12 ms·
Is Faster-Than-Light Travel or Communication Possible? (1997)
- Zenst 10y agoNice list and currently no. But many theory's that say it is possible, no experiments shown it to happen and indeed faster than light gets for many down to causality. Not saying it is impossible, but in theory anything is possible until proven or disproven. Another article that raises the same question is http://www.bbc.com/future/story/20150318-will-we-ever-speak-across-galaxies http://www.bbc.com/future/story/20150318-will-we-ever-speak-... Now one aspect I'll add is that it may be possible but would the integrity of the information communicated be maintained and with that it would still be a case of no. For me a related theory is that black holes convert mass into energy and that energy dissociates with current space and time and some of that ends up at physical location in space of 0,0,0 and time 0 as that is the earliest point in time and space. That and with all black holes over time venting so to speak to that point in space in time, was the reason for the big bang. Again a theory of mine. Now in that case something from now has gone back in time and yet has it gone faster than light? Or indeed is there anything sent that is recognisable from when it entered and in that case - no. So again whilst FTL communication may be possible, the whole aspect of integrity of that communication is a whole other aspect. Equally the speed of light, there is another theory that the speed of light has varied over time (VLS Variable light speed) and whilst some observations lend themselves to this, it is still a theory. So that is another aspect in this that needs to be factored in. In short light may of been faster in the past, or it may of been slower and that add's a whole new layer of complexity upon this issue. Science is fun isn't it, be darn boring when we as a species learn it all, but not in any of our lifetimes and that for me is a good thing. Though like many theories and great scientists there are and still are people who just dismiss without debate and with that how many people in the past burned or killed for saying the earth is not flat. Still be interesting for constructive perspectives and debate upon this, but alas as a subject many just dismiss and blindly label. Which is sad, in any time, even today :(.
- clock_tower 10y agoWhen exactly were people burned alive, or killed in general, for saying the earth isn't flat? The first article of the _Summa Theologica_ discusses how to prove that the world is round; no Christian took Genesis' cosmography particularly seriously until biblical literalism and the Reformation. You might be thinking of the heliocentricism mess; but Bruno was burned for beliefs that had nothing to do with heliocentricism, and Galileo was only confined to house arrest -- and that after the Pope had tried to compromise with him, and Galileo responded by putting the Pope's arguments into the mouth of a simpleton in a revised version of the _Dialogue Concerning Two World-Systems_. This is a tangent to your main argument, but it's an important thing to get right; you can't reach truth if you start from misconceptions...
- Zenst 10y agohttp://www.biographybase.com/biography/Bruno_Giordano.html http://www.biographybase.com/biography/Bruno_Giordano.html Yip your right, my mistake, good to learn. Least none can name and was indeed thinking of Bruno at the time, my bad. Thank you for the correction and sorry for the misconception correction by me.
- clock_tower 10y agoThanks for not turning it into a fight! (And I apologize for my contentious tone; I was inappropriately gearing up for battle there.) I thought you might be thinking of Bruno, the scientist who really was burned at the stake; it's a good thing for everyone that this wasn't for his science. (Of course, it would've been better if people weren't burned at the stake in general. Certain modern elements have reminded us of how painful a death that was...) I also learned a few things about Galileo from Biography Base's article on him; thanks for that link! The more I learn about that case, the less it sounds like Religion versus Science and the more it sounds like a conventional miscarriage of justice. A frail, sick, stubborn old man should never have been treated like that, even though he did call the Pope a simpleton. The Pope is the Pope, and has certain standards to maintain; it doesn't reflect well on Christ when His Vicar abuses the courts to make trouble for people who insult him.
- chopin 10y agoThere should be (1998) in the title. Not that it changes much...
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- SFJulie 10y agoHe forgot the permutation operator in quantum mechanic... Where causality is put at the intrication level, and measurement of two intricated quantic system are coupled by one another if and only if you can make in the same hesienberg window of dE.dt ~ hbar/2. Hence potentially being an ansible (like in orson scott gard books. (quantum teleportation, alain aspect 1997) The only problem is having synchronization of time over distance and hoping the dE.dt does not require exponential energy growth over intended distance of communication and that the energy per bit is not too expensive. But yes this article was indeed done in 1998 where USA university may have discarded science from under developed countries such as France.
- sevenless 10y agoThe thing is that subjectively "FTL" travel, a la Star Trek, is totally possible thanks to special relativity contracting distances between objects. A little math shows the relative velocity in which you travel one light year measured in a rest frame, in one year in your spaceship's frame, is 70.7% of the speed of light. If you happened to be moving at the ludicrous speed of the "Oh-My-God" cosmic ray recorded in 1991, it would take you three seconds of your time to travel to the center of the galaxy. That should be good enough for anyone! https://www.fourmilab.ch/documents/OhMyGodParticle/ https://www.fourmilab.ch/documents/OhMyGodParticle/
- simonh 10y agoBut length contraction means that, subjectively, you'll think you've only travelled a few hundred thousand kilometers.
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- sevenless 10y agoThis explains the famous line from Star Wars about the Millennium Falcon "making the Kessel run in less than 12 parsecs". George Lucas was obviously hip to the implications of special relativity.
- dec0dedab0de 10y agoI think the retconed explanation is that the kessel run involves going around a black hole. Bragging about parsecs is because the slower ships had to completely steer free of the blackhole, while faster ones could get closer and break free of it's gravity, thus shortening the overall distance traveled.
- mikeash 10y agoI prefer the explanation that Han Solo thought they were total rubes, and gave them some nonsense just to impress them. Indeed, the fourth draft of the script has this comment after the "twelve parsecs" line: "Ben reacts to Solo's stupid attempt to impress them with obvious misinformation." The final draft says he's "obviously lying." I feel like this ridiculous retcon involving black holes, rather than sticking to the simple human explanation of braggadocio, is a microcosm of everything that subsequently went wrong with the prequels.
- cmrx64 10y agoSee also https://arxiv.org/pdf/1211.6468.pdf https://arxiv.org/pdf/1211.6468.pdf, which accompanies a theory recently published in the Archive of Formal Proofs: http://www.isa-afp.org/entries/No_FTL_observers.shtml http://www.isa-afp.org/entries/No_FTL_observers.shtml It states rigorously what it means to be an object ("observer"), and what it means to travel faster than light, and proves that observers cannot travel FTL. In special relativity, though, not GR yet.
- simonh 10y agoI'm with Betteridge on this one.
- aaron695 10y agoThinking you can go faster than light for communication is the same as believing perpetual motion or even being a flat earther. You can't do it, there are no hacks to do it. It's a law of the universe. No matter how many SciFi movies tell you other wise. I just don't get the acceptance of this anti-scientific concept.
- jandrese 10y agoThis is exactly right given our current understanding of the universe. FTL travel violates causality, which is a fundamental principle of the universe. I wouldn't go quite so far as to say it's totally impossible though. There is a whole lot about the universe we don't understand and I can't rule out the possibility that there are entire branches of mathematics and physics that we don't know about.
- mariodiana 10y agoCan you or someone else "explain to me like I'm five" why faster-than-light travel violates causality?
- SerLava 10y agoTo travel faster than light, you'd have to skip places in space instead of moving through them continuously. So you'd be constantly appearing out of nowhere. Other reasons.
- euyyn 10y agoIt's one of a bunch of mathematical conclusions of Special Relativity (the most famous one being that objects at rest have a "kinetic" energy of mc^2). I'll try to explain it simply, without the math: Imagine a friend and you, moving very fast with respect to each other. You measure your friend's clock as advancing slowly (due to time dilation), on account of the fact that he's moving with respect to you. But your friend measures _your_ clock as advancing more slowly than _his_, because motion is relative. The way to reconcile this mathematically is to give up on absolute simultaneity of distant events. In other words, when two things happen in different places, at the same time according to your clock, they happened at different times according to your friend's clock. This is analogous to how you measure your friend to be in different places in different times (because he's moving with respect to you), but he measures himself to be stationary, always in the same place. To recap: If comparing things at different moments, "being in the same position or not" is relative to the observer. If comparing things at different places, "happening at the same time or not" is relative to the observer. That's how causality comes in. If your friend tosses a very fast ball at you, and the moment you receive the ball you start towards him faster-than-c, you'll arrive where he is before he tossed it (if you went fast enough). That's what the equations say. Now the breaking of absolute simultaneity allows naturally for disagreements on what of two things happened first, assuming they happened far enough from each other that light couldn't cover the distance in time. But by putting faster-than-c velocities in the equations, we have your friend and you disagreeing on what happened first (him tossing the ball, or you arriving where he is?) in what (to him) is the same place. And it's not just a confusion of the mind: all your measuring and recording artifacts will agree with you, and all of his will agree with him. The mathematical conclusion is that if you can send information faster-than-c, you can send it back in time and break causality.
- brainpool 10y agoIf it is imaginable I believe it is possible. Within our current understanding of physics not doable, but that's just theory.
- Abraln 10y agoI agree with the link that it really depends on what you mean by FTL. At first glance refrigerators seem impossible because they would reverse entropy. The key is that it does not practically matter if they do or not, they just need to achieve the desired result. I would personally consider FTL anything that would beat light traveling through unaltered space-time.
- dang 10y agoTwo previous discussions: https://hn.algolia.com/?query=Is%20Faster-Than-Light%20Travel%20or%20Communication%20Possible%3F&sort=byDate&dateRange=all&type=story&storyText=false&prefix&page=0 https://hn.algolia.com/?query=Is%20Faster-Than-Light%20Trave....
- stupang 10y agoYou know, the Speed of Dark makes the Speed of Light look slow.
- amag 10y agoAnd Ludicrous Speed makes Speed of Dark look slow.