it’s called radio.
Consider this thought experiment. Suppose, through nanotechnology, we can seamlessly replace one out of your hundred billion organic neurons with a processor that exactly replicates the input/output of that neuron. Your brain would continue functioning exactly as before, presumably you would no more argue that you are no longer “you” than if you cut your toenails. Now we replace a second neuron. Now a third, a fourth, always maintaining the same seamless functionality. Eventually all of your organic neurons are replaced by synthetic neurons. None of the original organic material remains, yet your brain continues to function just as before. Is that still you? If not, when did it stop being you?
This is obviously how to do this, given the known limitations about the universe. A couple of notes :
a. Faster than light travel is a literary plot device used by science fiction. Fiction, which is coming from centuries long storytelling traditions, is most interesting to human if it has human characters. You might notice that in classic stories of Greek gods, the gods, while supposedly inhuman beings blessed with incredible powers, act basically like humans…
Well, humans are well known to live only a few decades and then fail and then die. So in order to have a story where humans deal with interstellar distances, they need a short cut past well known laws of physics, or they will be elderly by the time they do a few interstellar trips, even at near lightspeed using some impossible to construct starship.
b. Realistically, it will be possible before 2100 to develop some type of artificial sentience or copy human minds to a computer. The technology is the ultimate end state, the ultimate goal, of the last several centuries of progress. Either way, this will happen long before starships of any sort are possible. Being living inside computers would have
Variable clock rates
No artificial lifespan limit
That’s realistic. All the credible known information says this is basically a done deal at this point. It’s just a matter of development time. The fact that artificial neural networks can now emulate any simple single function of a human, and can now stomp humans at a growing number of cognitive tasks, and that an accelerating rush of billions of dollars are flooding into developing better machine intelligence are all clear signs I am right.
Anyways, with beings with no lifespan limit and variable perception of time, interstellar travel is entirely practical.
nitpicking the nitpick … in the West, using a torch will get us arrested for attempted arson … unless, oh no, did we already set the forests on fire? …
You replacment neurons are replicating the input and output that the original ones used to receive, but does it change that input/output over time, as a human’s neuron would as you gain memories and experiences that change the membrane potentials?
It seems that if you did that, you’d still be you, but you’d always be you, and could never change. Are you the same you from ten years ago? I think not. But if your brain was all processors, you would be.
Actually if you can get your spaceship close to the speed of light you can easily survive a trip to anywhere in the universe due to time dilation. Thousands/millions (or more) years will have passed on earth but you’d still be young.
You have to get very close to the speed of light for this effect to amount to much though but it is possible in theory even if near impossible in practice.
This is a spin on the Ship of Theseus thought experiment posed by Plutarch (so it’s been around a long time).
But the thing is our body renews itself all the time. Old cells die and new ones take their place. I am not sure there is a piece of you that is the same as it was seven years ago (not sure about brain cells or nerves).