I like to imagine that as soon as we discover FTL and break spacetime, the simulation crashes and the higher beings are annoyed they have another bug to fix
@Derek2k First of all, the comment is a joke. Second, even if the matrix was never created, I think people would still have the theory that we live in a simulation. The theory isn't even mainly based on the matrix, since there are records of it hundreds of years ago. Get your facts straight before commenting next time.
@Derek2k It seems difficult for many people to let go of the dream of FTL. The basic fundamental way the universe is constructed runs counter to the stories we have told ourselves. It's as if the characters on the page of a novel wanted to jump out of the medium of the printed book into a world in which we have no correlation.
The fact 1.2k ppl liked this makes me lose faith in humanity. Do y’all truly believe we are living in the matrix or something. I wonder what y’all would think if the matrix movie was never created.
I landed at the same "strict rules" conclusion back in 2007 when designing a sci-fi setting with FTL. I borrowed a bit from Douglas Adams and ended up with a version similar to one you hinted at. That any attempts to perform an action which would result in a paradox would be met with increasingly unlikely events to prevent it from occurring in the first place. Thus, before sending any FTL comms, or engaging in certain kinds of travel, you have to draw the light cones and think through the implications as shown in your video. Thanks for putting this together. It was nice to see someone think through the same things and tie it into a neat package.
I am doing a copy and paste from a quick thought I had. "Just spitballing here, because I am not a physicist nor time traveler, but perhaps it needs to be viewed in other dimensions rather than with a 2d graph. Say for example someone makes a device that in theory can send an FTL message. They turn it on and send a message, but nothing happens so they think it didn't work. However thinking in the infinite universes model the senders universe continued on it's time line, but the message was received in a multitude of parallel universes. They have zero clue as to where the message came from, but they received it none the less. Or perhaps the universes have a way of keeping things tidy, so too speak. So when the FTL message is sent, how do I say this, the entire universe is sent and is no longer where it was in time. Thinking in terms of infinite universes perhaps there are as many, call them anti universes (empty spaces) in the big empty. So the universe itself where the FTL message originated instantly fills the space where the message is received thus avoiding some weird entanglement of timelines. Sure there might be some side effects such as the Mandela effect, but that is price we pay in order to have FTL."
One small thing: if the message is traveling in a different time perspective than the ship, in what time perspective will this ship be able to decode it? (a reference to Orson Scott Card's books about Ender). I think this is not considered in your diagram.
This is hands down one of the best channels ever! Love each and every video more than the last! Bravo and please keep doing what you do, it's voices like yours that truly touch peoples hearts and minds, revealing questions they never knew they were interested in knowing the answer to! If that makes sense, lol!
Does anyone realise that between us in this comment we might have the same ideas the same way of thinking or even the same habits? So how some people tell and even think that there is no life out there, maybe a copy of our planet or better or even in worse sape, and think that those sapes could possibly be our planet if we continue to live as we do or if we changed some things to the way we live right now. We couldn't know if we'd achieve a better or worse future aside the statistics.
According to bob lazar we already have this tech. I’d imagine by now we’d be able to reverse engineer it. Best believe there’s going to a be a huge tech leap relatively soon.
I would posit that it is possible it's just all about frames of reference. You would not be able to affect anything in your personal referential past. You could observe it, but not change it. I think the diagram is off in using the frame of reference for the STL ship as the "speed" of their FTL message would be significantly "faster" than the message from Earth. The correction for this means that their message would NOT arrive prior to that of the sent message. (On the graph their message would appear to them (could they see the graph) to curve upward past the message point. Using star trek terms if you fired off a message at warp 1 its not going to travel at (warp 1 + full impulse) simply because you were going at full impulse. Basically this graph "forgets" that for all of the pink FTL lines, the straight "space" line is not straight. For them it is a curve, so if you factor that in and the flatten it back out it shouldn't violate causality. I am probably wrong somewhere, it's 2 in the morning...
The diagrams do not seem correct as sending a message faster than light could not arrive before the original STL ship left. I think he is mixing up time travel and speed of light which are 2 different things.
I think you're correct. Basically, the means of "propulsion" that an alcubierre drive or "warp" drive would use manipulates space. You are not traveling ftl in terms of momentum, you are bending space so as to take a path shorter than the light is taking. I think technically you aren't moving, space is. For the record, I think that an alcubierre drive is impossible because you need imaginary materials. But since the video is referencing that as the means of propulsion, the argument, as I understand it, that there would be causality issues is incorrect.
It may be right or wrong but the fact that it is showing 4 dimensional space-time on a 2 dimensional graph, it's like trying to show a 3D cube in 1D, it's simply not doable or at least it seems to me. From what I learned we are able to show a cube on a 2d sheet just because we are able to visualize the depth of the image and draw a "line behind the lines" that how we create 3d in short we are able to circumvent one dimension by imagining it so 4d can be shown in 3d, 3D in 2D, 2D in 1D, jumping from 4D to 2D doesn't make much sense and many things may not match like they should. That I think is the main problem here that there is just no way that he could show what he wants on 2D sheet. Rather than FTL I am more convinced by Einstein-Rosen bridges theory beacuse from what I know they go through additional 4th dimension of space there for not creating this paradox if its true. (sorry for mistakes if any english isn't my first language)
@Peter Ingraham no, what I am implying is that this graph is uses a straight line (thus treating it linearly) vis a vis space whereas the whole concept discussed involves bending or folding space. I do not think relativity presents a problem as I have discussed as I believe it sorts itself put if you discount momentum and the standard rules that apply to speed and motion as you would have to when folding space itself. Similarly to how the rules change when you approach a black hole they would change when you folded space. As such, this graph assumes that if they are traveling at (using star trek references just for ease of discussion) warp 1 and fire of a beacon at warp 1 it will be traveling at warp 2. It will not. I posit that folded space travel is a definite limiter such that you cannot increase the speed simply by initiating a launch from something going at speed. As such it would APPEAR to curve away from the perspective of the FTL ships view on the graph IN ACCORDANCE WITH RELATIVITY. Whereas it's not actually making a curve on the graph because the graph treats space as linear and FTL travel does not.
Saying that "the line is not straight" and implying it should be straight is basically equivalent to saying "relativity is incorrect." Now, you can have FTL travel AND causality if you scrap relativity, but unfortunately, relativity looks highly likely to be true based on our current assumptions. And relativity means those strange angled paths through spacetime, where by going really fast in a frame of reference time will pass differently (seems to be experimentally true for satellites with clocks in orbit!). (And yes, I know that the video seems to claim that relativity isn't the problem, but... it totally is, I disagree with the video on that.)
First thing that causality/FTL paradox diagram makes me think is that our basic understanding of causality may be inaccurate. That's the first place my brain reaches for. It's like running through an equation that you already know the answer to but coming up with the wrong answer. You know the answer you got is wrong because you know what the answer already is, you're just working through the scenario the equation presents. In life, when it comes to problems involving perception of any kind, I've learned that the first place you always want to look is at the human error factor. I'm no quantum physicist or math wizard, sure. But when you know the answer you're coming up with doesn't match the answer you know to expect, do you blame the problem or do you double check your work? Or to simplify it, when you take a measurement and then cut something to length and it doesn't work, do you check the measurement or do you check the cut length? Problem then becomes that we don't have a cheatsheet to refer back to and there's no way to run a real world version of it to see how we get to the answer. At least not yet.
There was a PBS Space Time video where the narrator proposed that the decreased progress in quantum mechanics may be due to the fact that we may have to consider a completely different outlook on how we see the universe. For all we know we might've reached a dead-end given the knowledge and mathematical formulas we have. We're trying to apply macroscopic rules onto subatomic events that we cannot properly measure, so our intuition fails us time and time again. Or as someone else said, "if your only tool is a hammer then everything looks like a nail."
So if I had a house on mars with a FTL facetime phone and was calling my friend on earth, I could communicate instantly as if we were face to face. But what if while we were FTL facetiming, we also had STL camera feeds of each other’s respective rooms? Could we then see each other in a present past and an instant present?
Very interesting video! However, a question popped up for me about the breaking of the causality rule and I can't seem to answer it myself. So, according to the rule, "the world line defines the time axis, as perceived by those following it", and thus the time slice of the STL's crew has to be parallel to the that of the observer's (that is, them; the red dash line). However, I noticed that, according to the diagram, the hypothetical STL ship takes off from Earth (I assume the point of origin within the vertical Earth's time axis is the point of departure of the ship) to send the warning of the Supernova X to Vega before the Earth(lings) actually "sees" Supernova X. Does that mean that, in this case, it is implied that "seeing" is a different event than "perceiving", and that the Earth(lings) are aware of the Supernova X radiation coming their way before they actually "see" or rather experiment its effects (if any)? Also, assuming an STL ship was ready to be launched the moment something like Supernova X was detected (not "seen" as in the diagram; something prior to that), does that mean that both an STL ship and an FTL ship are sent to Vega within the same space and relatively the same time, just in different points in time on Earth relative to the "seeing" and "perceiving" of Supernova X? Should that be the case, then both ships would have been sent to space with the same knowledge of Supernova X and the same goal, and thus when the STL ship gets to Vega, it already knows about Supernova X happening right from its departure from Earth because its purpose was to warn Vegans about that in the first place, right? My point here is, the time slice for the STL's crew is supposed to be parallel to the red dash line, and as shown in the video causality was broken when applied, but the red dash line doesn't seem to start at the right point of the Earth's time axis if anything I said makes sense, and so its origin should be the same as the one from the FTL ship if "seeing" is the same as "perceiving", which is what I understand is the case. Then the testing with the time slice would make sense since the red dash line, with its new point of origin being the star on Earth in the diagram, would roughly have the same angle as the original green line that connects Supernova X, Earth and Vega, and thus the causality would be the same as with the FTL ship, the only difference being that the STL ship would get there long after Vegans noticed the Supernova X, right? Furthermore, the red dash line, from what I understand, does not represent the actual moment when the STL ship reaches Vega: it represents how its crew perceived the time that passed from their departure from Earth until their arrival on Vega, but the real moment when they reach Vega is the red line, not the dashed one. So, the only "paradox" here would be that the crew thought they reached Vega on time to warn Vegans about Supernova X when, in reality, it happened decades or centuries ago. Shouldn't we then apply the time slice in the the red line's angle and not in the dashed one? Otherwise, if an STL ship was sent to Vega before Supernova X was detected from Earth, then the diagram would be correct as it is but the causality wouldn't be broken: the STL ship would've been sent to Vega for a different purpose other than warn Vegans about Supernova X given that the crew from that STL's ship would not know about it: it just hadn't happened yet when they departed from Earth. In that case, just like in the last scenario, the only problem would be the crew's perception of reality or knowledge about it, but not the actual events that happened around them.
@Arun PKR think about it some more dude. In the instantaneous example it's easy to see that IF a message was transmitted instantaneously, it MUST be parallel to the space line of the reference frame (because no time has elapsed). Just...it is literally the only line that's possible, because if you draw the line out denoted in the upward direction, the message will never reach earth. Also he's just paraphrasing "warp drive and causality" by Allen E. Everett linked in his description, I suggest you take a look at the paper. The math checks out, he's just making it easier to digest.
what bro why did I have to read your wall of text god damn. The ship is not going to vega to warn them about the supernova, there is no implicit or explicit causality here, the ship does indeed depart before seeing supernova x - because its purpose is not to warn vega about supernova x, it's just an abstract representation of any STL ship capable of reaching vega. (and that's the point - causality breaks with any ship travelling to any arbitrary planet sufficiently far apart in the space axis). The causality break happens when earth decides to send a FTL message to the ship, which from both earth's and the ship's reference frame, happens _after_ the ship has departed from earth.
he is just blabbing and grabbing. the reply message from the STL ship must be denoted in upward direction. but he denotes it in downward direction, therby creating paradox
@ace At first everything seemed to make sense, but upon rewinding the video for those two things I couldn't understand I just realized that, in the video, there is no distinction between actual facts and perceptions, but in reality that is what makes the whole difference for the argument doesn't it? My guess is that the original theory has more details to it than it was shown in the video and that our concerns with it are actually solved with the full explanation, but let's see if someone can give us an answer in further comments.
"It almost seems like a cruel cosmic joke that the universe be arranged such a way that we are able to look out and glimpse its wonders and yet are trapped here by the speed of light." So well said
@A Ka like you said evolution can't happen if there's nothing to evolve. Matter can not just simply appear, it has to be created, but who or what created all the matter in the universe? God did there is overwhelming evidence to support this theory, but most people are deliberately ignorant of the evidence because, if God's word (the Bible) is true eternal punishment is a consequence for those who resist the free gift of salvation Jesus offered to all and they don't like that, they don't want to know the truth because sin is pleasing.
My issue with this is the STL operates under the assumption that the crew or even a computer is capable of responding the exact same moment the message is received. Even if it was a computer setup to receive a 1 and return a 0 there's still time there for the response to be formulated and sent out
There are two possibilities. FTL is only possible between two locations that are not moving relative to each other, in which case they share the same “now”, or ftl is actually moving through the multiverse.
I'm just curious, if time is constantly moving forward as in the perspective of earth wouldn't the message be returned from the ship later in time? any clarification would be appreciated
My explanation of time paradoxes has always been that the timeline is rewritten each time. For example in Terminator, John Connor rose to be a lead through other means. After the events of the movie happen, he becomes a better leader in the future and changes appearance (genes) due to his father being different than the previous timeline.
Great presentation. I always thought FTL so far eludes us was because of the infinite energy requirements. Since it's about causality, FTL does not seem possible
There once was a young lad named Mike. Who could run faster than the speed of light. He took off one day, In a relative way, And returned on the previous night!
@J David its not necessarily impossible because both numbers of the ratio always reflect a percentage of a singular unit. basically, the 100% cap is simply the point at which division becomes multiplication. for example If I eat 200% of a chocolate bar, that simply means I ate 2 whole chocolate bars.
"The cosmic speed limit, the speed of light is so diminutive compared to a galaxy. It almost seems like a cruel cosmic joke that the universe be arranged in such a way that we are able to look out and glimpse its wonders and yet are trapped here by the speed of light. Fated to only ever peer through the bars of our cosmic prison and dream." -- This is so beautifully spoken...
Hello Sir! Time Paradox you explained resides in a slice of space and time as concluded by Eienstine. How do we validate this Paradox in reference to continuous expansion of time and space without the measure of acceleration rate?
Just wanted to put this comment and anecdotal information into the universe. Your thumbnail image for this video, I've seen a close example of it in real life. Gravitational lensing / distortions surrounding an object with blueshift at front with redshift on rear, if I would've blinked at that moment I would have missed it. That was the most mind blowing night I've ever had, while stargazing deep in the mountains (other people were with me to confirm it wasn't a dream, there was a few more physics defying events that happened that night). I wish I was better at math to dive deeper into the topic, but there's only so much time in a week (ba dum tiss). Love the video, great detailed explanations!
I so want to work with you and get a PhD. Unfortunately, I am neither a physics major nor good at physics!! But I absolutely love astronomy and everything you do on this channel.
@Equious Well, there is a lot of things you can't do beyond just that. In fact, the vast majority of things you can think of you can't do. Its pretty much infinite to 1, since imagination is limitless, but reality is EXTREMELY constricting. Every second of time virtually nothing goes exactly as it would in your best imagination, for everyone, everywhere, who ever lived. What you can do is get sort of close to what you want some of the time, if you work at it. And that is enough.
Excellent video! One question open for me is "How would the space axis look like for any FTL voyager? Would you flip it also relatively to the light speed? In that case in our frame of reference we would see their axes as inverted (meaning that they are travelling back in time?). Would a FTL traveller still see light moving always at light speed?
@MonOptiqueThe present moment I’m experiencing is not the exact same someone will be experiencing 1 light year away. You can’t just rule out observation-based physics.
If you were to “go” faster than light for even a split second, you would travel back to the moment you attempted to travel at the speed of light. Hence, why it’s a limitation and completely impossible when considering all theories.
"The present moment" is identical for everyone, everywhere in the sky of the galaxies. Traveling to the "past" or to the "future" is an idea of our brain, very imaginative. This does not correspond to reality. Sorry. Greeting from France.
In the Halo extended lore (books and etc), their use of slipspace creates time paradoxes like, constantly. It's not uncommon for a ship to arrive at it's destination hours, days, or WEEKS before it left. And everyone's collective reaction to the existence of these paradoxes is just to kinda shrug, say "hey man, don't worry about it too much," and move on
@James McQueary This is a great analogy. In the Forerunner trilogy, they call it "slipsspace debt," and there are galaxy-wide implications for pushing that slipspace debt. Objects that are bigger, move faster, or travel very long distances incur greater slipspace debt. Whenever the Halo arrays were moved, it messed up slipspace travel and FTL communications across the entire galaxy for YEARS.
A good analogy to this is: The ship is moving through a sea of molasses, the ship can move faster, but it requires a lot of power, and the molasses collects at the "front" of the ship. When the ship uses ftl, it collects molasses at the front, and when it arrives at it's destination, the molasses has to flow off the ship and fill in the empty space left by the ship, until the buildup of molasses has returned to normal levels. This molasses represents time, and when the ship uses ftl, it compresses time toward the destination, and time (molasses) from the point of departure has to flow in behind the ship fill in the "empty space". Once the ship has exited ftl and has returned to/ is returning to "normal space", the time (molasses) flows back into the "empty space". Once the molasses reconnects with itself and fills in the void, time begins flow normally again, but because time was compressed on the journey, there was no "drag" to keep track of, and the ship seems to appear at it's destination before it's departure.
@Nick Malachai The Biungie lore was great. 343 fucked it up though. Never heard of this one, though. Covenant ships were always faster so this is an odd one to throw into the mix.
@Horse Deluxe I actually like the secondary lore, for the most part, I just wish the games were tonally consistent with it. Granted, I'm a Star Wars and Transformers fan. I'm used to worse bullshit than this.
If you look at FTL as a linear speed then you probably have access to instant teleportation anyway, I feel as though acceleration and deceleration of anything traveling FTL would help alleviate a lot of confusion around space/time paradoxes. You would be looking at a lot more problems to solve with linear FTL such as matter being instantly obliterated as it instantaneously goes FTL. I like to imagine it as a function curve which starts out as STL then crosses the null line horizontally then decelerates to the same linear function of STL but below the null line. kind of like a tilda ~ I know all this is completely incorrect but hey might give someone something to think about or explain how wrong exactly i am :)
I agree. Instant FTL like teleporting would be kind of impossible. You could maybe transfer data from you to a copy of you in another location but this data would still have to be transfered from one point to another either at the speed of light or ftl somehow but never instantly. Not sure if i'm right tho
Every point in the universe has a unique energy signature. If you can create a device that could detect it and another device that could create it then you would be able to phase out of one location and phase into the location you want to be at regardless of distance.
But to transfer the data of your existence it must travel the distance. You could never make a perfect copy of you somewhere else without any travel through space and some amount of time
Bascailly, what I got from this is that as long as you don't have an STL ship traveling a significant percentage of the speed of light and using an FTL transmitter, then the odds of a paradox are bascially zero. And if we had FTL technology we probably wouldn't be using STL ships that travel at a significant percentage of the speed of light anyway. So it's a problem, but not a huge problem.
This video is an exceptional exploration of the possibility of faster-than-light (FTL) travel and messaging. The research referenced in this video is outstanding, and the music and film/TV clips used make it more interesting. The video is well researched and presented in an engaging manner. If you're interested in space travel and its possibilities, this is a must-watch! Subscribe to their channel to stay updated with their research.
Thank you for breaking my brain. I have always had a problem with relativity, but I am not an academic in such things, I'm a layman with little real understanding. This both helped me understand and broke my understanding...
Fascinating stuff. My brain feels like it wants to expand beyond the confines of my skull. I think once we understand the true nature of the universe we will better understand the possibilities and consequences of FTL.
there are no possibilities with FTL travel. FTL travel is impossible only something with zero mass can travel the speed of light. any spaceship you built to go that speed cant do it as the faster it travels the heavier it gets and then it needs more power. you would need infinate energy to get to the speed of light and that cant happen.
Correct me if I’m wrong but the paradoxes would only happen if your going FTL but if your going at 0.99 the speed of light you’d just experience what a person on plane sees to a greater extent in terms of time dilation
I love your conclusion. Its true. I think the only real way to travel in space vast distances, would be in huge colony ships embarking everything it needs to last generations until it arrives on the next planet. It would need so much abnegation. a loing term view big objectifs.
Thats actually because Hawkin is astonishingly overrated. A lot of people have described stuff he is credited with far more concisely, but his reputation, unique appearance, media buzz, and "pow science" makes everyone think he came up with things that are well known already. It disguests me that he is being credited with some kind of discovery of no causality violations, an axiom that essencially every physicist, and frankly anyone with common sense, has known for all time. Him phrasing it more "sciency" as if its some kind of profound statement is total bs.
Loved your video. Have your same feelings and hopes about it. But "Alcubierre" is a Spanish lastname. From one of our regions, the Basque Country. It's pronounced something like this "Al (like Al Copone), cu (like quality), bi (like bee), e (like elegance) and rre (like recognition). He is mexican with Spanish origins. Thank you and good luck ;)
Thanks Dr Kipping If space is expanding FTL, then we are also expanding at an FTL speed relative to everything else. Sort of like two jets traveling at 600 mph together that appear to be stationary to each other . If we were in a spaceship that somehow could halt our expansion speed, could we "travel" to another star that is in expanding space towards us?
Another possibility is whenever you travel or send message back in time, it's shift to a parallel universe. In this universe no sender in the future exists, they just receive a message/traveler from another universe. So no causuality is broken. This also goes in line with the multiverse interpretation of the quantum mechanics.
Yet again you combine scientific explanation with a thoughtful and beautiful message. Thanks for one day deciding to start doing these videos, they mean a lot to me.
The key to this explanation of FTL travel and time paradoxes seems to be the idea that a person's space axis is always a reflection of it's time axis about the null line. That is why when the STL ship travels close to the null line that it's space axis is also moved close to the null line. It isn't clear to me from this video why that is. But perhaps that is a larger and more complicated discussion.
I have the same question, why is my space axis a reflection of my time axis across the null line, if an atom is at one point in space for a period of time, according to this idea the atom would also be instantaneously at another point in space
I think the thing is that people assosiate time with the speed of light. Seeing something has nothing to do with when it actually happens. Time still exists even if you are blind
i'm wondering how photons are experiencing space and time, since they are travelling at the speed of light there fore there space and time axis are the same. the more impressive fact for me that i can see in this diagram is that if you moving away from the object you are literally travelling backwards in time for that object
I think there is a problem with the way the diagrams were drawn. The place it starts to break down (may actually be sooner but...) when the STL ship receives the message and then sends one back. It can most be seen when the message is sent instantly. The assumption is that the return message is actually received before the first message is sent. I have a problem with this. If there is a doorway where we can only view, not travel. You are on one end and I am on the other. You hold up a sign with a message. I see your message and I hold up my sign with my message. The two messages are sent instantly so the only time lag would be writing the return message. This means that the arrows that were drawn (specifically the second) are not drawn with the correct angle. Instead of the second being drawn further downward it should have been drawn upwards. I hope my description makes sense.
@Carlos Soriano I don't understand the angle of that message back to earth either. If you start with a message back to earth AT the speed of light, what would that angle be? Then go slightly faster... I do NOT think it would land you in "going backward in time" problems. I think the speed they chose is not only faster than light, it is an impossible speed that IS beyond reckoning. But if you back off that, I think the angle would be permissible. OR, if I am wrong somehow, then this would have been a better way of expressing the point: show how a lightspeed message is okay, and anything even a tiny bit faster than they is NOT ok.
@Jordan Sousa if you get a set square and put it on the space line, you’ll see the first message is going up, the second one which was instant is parallel hence it looks like it’s going down even more. Remember this is from earth frame of reference. It’s hard to wrap your head around it for sure.
@Carlos Soriano I wouldn’t say I’m the smart one. The reply from the ship has to be parallel with its own space line and the diagram is drawn from earth reference frame.
Omg this diagram finally explained why and how space and time are connected. Thank you so much. I always thought I understood this concept but I was just repeating info not fully grasping it.
Honestly, the most depressing thing to think about is that if there is a form of FTL travel developed in the future, literally none of us will be alive to see it.
It's been too long since I learned how reflecting lines about different axis' works; how does the ftl comm reply at 18:10 result in that line, rather than its reflection about the time axis (since it's traveling the opposite direction in space, like described at 8:53), which would then not break causality since the comm will still be traveling higher up the time axis rather than back down?
This whole thing perplexes me too, but I found that his explanation at 19:10 was cool. The pink line going back to earth to say “don’t send the message” would have to travel parallel to the space axis of the STL ship, as the FTL message would travel instantaneously and can thus not travel through time in the perspective of the STL ship
Sounds like you have given up, I don't have the answer to FTL but I can tell you that we aren't looking at it from the lens we need too. Your null lines in the diagram sure did look a lot like an imaging scope for sound fields. It got me to ask how if it at it could be related, the answer I came up with is interesting if you'd like to reach out to me. Keep the quest alive friends!!
i think the problem is reaching the speed of light itself, not going over, from my physics recollections, the problem is to reach the speed of light your ship reaches limitless mass, hence the need for limitless energy, but if by any chance we skip this threshold, maybe it becomes possible...
What is most beautiful about this video - is actually what it has done to the comments section. Look at all the wonder, the questions, the curiosity, the debate. All these wonderful human beings trying to discover - this is what I love most about humanity, we're all in this thing together :)
Consider this. If we use the warp drive, the answer to this seeming paradox lies in the means used for faster than light travel. You see, the ship itself is not actually moving fast than light. Space is moving around the ship faster than light. It is shrinking the space between in order to move between Earth and Vega. If you correct your graph to account for the warping of space, I think that you will find that it puts the procession of events into the correct order.
I was thinking at something similar. Not sure if I'm wrong, but maybe the "Vega receives warning" point was placed too far away from "Vega sees X". What if the FTL message was sent from "Earth sees X" instantly towards Vega? It would arrive at the same point where the STL ship would arrive if it left earth before the message was sent. The message is still sent faster than light, but not exaggeratedly fast like in the example given in the video. In this way, it wouldn't break the logic of events if you slide the time slice parallel to the STL's ship's space axis AKA earthling perceived time.
I’m in favor of the conclusion that if we encounter “paradoxes” in a scientific thought process we should consider that the concept is flawed. However, I would point out that the chart has problems when using the STL craft and it’s time slice. Even if one buys that the STL time slice is the correct angle here, it still matters where the craft is on that slice. The crew doesn’t get to instantly “know” when Vega sees things. You’d have to allow time for Vega to send the signal to the craft and by then the light from the super nova might have already reached the ship. In addition, the ship’s movement through space over the course of the events it does perceive would affect the value of this visual.
@Hammertime Here's a good question: where is the omniscient pov's time line? Maybe trying to have an objective perspective on a process that is quite literally relative is the problem here; trying to introduce a variable that is antithetical to the experiment. The explanation is flawed because it fails to address this; we have an objective point of reference: the light line. If that is the case, information cannot move against the vectors of the light lines, thus only up and across, regardless of your perspective.
juan abee Empirical evidence tells us that physical laws are consistent as far as we can see. We can sense and measure a lot about the observable universe. So what I'm saying is that the assumptions are not about the Physics. Dark Matter is point of discussion though, but its gravitational effects are known, and its source is being narrowed down and homed in on.
Thinking about this more. I'm pretty sure the result is due to the "instantaneous" message not being instantaneous in all reference frames. In this diagram it's instantaneous in the sender's reference frame, but not in the recipient's. That might be the correct as far as special relativity goes. But then again, before special relativity everyone thought the speed of light was different in different reference frames and no one considered that it could be the same in all reference frames. What does the result look like if we assume faster than light messages are the same speed in all reference frames, just like we assume with light? I don't think this would break causality. Though it might break other things. I need to think about it more.
Well.. sometimes there's circumstances that create two or more different speeds of sound. So I wonder if there's circumstances that could create different speeds of light? I'm postulating if you could cause variable light speed then you could also have variable time. But now wait a minute. Time is more related to gravity. I'm going to have to think about it some more.
I have always been fascinated by this topic and this video is hands down the best explanation I've ever seen and breaks things down to the point that even I can understand the basic concepts of it and felt compelled to comment on youtube for the very first time ever, with some questions. Earlier in the video, it was stated that "instantaneous travel was the most extreme FTL possible" with a pink line that went straight across the space axis. But later in the video, a FTL message from the STL ship sent back to Earth was assumed to be going back in time. This seems contradictory to me. Why wouldn't the limit be instantaneous travel here also, going across the space axis back to Earth? Why wouldn't FTL still go forward in time (arrow pointing upwards), back to Earth, but just faster than STL? From my limited understanding, assuming that the limit for a message to be sent to an STL (or FTL) ship is instantaneous, the message sent back would also be limited to instantaneous travel time. Why do we assume that we can go back in time in any of these scenarios?
I like to think that time is like a book. We each have our own unique book, everything is already written from start to finish, but we read one page at a time. If you could go back some pages, (back in time) the simplest change would mean that the script has changed, therefore you would no longer be in the same book. In this analogy, paradoxes are irrelevant.
I think as soon as something like FTL is achieved, we'll soon learn that there is some other, infinitely stranger arbitrary limitation way beyond our grasp that we could never have even conceived of before. I have dreams about it all the time, since I was a child in fact.
Logically, you could replace "light" with "sound" and "see" with "hear", and FTL with FTS etc. and by the exact same logic and graph, nothing can go faster than the speed of sound.
I'm not able to understand why the STL ship's space line (dotted red line) is at a lower angle than the ship's time (solid red line). Not saying you're , I may have missed something and would love to understand this model. Edit: I see now why the model works like this, as it's explained that the space line is just a flipped time line over the 45° angle.
14:50 I really tried to understand and comprehend this, was fine all the way up to the dotted stl axis..and I struggled :( rewatched and still can't get it. 😔 Edit: I watched the rest and as Marty Mcfly once said, (almost) 'I guess I'm just not ready for this stuff yet' 😅 A fascinating and intriguing topic, however.
The diagram is wrong it is missing some variables. Time is relative for each object even the message itself, at 14:50 it doesn't say amount of time for the ship to receive the data OF VEGA. So even if Vega at that moment sent message FTL, the ship would still receive it in it's relative time. Example is, the message of Vega to the ship itself would have 'sense' of 1 second traveling, BUT when it reaches the ship, the time passed for the crewmembers would be a lot more.
@FantaWriter I actually really like the Brian Green example, using a loaf of bread where time is described in a series of infinite moments each one a slice of bread, bread being the space. I understood the relativistic logic there.
I don't think this diagram is even accurate, since the order of events from the "crews" perspective shows that Vega Receives Warning before they even leave Earth, but they would have the same time slice as Earth until then.
It was all very nice explained and I understood almost all of it. there is only one thing I am trying to figure out. in the Diagram, why is the Space axis for the STL ship at an acute angle? wouldn't that mean that, even though they are traveling STL for us, it seems for them as though they are traveling faster than light? because, for them they are closer to the space axis than the time axis. I hope my question is understandable.
I always love the very grounding and philosophical thoughts proposed in these videos along with the theory. Really helps to place the science and the importance of these studies in a broader sense and why or why not humanity should pursue them.
Our understanding of the physics of our universe is rudimentary, at best. People once truly believed that it was impossible to break the sound barrier.
Since spacetime is moving FTL relative to us, we are also moving FTL relative to those same parts of spacetime. The reason it doesn’t create paradoxes is because the speed limit of light only applies to things that move THROUGH space, it doesn’t apply to space itself. So when we look at a distant galaxy moving at a speed that seems to be FTL, the galaxy isn’t actually moving, or at least it’s moving much slower than it appears. One way to envision this is to think of 2 ants on a balloon. An Ant might only be able to walk 1 inch a second, but if you blow up the balloon as they walk apart, they could end up 10inches apart after 2 seconds because the surface of the balloon is expanding so fast, even though they are only walking 1in/s.
Before we move anything at the speed of light, we need to figure out how we would transport people at such speeds. The human body would be obliterated if we tried. I think that’s an even more difficult if not impossible task than actually reaching the speed of light.
Something people are struggling with is why the line is moving downward in the STL Ship example with the FTL transmission. It's understandable, given how unintuitive physics is with common sense. Im not 100% sure either whats exactly going on, but I think I can grasp enough to put it in laymans terms. So when the STL ship is moving through space, time around it is dialating according to how fast you move through space. The closer to the speed of light you are, the faster time seems to move around you as space literally speeds by. The problems begin when you reach the speed of light. What happens? Firstly, you are now past the speed of light. Think of a car. You know how when a car drives by you at the same speed, it almost looks like it's not moving at all, even if you know it is? That's what would happen to time and space around you as you perceive it. To light itself. Now consider what happens when you begin to outspeed light. It would move. But not forwards ahead of you. But behind you. Space and time would be so slow by your perspective that it would begin to move backwards, literally. The closer you get to another object, the further back in time that space will go. Atleast, in theory. There's definitely alot more to this, but don't feel bad if you can't figure it out. This is literally the science people spend their entire lives attempting to solve. Understanding the fundamental underworkings of our literal existence isnt something you just happen to have the ability to do. You are flesh and blood, and your instincts as well as common sense do not apply to the chaotic, esoteric universe that lets us live in it. In short, FTL might be fundamentally impossible because of physics, the theory of relativity, and paradoxs. To break a hardset rule might just not be physically possible, and we wont know for certain UNTIL we can figure out why Quantum Mechanics and Relativity don't mesh perfectly. Hope this helps, any physicists feel free to come and tell me if Im wrong somewhere. My understanding is very limited, so my word isnt law here.
Outstanding! FTL was always a dream since watching Star Trek as a kid. The fact that we can glimpse these wonders of the universe as water filled meat sacks is truly amazing. Even if it isn’t possible, I appreciate that logic as to why is isn’t possible. Space is big. We’re living in an age of high definition discovery.
Wouldn't call humans just water filled meat sacks. We are an outstanding species that just appeared shortly on earth. Our intelligence and consciousness is a God's given gift truly. In the future I believe we'll be able to change universe to our fit
The idea of the multiverse fixes this. The paradox is simply avoided by the ship's reply back to earth creating a new reality. Now there's 2 earths were one never turns off the FTL machine and one where it does
If the idea is to work together for something beyond that is attainable by our own mortal timeline, for the benefit of the next generation or of the survival of humanity, then the ants and the bees have already beaten us to it. The movie Interstellar has given us this message in its final scenes.
@The Great Hadoken Your negation is on a frame that is Material and physical. My comment was actually framed in the philosophical, spiritual and cultural context. Of course you can easily squash those bugs, why then did I say they are better? well, there's the difference in the framing of the context. What I am highlighting is their superiority in organization, perhaps maybe their structured governance, class function and collective utilitarianism. But then of course the hive-mind, swarm and collective principles are required which are not attributes prescribed by nature to humans and even other advanced species. Communists tried to emulate the principles to a certain degree, but never effectively and consistently like the insects do. Maybe it only works for smaller organisms that can produce their own materials and not need more than what they personally utilize. As compared to capitalizing on fellow smaller organisms for enterprise and bucketloads of camel dung currency or trade resource. I cant say for certain, but maybe. just maybe, we wont be able to break the next barrier of civilization development unless we adopt a culture similar to those bugs. All of those goodness and yes, of course, you can easily squash them and burn them and they only get to space if you put them in your pockets or your drawers.. they don't have their own rockets, their weapons are even their own teeth! Imagine going to war with UK, and the geneva convention prohibits use of any other weapons of war but your bare unjacketed, unbrushed Teeth! UK would lose i know but that was the joke. lol These bugs even have to live close to human homes to conveniently find food and water. I hope you see the miss now. :D In short, between my comment and your counter, there really was no intercept. Like I aimed for Andromeda through the dark side of the moon, but from the same moon on the brighter side, your aim was back to the earth. No linear intercept in idea, vector, frame and context, whatsoever. Nevertheless, I agree with all your physical assessments of how the world is naturally existing at this very moment in time. ;) Seriously though, thank you for sharing your thoughts. I appreciate people who think.. unlike most of the modern people today.
According to the graph, instant communication would be possible between two points with the same space axis. This would make it impossible for the moving ship to send an FTL message to either planet. It would be impractical since the planets would have to be perfectly stationary relative to each other, and gravity could screw that up easily, but it's theoretically possible according to this video.
Interstellar is a great movie and it actually got me wanting to go to space, im 15 so i have my whole life ahead of me and i can't wait to see if i am actually able to accomplish my dream
Best explanation of time travel paradoxes I've seen in a long time, thank you for this! I feel so amazed that on one hand we can theorize and explain stuff like this yet a lot of people will still doubt that we ever went to the moon.
@Kayla Leave They left laser reflectors on moon to calculate exact distance from it. When you throw lasers on the reflectors at a perfect angle, the laser will bounce off from the reflectors on the moon and reach Earth. This can also be served as a proof that if laser is bouncing back at a perfect angle from moon to Earth, then surely someone went to moon and left a mirror at a perfect angle. And I'm pretty sure it was us humans who did that.
Because he uses theory of relativity which relates to light in time and space and attempts the correlates to different objects in time and space then takes a hypothesis vessel in time and space. Then attempt come up some silly idea that the FLT vessel is able to go another plant drop for a message has some how caused some break in cause and effect has been shown at all. All he did was show a hypothesis and bad one that. We don't have FTL we have no idea the relationships between traveling to such objects. We don't even understand time and space yet. Einstein pointed out that space isn't nothing but something and keep thing it is nothing. It bend it warps it does stuff we can even wrap our heads around yet and his guy is make bold statement like this. What is time? It is tied to space but how? We haven't tried to find that answer. If you say time travel paradoxes then your also saying a space travel paradoxes because they are just like electromagnetism you can't not part one from the other. Have you thought that maybe as you past the speed of light time goes backward because it stops when you hit light speed? He never speaks of this fact. So basically those people traveling at light speed do get there in a split second or did you for get relativity also apples to how one see time pass.
I don't see how causality is broken here, because the STL ship isn't actually affected by Vega receiving a warning. Even if Vega were to message the ship at the same speed as their incoming message, the ship would be notified of said information (say plans to evacuate or whatever) around the time of the supernova. They would be unable to effect changes to the outcome. The only ones capable of changing the outcome would potentially be Vega - this is the thing that seems causality breaking to me. What if they could prevent the supernova? Then they would never have been warned, right?
I like how he predicted every point where I got confused or skeptical and delivered a good answer without me ever asking anything lol About the talk in the end about exploration without FTL, it was quite poetic, but individuals can actually experience it one day and travel to many stars, considering there is no barrier in the laws of physics that say living things can't last for billions of years. More than that, the way in which time is perceived can be drastically modified, where a million years travel can feel like a mere hour. Just imagining human-like consciousness in a digital substrate is enough to see how this things are possible
@Mia yeah in theory maybe. but in reality you would need infinite speed or infinite gravity to get infinite time dilation afaik. also if you want to park hubs "outside of time" you would basically have to park them almost inside the black hole which would be almost impossible and starting from it would take a fuckton of fuel because you have to overcome the gravity.
Time dilation can approach infinity. Through time dilation it is theoretically possible to make a billion-year trip feel like a year. I imagine we would have hubs "outside of time" parked at black holes. Ignoring the radiation problem for now haha. The hubs would keep humanity somewhat cohesive, but travel outside the hubs would be one-way trips. I imagine we could use the black holes to accelerate ships to insane speed. Theoretically, occupants can travel across the galaxy within a human lifespan. They could keep the hubs informed, but communication from the hubs would be impractical. We wouldn't be able to overcome the expansion of the universe with this method though. This is more of a story idea, but I think it's physically possible. There isn't much to gain commercially either so this happening, in reality, is slim without a change in our culture.
@Georgi Rusev *Absolutely illogical what you claim* ! Absolutely ... As soon as you start slowing down, almost all your benefits are lost ... By the way ... *You can never* reach the "edge" of the Universe! Never! (At most, if you turn it to self ...) As for, it's also nonsense ...
It seems to me like the "protagonist" of causality is the one with agency. It would seem more intuitive, if the realities that the STL ship intercepts FTL message and sends a reply, and that Earth receives the reply before sending the message exist simultaneously. Of course, this could have some kind of crisis "prophecy" applications, wherein you just have to assume that unsolicited messages have a context that exists from the STL ship's perspective, but are absent in your own. It might be a good way to undo or mitigate cosmic catastrophes, to surround your solar system with detection satellites equipped with FTL relays. You would just be in your office and you would receive a message saying "Don't tell anyone about the supernova about to happen." They would later land and rendezvous and report that you had previously send a message stating that a supernova happened, do they sent one back in time to tell you not to bother. In a way the STL ship would be its own pocket of causality, unrelated to the wider universe. To suppose this somehow breaks the universe would suppose any form of clairvoyance also does so. I'm aware the latter is fantasy, but that's also what's said of sufficiently advanced technology.
Man great word choice in the introduction, you play beautifully with words and caught my attention with this awesome introduction so much that i just had to write it in a comment, you have a new subscriber:)
So since most of this is theory and assumptions I will question how this STL ship is capable of picking up non direct signals and messages at the speed of light (I imagine that FTL messaging would be more of a P2P affair than standard signals). Because while yes *technically* effect happens after cause but only if they receive this information at or faster than the speed of light. Which means that from the perspective of the crew, yes its a paradox, but its the same as if I got an email telling me about an oil spill and then got a newspaper that told me about how an oil tanker lost control and may or may not miss an island. In theory I could perceive this as a paradox if I chose to believe the newspaper to be more up to date than the email.
So if Vega can get a warning can get a warning THEN later will see it, that means theoretically as soon as you get the warning you can travel at FTL to prevent it from happening thus going back in time
imagine you are somewhere else in the universe. now imagine you wanted to travel here. there you go. just saved a hell of a lot of time energy and effort.
What a wonderful episode. I really loved the prespective you provided at the end. To view this inate limitation of sub-FTL speeds as a blessing, because it might compel us to live for future generations beyond ourselves. Beautiful stuff ^_^
So if alcubierre was inspired by Star Trek does that mean the writers of Star Trek accidentally invented a fake explanation for how to do FTL that just happened to actually be legit or did they get consultation from physicist who told them to word warp drive like that
If speed equals distance over time, speeds anywhere near c will literally be FTL. Another funky flaw in FTL is that once at c it should take zero energy or food stocks or oxygen to maintain their travels since time stands still🤯
![SCREAMS SCREAMS and MORE SCREAMS [Fears To Fathom: Norwood Hitchhike]](http://i.ytimg.com/vi/dT6taoucBX4/mqdefault.jpg)
I like to imagine that as soon as we discover FTL and break spacetime, the simulation crashes and the higher beings are annoyed they have another bug to fix
@Derek2k First of all, the comment is a joke.
Second, even if the matrix was never created, I think people would still have the theory that we live in a simulation. The theory isn't even mainly based on the matrix, since there are records of it hundreds of years ago. Get your facts straight before commenting next time.
@Derek2k It seems difficult for many people to let go of the dream of FTL. The basic fundamental way the universe is constructed runs counter to the stories we have told ourselves. It's as if the characters on the page of a novel wanted to jump out of the medium of the printed book into a world in which we have no correlation.
The fact 1.2k ppl liked this makes me lose faith in humanity. Do y’all truly believe we are living in the matrix or something. I wonder what y’all would think if the matrix movie was never created.
I landed at the same "strict rules" conclusion back in 2007 when designing a sci-fi setting with FTL. I borrowed a bit from Douglas Adams and ended up with a version similar to one you hinted at. That any attempts to perform an action which would result in a paradox would be met with increasingly unlikely events to prevent it from occurring in the first place. Thus, before sending any FTL comms, or engaging in certain kinds of travel, you have to draw the light cones and think through the implications as shown in your video. Thanks for putting this together. It was nice to see someone think through the same things and tie it into a neat package.
I am doing a copy and paste from a quick thought I had.
"Just spitballing here, because I am not a physicist nor time traveler, but perhaps it needs to be viewed in other dimensions rather than with a 2d graph.
Say for example someone makes a device that in theory can send an FTL message. They turn it on and send a message, but nothing happens so they think it didn't work. However thinking in the infinite universes model the senders universe continued on it's time line, but the message was received in a multitude of parallel universes. They have zero clue as to where the message came from, but they received it none the less.
Or perhaps the universes have a way of keeping things tidy, so too speak. So when the FTL message is sent, how do I say this, the entire universe is sent and is no longer where it was in time. Thinking in terms of infinite universes perhaps there are as many, call them anti universes (empty spaces) in the big empty. So the universe itself where the FTL message originated instantly fills the space where the message is received thus avoiding some weird entanglement of timelines.
Sure there might be some side effects such as the Mandela effect, but that is price we pay in order to have FTL."
Congratulations, you had my complete attention to the entire 25 minutes. Very well done video and explanation. Super interesting
One small thing: if the message is traveling in a different time perspective than the ship, in what time perspective will this ship be able to decode it? (a reference to Orson Scott Card's books about Ender). I think this is not considered in your diagram.
Cosmological and chronological paradoxes are so interesting, rather enjoyed listening to this more than I'd expected.
This is hands down one of the best channels ever! Love each and every video more than the last! Bravo and please keep doing what you do, it's voices like yours that truly touch peoples hearts and minds, revealing questions they never knew they were interested in knowing the answer to! If that makes sense, lol!
Led me to think
Does anyone realize how crazy it is that we can even theorize something like this
@Random Cubing And thanks to all of the incredible mathematicians that got Einstein started.
Does anyone realise that between us in this comment we might have the same ideas the same way of thinking or even the same habits? So how some people tell and even think that there is no life out there, maybe a copy of our planet or better or even in worse sape, and think that those sapes could possibly be our planet if we continue to live as we do or if we changed some things to the way we live right now. We couldn't know if we'd achieve a better or worse future aside the statistics.
@Joseph Preston lmao what that's dumb we don't have FTL
According to bob lazar we already have this tech. I’d imagine by now we’d be able to reverse engineer it. Best believe there’s going to a be a huge tech leap relatively soon.
I would posit that it is possible it's just all about frames of reference. You would not be able to affect anything in your personal referential past. You could observe it, but not change it. I think the diagram is off in using the frame of reference for the STL ship as the "speed" of their FTL message would be significantly "faster" than the message from Earth. The correction for this means that their message would NOT arrive prior to that of the sent message. (On the graph their message would appear to them (could they see the graph) to curve upward past the message point. Using star trek terms if you fired off a message at warp 1 its not going to travel at (warp 1 + full impulse) simply because you were going at full impulse. Basically this graph "forgets" that for all of the pink FTL lines, the straight "space" line is not straight. For them it is a curve, so if you factor that in and the flatten it back out it shouldn't violate causality. I am probably wrong somewhere, it's 2 in the morning...
The diagrams do not seem correct as sending a message faster than light could not arrive before the original STL ship left.
I think he is mixing up time travel and speed of light which are 2 different things.
I think you're correct. Basically, the means of "propulsion" that an alcubierre drive or "warp" drive would use manipulates space. You are not traveling ftl in terms of momentum, you are bending space so as to take a path shorter than the light is taking. I think technically you aren't moving, space is.
For the record, I think that an alcubierre drive is impossible because you need imaginary materials. But since the video is referencing that as the means of propulsion, the argument, as I understand it, that there would be causality issues is incorrect.
It may be right or wrong but the fact that it is showing 4 dimensional space-time on a 2 dimensional graph, it's like trying to show a 3D cube in 1D, it's simply not doable or at least it seems to me. From what I learned we are able to show a cube on a 2d sheet just because we are able to visualize the depth of the image and draw a "line behind the lines" that how we create 3d in short we are able to circumvent one dimension by imagining it so 4d can be shown in 3d, 3D in 2D, 2D in 1D, jumping from 4D to 2D doesn't make much sense and many things may not match like they should. That I think is the main problem here that there is just no way that he could show what he wants on 2D sheet. Rather than FTL I am more convinced by Einstein-Rosen bridges theory beacuse from what I know they go through additional 4th dimension of space there for not creating this paradox if its true.
(sorry for mistakes if any english isn't my first language)
@Peter Ingraham no, what I am implying is that this graph is uses a straight line (thus treating it linearly) vis a vis space whereas the whole concept discussed involves bending or folding space. I do not think relativity presents a problem as I have discussed as I believe it sorts itself put if you discount momentum and the standard rules that apply to speed and motion as you would have to when folding space itself. Similarly to how the rules change when you approach a black hole they would change when you folded space. As such, this graph assumes that if they are traveling at (using star trek references just for ease of discussion) warp 1 and fire of a beacon at warp 1 it will be traveling at warp 2. It will not. I posit that folded space travel is a definite limiter such that you cannot increase the speed simply by initiating a launch from something going at speed. As such it would APPEAR to curve away from the perspective of the FTL ships view on the graph IN ACCORDANCE WITH RELATIVITY. Whereas it's not actually making a curve on the graph because the graph treats space as linear and FTL travel does not.
Saying that "the line is not straight" and implying it should be straight is basically equivalent to saying "relativity is incorrect." Now, you can have FTL travel AND causality if you scrap relativity, but unfortunately, relativity looks highly likely to be true based on our current assumptions. And relativity means those strange angled paths through spacetime, where by going really fast in a frame of reference time will pass differently (seems to be experimentally true for satellites with clocks in orbit!).
(And yes, I know that the video seems to claim that relativity isn't the problem, but... it totally is, I disagree with the video on that.)
First thing that causality/FTL paradox diagram makes me think is that our basic understanding of causality may be inaccurate. That's the first place my brain reaches for.
It's like running through an equation that you already know the answer to but coming up with the wrong answer. You know the answer you got is wrong because you know what the answer already is, you're just working through the scenario the equation presents.
In life, when it comes to problems involving perception of any kind, I've learned that the first place you always want to look is at the human error factor.
I'm no quantum physicist or math wizard, sure. But when you know the answer you're coming up with doesn't match the answer you know to expect, do you blame the problem or do you double check your work?
Or to simplify it, when you take a measurement and then cut something to length and it doesn't work, do you check the measurement or do you check the cut length?
Problem then becomes that we don't have a cheatsheet to refer back to and there's no way to run a real world version of it to see how we get to the answer. At least not yet.
There was a PBS Space Time video where the narrator proposed that the decreased progress in quantum mechanics may be due to the fact that we may have to consider a completely different outlook on how we see the universe. For all we know we might've reached a dead-end given the knowledge and mathematical formulas we have. We're trying to apply macroscopic rules onto subatomic events that we cannot properly measure, so our intuition fails us time and time again. Or as someone else said, "if your only tool is a hammer then everything looks like a nail."
your level of explanation, and competence is amazing. You show great quality passion, high enthusiastic and love for astrology.
Astrology ≠ astronomy. Big difference.
So if I had a house on mars with a FTL facetime phone and was calling my friend on earth, I could communicate instantly as if we were face to face. But what if while we were FTL facetiming, we also had STL camera feeds of each other’s respective rooms? Could we then see each other in a present past and an instant present?
Very interesting video! However, a question popped up for me about the breaking of the causality rule and I can't seem to answer it myself.
So, according to the rule, "the world line defines the time axis, as perceived by those following it", and thus the time slice of the STL's crew has to be parallel to the that of the observer's (that is, them; the red dash line). However, I noticed that, according to the diagram, the hypothetical STL ship takes off from Earth (I assume the point of origin within the vertical Earth's time axis is the point of departure of the ship) to send the warning of the Supernova X to Vega before the Earth(lings) actually "sees" Supernova X. Does that mean that, in this case, it is implied that "seeing" is a different event than "perceiving", and that the Earth(lings) are aware of the Supernova X radiation coming their way before they actually "see" or rather experiment its effects (if any)? Also, assuming an STL ship was ready to be launched the moment something like Supernova X was detected (not "seen" as in the diagram; something prior to that), does that mean that both an STL ship and an FTL ship are sent to Vega within the same space and relatively the same time, just in different points in time on Earth relative to the "seeing" and "perceiving" of Supernova X? Should that be the case, then both ships would have been sent to space with the same knowledge of Supernova X and the same goal, and thus when the STL ship gets to Vega, it already knows about Supernova X happening right from its departure from Earth because its purpose was to warn Vegans about that in the first place, right? My point here is, the time slice for the STL's crew is supposed to be parallel to the red dash line, and as shown in the video causality was broken when applied, but the red dash line doesn't seem to start at the right point of the Earth's time axis if anything I said makes sense, and so its origin should be the same as the one from the FTL ship if "seeing" is the same as "perceiving", which is what I understand is the case. Then the testing with the time slice would make sense since the red dash line, with its new point of origin being the star on Earth in the diagram, would roughly have the same angle as the original green line that connects Supernova X, Earth and Vega, and thus the causality would be the same as with the FTL ship, the only difference being that the STL ship would get there long after Vegans noticed the Supernova X, right?
Furthermore, the red dash line, from what I understand, does not represent the actual moment when the STL ship reaches Vega: it represents how its crew perceived the time that passed from their departure from Earth until their arrival on Vega, but the real moment when they reach Vega is the red line, not the dashed one. So, the only "paradox" here would be that the crew thought they reached Vega on time to warn Vegans about Supernova X when, in reality, it happened decades or centuries ago. Shouldn't we then apply the time slice in the the red line's angle and not in the dashed one?
Otherwise, if an STL ship was sent to Vega before Supernova X was detected from Earth, then the diagram would be correct as it is but the causality wouldn't be broken: the STL ship would've been sent to Vega for a different purpose other than warn Vegans about Supernova X given that the crew from that STL's ship would not know about it: it just hadn't happened yet when they departed from Earth. In that case, just like in the last scenario, the only problem would be the crew's perception of reality or knowledge about it, but not the actual events that happened around them.
@Arun PKR think about it some more dude. In the instantaneous example it's easy to see that IF a message was transmitted instantaneously, it MUST be parallel to the space line of the reference frame (because no time has elapsed). Just...it is literally the only line that's possible, because if you draw the line out denoted in the upward direction, the message will never reach earth.
Also he's just paraphrasing "warp drive and causality" by Allen E. Everett linked in his description, I suggest you take a look at the paper. The math checks out, he's just making it easier to digest.
what bro why did I have to read your wall of text god damn.
The ship is not going to vega to warn them about the supernova, there is no implicit or explicit causality here, the ship does indeed depart before seeing supernova x - because its purpose is not to warn vega about supernova x, it's just an abstract representation of any STL ship capable of reaching vega. (and that's the point - causality breaks with any ship travelling to any arbitrary planet sufficiently far apart in the space axis).
The causality break happens when earth decides to send a FTL message to the ship, which from both earth's and the ship's reference frame, happens _after_ the ship has departed from earth.
Nerd
he is just blabbing and grabbing. the reply message from the STL ship must be denoted in upward direction. but he denotes it in downward direction, therby creating paradox
@ace At first everything seemed to make sense, but upon rewinding the video for those two things I couldn't understand I just realized that, in the video, there is no distinction between actual facts and perceptions, but in reality that is what makes the whole difference for the argument doesn't it? My guess is that the original theory has more details to it than it was shown in the video and that our concerns with it are actually solved with the full explanation, but let's see if someone can give us an answer in further comments.
"It almost seems like a cruel cosmic joke that the universe be arranged such a way that we are able to look out and glimpse its wonders and yet are trapped here by the speed of light." So well said
@A Ka myths are halt true.
@A Ka like you said evolution can't happen if there's nothing to evolve. Matter can not just simply appear, it has to be created, but who or what created all the matter in the universe? God did there is overwhelming evidence to support this theory, but most people are deliberately ignorant of the evidence because, if God's word (the Bible) is true eternal punishment is a consequence for those who resist the free gift of salvation Jesus offered to all and they don't like that, they don't want to know the truth because sin is pleasing.
Yup, dem peepz in da Bootes Void are much luckier cos ignorance is bliss.
@Literally a 442nd clone trooper with a carrot 💯
My issue with this is the STL operates under the assumption that the crew or even a computer is capable of responding the exact same moment the message is received. Even if it was a computer setup to receive a 1 and return a 0 there's still time there for the response to be formulated and sent out
There are two possibilities. FTL is only possible between two locations that are not moving relative to each other, in which case they share the same “now”, or ftl is actually moving through the multiverse.
I'm just curious, if time is constantly moving forward as in the perspective of earth wouldn't the message be returned from the ship later in time? any clarification would be appreciated
My explanation of time paradoxes has always been that the timeline is rewritten each time. For example in Terminator, John Connor rose to be a lead through other means. After the events of the movie happen, he becomes a better leader in the future and changes appearance (genes) due to his father being different than the previous timeline.
Great presentation. I always thought FTL so far eludes us was because of the infinite energy requirements. Since it's about causality, FTL does not seem possible
There once was a young lad named Mike.
Who could run faster than the speed of light.
He took off one day,
In a relative way,
And returned on the previous night!
Very funny 🤣
@J David its not necessarily impossible because both numbers of the ratio always reflect a percentage of a singular unit. basically, the 100% cap is simply the point at which division becomes multiplication. for example If I eat 200% of a chocolate bar, that simply means I ate 2 whole chocolate bars.
@J David improper fractions say otherwise
"The cosmic speed limit, the speed of light is so diminutive compared to a galaxy. It almost seems like a cruel cosmic joke that the universe be arranged in such a way that we are able to look out and glimpse its wonders and yet are trapped here by the speed of light. Fated to only ever peer through the bars of our cosmic prison and dream." -- This is so beautifully spoken...
Hello Sir! Time Paradox you explained resides in a slice of space and time as concluded by Eienstine. How do we validate this Paradox in reference to continuous expansion of time and space without the measure of acceleration rate?
Just wanted to put this comment and anecdotal information into the universe.
Your thumbnail image for this video, I've seen a close example of it in real life. Gravitational lensing / distortions surrounding an object with blueshift at front with redshift on rear, if I would've blinked at that moment I would have missed it. That was the most mind blowing night I've ever had, while stargazing deep in the mountains (other people were with me to confirm it wasn't a dream, there was a few more physics defying events that happened that night). I wish I was better at math to dive deeper into the topic, but there's only so much time in a week (ba dum tiss).
Love the video, great detailed explanations!
I so want to work with you and get a PhD. Unfortunately, I am neither a physics major nor good at physics!! But I absolutely love astronomy and everything you do on this channel.
@Equious Well, there is a lot of things you can't do beyond just that. In fact, the vast majority of things you can think of you can't do. Its pretty much infinite to 1, since imagination is limitless, but reality is EXTREMELY constricting. Every second of time virtually nothing goes exactly as it would in your best imagination, for everyone, everywhere, who ever lived. What you can do is get sort of close to what you want some of the time, if you work at it. And that is enough.
The only thing you can't do is travel faster than light!
Excellent video! One question open for me is "How would the space axis look like for any FTL voyager? Would you flip it also relatively to the light speed? In that case in our frame of reference we would see their axes as inverted (meaning that they are travelling back in time?). Would a FTL traveller still see light moving always at light speed?
@MonOptiqueThe present moment I’m experiencing is not the exact same someone will be experiencing 1 light year away. You can’t just rule out observation-based physics.
If you were to “go” faster than light for even a split second, you would travel back to the moment you attempted to travel at the speed of light. Hence, why it’s a limitation and completely impossible when considering all theories.
"The present moment" is identical for everyone, everywhere in the sky of the galaxies.
Traveling to the "past" or to the "future" is an idea of our brain, very imaginative.
This does not correspond to reality. Sorry.
Greeting from France.
In the Halo extended lore (books and etc), their use of slipspace creates time paradoxes like, constantly. It's not uncommon for a ship to arrive at it's destination hours, days, or WEEKS before it left. And everyone's collective reaction to the existence of these paradoxes is just to kinda shrug, say "hey man, don't worry about it too much," and move on
@James McQueary This is a great analogy. In the Forerunner trilogy, they call it "slipsspace debt," and there are galaxy-wide implications for pushing that slipspace debt. Objects that are bigger, move faster, or travel very long distances incur greater slipspace debt. Whenever the Halo arrays were moved, it messed up slipspace travel and FTL communications across the entire galaxy for YEARS.
A good analogy to this is:
The ship is moving through a sea of molasses, the ship can move faster, but it requires a lot of power, and the molasses collects at the "front" of the ship.
When the ship uses ftl, it collects molasses at the front, and when it arrives at it's destination, the molasses has to flow off the ship and fill in the empty space left by the ship, until the buildup of molasses has returned to normal levels.
This molasses represents time, and when the ship uses ftl, it compresses time toward the destination, and time (molasses) from the point of departure has to flow in behind the ship fill in the "empty space".
Once the ship has exited ftl and has returned to/ is returning to "normal space", the time (molasses) flows back into the "empty space".
Once the molasses reconnects with itself and fills in the void, time begins flow normally again, but because time was compressed on the journey, there was no "drag" to keep track of, and the ship seems to appear at it's destination before it's departure.
@Nick Malachai The Biungie lore was great. 343 fucked it up though. Never heard of this one, though. Covenant ships were always faster so this is an odd one to throw into the mix.
@Horse Deluxe I actually like the secondary lore, for the most part, I just wish the games were tonally consistent with it.
Granted, I'm a Star Wars and Transformers fan. I'm used to worse bullshit than this.
I think there's definitely a huge risk of putting something in the space of being 2 sizes at one time.
If you look at FTL as a linear speed then you probably have access to instant teleportation anyway, I feel as though acceleration and deceleration of anything traveling FTL would help alleviate a lot of confusion around space/time paradoxes. You would be looking at a lot more problems to solve with linear FTL such as matter being instantly obliterated as it instantaneously goes FTL. I like to imagine it as a function curve which starts out as STL then crosses the null line horizontally then decelerates to the same linear function of STL but below the null line. kind of like a tilda ~
I know all this is completely incorrect but hey might give someone something to think about or explain how wrong exactly i am :)
I agree. Instant FTL like teleporting would be kind of impossible. You could maybe transfer data from you to a copy of you in another location but this data would still have to be transfered from one point to another either at the speed of light or ftl somehow but never instantly. Not sure if i'm right tho
Every point in the universe has a unique energy signature. If you can create a device that could detect it and another device that could create it then you would be able to phase out of one location and phase into the location you want to be at regardless of distance.
But to transfer the data of your existence it must travel the distance. You could never make a perfect copy of you somewhere else without any travel through space and some amount of time
Bascailly, what I got from this is that as long as you don't have an STL ship traveling a significant percentage of the speed of light and using an FTL transmitter, then the odds of a paradox are bascially zero. And if we had FTL technology we probably wouldn't be using STL ships that travel at a significant percentage of the speed of light anyway. So it's a problem, but not a huge problem.
This video is an exceptional exploration of the possibility of faster-than-light (FTL) travel and messaging.
The research referenced in this video is outstanding, and the music and film/TV clips used make it more interesting. The video is well researched and presented in an engaging manner. If you're interested in space travel and its possibilities, this is a must-watch! Subscribe to their channel to stay updated with their research.
"The universe is not required to be in perfect harmony with human ambition." -Carl Sagan
Human ambition is not required to be in perfect harmony with an imperfect universe.
Humans aren't special
And rules are made to be broken.
This is BS because the line approaching the present could be curved like every line in nature.
Thank you for breaking my brain. I have always had a problem with relativity, but I am not an academic in such things, I'm a layman with little real understanding. This both helped me understand and broke my understanding...
I can’t do 73+29 in my head without panicking but these grand math problems fascinate me
Fascinating stuff. My brain feels like it wants to expand beyond the confines of my skull. I think once we understand the true nature of the universe we will better understand the possibilities and consequences of FTL.
there are no possibilities with FTL travel. FTL travel is impossible only something with zero mass can travel the speed of light. any spaceship you built to go that speed cant do it as the faster it travels the heavier it gets and then it needs more power. you would need infinate energy to get to the speed of light and that cant happen.
Correct me if I’m wrong but the paradoxes would only happen if your going FTL but if your going at 0.99 the speed of light you’d just experience what a person on plane sees to a greater extent in terms of time dilation
I love your conclusion.
Its true. I think the only real way to travel in space vast distances, would be in huge colony ships embarking everything it needs to last generations until it arrives on the next planet.
It would need so much abnegation. a loing term view big objectifs.
I like how Terry Pratchett said it better than the way Hawking did: Everything that happens, stays happened.
@JRod How would you know? What is, is. Upon that assumption rides all of science.
Thats actually because Hawkin is astonishingly overrated. A lot of people have described stuff he is credited with far more concisely, but his reputation, unique appearance, media buzz, and "pow science" makes everyone think he came up with things that are well known already. It disguests me that he is being credited with some kind of discovery of no causality violations, an axiom that essencially every physicist, and frankly anyone with common sense, has known for all time. Him phrasing it more "sciency" as if its some kind of profound statement is total bs.
TIME NEVER TRAVEL
Stephen hawking :there's no god (🤣)
which is why time travel is impossible. because it’d always be possible if it was.
Loved your video. Have your same feelings and hopes about it. But "Alcubierre" is a Spanish lastname. From one of our regions, the Basque Country. It's pronounced something like this "Al (like Al Copone), cu (like quality), bi (like bee), e (like elegance) and rre (like recognition). He is mexican with Spanish origins. Thank you and good luck ;)
This is the one video that finally makes me understand paradoxes
The easiest way through this scenario would be communication protocols like radio silence.
Thanks Dr Kipping
If space is expanding FTL, then we are also expanding at an FTL speed relative to everything else. Sort of like two jets traveling at 600 mph together that appear to be stationary to each other . If we were in a spaceship that somehow could halt our expansion speed, could we "travel" to another star that is in expanding space towards us?
Another possibility is whenever you travel or send message back in time, it's shift to a parallel universe. In this universe no sender in the future exists, they just receive a message/traveler from another universe. So no causuality is broken. This also goes in line with the multiverse interpretation of the quantum mechanics.
Yet again you combine scientific explanation with a thoughtful and beautiful message.
Thanks for one day deciding to start doing these videos, they mean a lot to me.
TIME NEVER TRAVEL
Hi ihhii
I hi hi
The key to this explanation of FTL travel and time paradoxes seems to be the idea that a person's space axis is always a reflection of it's time axis about the null line. That is why when the STL ship travels close to the null line that it's space axis is also moved close to the null line. It isn't clear to me from this video why that is. But perhaps that is a larger and more complicated discussion.
I have the same question, why is my space axis a reflection of my time axis across the null line, if an atom is at one point in space for a period of time, according to this idea the atom would also be instantaneously at another point in space
A fundamental problem with FTL is that voyagers could not return to their starting points without breaking causality.
I think the thing is that people assosiate time with the speed of light. Seeing something has nothing to do with when it actually happens. Time still exists even if you are blind
i'm wondering how photons are experiencing space and time, since they are travelling at the speed of light there fore there space and time axis are the same. the more impressive fact for me that i can see in this diagram is that if you moving away from the object you are literally travelling backwards in time for that object
I think there is a problem with the way the diagrams were drawn. The place it starts to break down (may actually be sooner but...) when the STL ship receives the message and then sends one back. It can most be seen when the message is sent instantly. The assumption is that the return message is actually received before the first message is sent. I have a problem with this. If there is a doorway where we can only view, not travel. You are on one end and I am on the other. You hold up a sign with a message. I see your message and I hold up my sign with my message. The two messages are sent instantly so the only time lag would be writing the return message. This means that the arrows that were drawn (specifically the second) are not drawn with the correct angle. Instead of the second being drawn further downward it should have been drawn upwards. I hope my description makes sense.
@Carlos Soriano I don't understand the angle of that message back to earth either. If you start with a message back to earth AT the speed of light, what would that angle be? Then go slightly faster... I do NOT think it would land you in "going backward in time" problems. I think the speed they chose is not only faster than light, it is an impossible speed that IS beyond reckoning. But if you back off that, I think the angle would be permissible. OR, if I am wrong somehow, then this would have been a better way of expressing the point: show how a lightspeed message is okay, and anything even a tiny bit faster than they is NOT ok.
@NotTheMaestro ok, and care to elaborate why is it so? Why it must be parallel to its space line?
@Jordan Sousa if you get a set square and put it on the space line, you’ll see the first message is going up, the second one which was instant is parallel hence it looks like it’s going down even more.
Remember this is from earth frame of reference.
It’s hard to wrap your head around it for sure.
@Carlos Soriano I wouldn’t say I’m the smart one. The reply from the ship has to be parallel with its own space line and the diagram is drawn from earth reference frame.
Omg this diagram finally explained why and how space and time are connected. Thank you so much. I always thought I understood this concept but I was just repeating info not fully grasping it.
Why do u draw Supernova X below the space line? Its not true
Why do u draw Supernova X below the space line? Its not true because u represent the whole 3D space with space line on this diagram
It hasn’t explained why the travelling object has a tilted line
Its always amazing howcsurprised humans are in their confusion over things they understand so poorly.
Honestly, the most depressing thing to think about is that if there is a form of FTL travel developed in the future, literally none of us will be alive to see it.
It's been too long since I learned how reflecting lines about different axis' works; how does the ftl comm reply at 18:10 result in that line, rather than its reflection about the time axis (since it's traveling the opposite direction in space, like described at 8:53), which would then not break causality since the comm will still be traveling higher up the time axis rather than back down?
This whole thing perplexes me too, but I found that his explanation at 19:10 was cool. The pink line going back to earth to say “don’t send the message” would have to travel parallel to the space axis of the STL ship, as the FTL message would travel instantaneously and can thus not travel through time in the perspective of the STL ship
Sounds like you have given up, I don't have the answer to FTL but I can tell you that we aren't looking at it from the lens we need too. Your null lines in the diagram sure did look a lot like an imaging scope for sound fields. It got me to ask how if it at it could be related, the answer I came up with is interesting if you'd like to reach out to me. Keep the quest alive friends!!
nah, you just don’t get it bro
i think the problem is reaching the speed of light itself, not going over, from my physics recollections, the problem is to reach the speed of light your ship reaches limitless mass, hence the need for limitless energy, but if by any chance we skip this threshold, maybe it becomes possible...
What is most beautiful about this video - is actually what it has done to the comments section. Look at all the wonder, the questions, the curiosity, the debate. All these wonderful human beings trying to discover - this is what I love most about humanity, we're all in this thing together :)
@Panse Pot no don't your brain will hurt badly
Have a look at the comments on some conspiracy videos. The moon landing deniers, or the flat earthers for instance.
absolutely mind blowing video. loved it
very well explained . thanks for sharing knowledge
Consider this. If we use the warp drive, the answer to this seeming paradox lies in the means used for faster than light travel. You see, the ship itself is not actually moving fast than light. Space is moving around the ship faster than light. It is shrinking the space between in order to move between Earth and Vega. If you correct your graph to account for the warping of space, I think that you will find that it puts the procession of events into the correct order.
I was thinking at something similar.
Not sure if I'm wrong, but maybe the "Vega receives warning" point was placed too far away from "Vega sees X".
What if the FTL message was sent from "Earth sees X" instantly towards Vega? It would arrive at the same point where the STL ship would arrive if it left earth before the message was sent.
The message is still sent faster than light, but not exaggeratedly fast like in the example given in the video.
In this way, it wouldn't break the logic of events if you slide the time slice parallel to the STL's ship's space axis AKA earthling perceived time.
If FTL is impossible, the upside is that the possibility of aliens attacking would be quite low.
Imagine being the first person to reach another star only to find humans have already colonized it because of time dilation
I’m in favor of the conclusion that if we encounter “paradoxes” in a scientific thought process we should consider that the concept is flawed. However, I would point out that the chart has problems when using the STL craft and it’s time slice. Even if one buys that the STL time slice is the correct angle here, it still matters where the craft is on that slice. The crew doesn’t get to instantly “know” when Vega sees things. You’d have to allow time for Vega to send the signal to the craft and by then the light from the super nova might have already reached the ship. In addition, the ship’s movement through space over the course of the events it does perceive would affect the value of this visual.
@Hammertime Here's a good question: where is the omniscient pov's time line? Maybe trying to have an objective perspective on a process that is quite literally relative is the problem here; trying to introduce a variable that is antithetical to the experiment. The explanation is flawed because it fails to address this; we have an objective point of reference: the light line. If that is the case, information cannot move against the vectors of the light lines, thus only up and across, regardless of your perspective.
TIME NEVER TRAVEL
juan abee Empirical evidence tells us that physical laws are consistent as far as we can see. We can sense and measure a lot about the observable universe. So what I'm saying is that the assumptions are not about the Physics. Dark Matter is point of discussion though, but its gravitational effects are known, and its source is being narrowed down and homed in on.
What’s the problem with seeing something before it happens? My drinking buddy Nostradamus has experience it before…
Thinking about this more. I'm pretty sure the result is due to the "instantaneous" message not being instantaneous in all reference frames. In this diagram it's instantaneous in the sender's reference frame, but not in the recipient's.
That might be the correct as far as special relativity goes. But then again, before special relativity everyone thought the speed of light was different in different reference frames and no one considered that it could be the same in all reference frames.
What does the result look like if we assume faster than light messages are the same speed in all reference frames, just like we assume with light? I don't think this would break causality. Though it might break other things. I need to think about it more.
Well.. sometimes there's circumstances that create two or more different speeds of sound. So I wonder if there's circumstances that could create different speeds of light? I'm postulating if you could cause variable light speed then you could also have variable time. But now wait a minute. Time is more related to gravity. I'm going to have to think about it some more.
Does anyone question whether or not if light actually has speed?
I have always been fascinated by this topic and this video is hands down the best explanation I've ever seen and breaks things down to the point that even I can understand the basic concepts of it and felt compelled to comment on youtube for the very first time ever, with some questions.
Earlier in the video, it was stated that "instantaneous travel was the most extreme FTL possible" with a pink line that went straight across the space axis. But later in the video, a FTL message from the STL ship sent back to Earth was assumed to be going back in time. This seems contradictory to me.
Why wouldn't the limit be instantaneous travel here also, going across the space axis back to Earth? Why wouldn't FTL still go forward in time (arrow pointing upwards), back to Earth, but just faster than STL?
From my limited understanding, assuming that the limit for a message to be sent to an STL (or FTL) ship is instantaneous, the message sent back would also be limited to instantaneous travel time. Why do we assume that we can go back in time in any of these scenarios?
I like to think that time is like a book. We each have our own unique book, everything is already written from start to finish, but we read one page at a time.
If you could go back some pages, (back in time) the simplest change would mean that the script has changed, therefore you would no longer be in the same book.
In this analogy, paradoxes are irrelevant.
I think as soon as something like FTL is achieved, we'll soon learn that there is some other, infinitely stranger arbitrary limitation way beyond our grasp that we could never have even conceived of before. I have dreams about it all the time, since I was a child in fact.
@Destan 6546 Are you affiliated with the secret space programs?
@Destan 6546 Science doesn't know what gravity is but you have it figured out. Ok.
This video perfectly answered all the question I had on the subject, thank you!
Logically, you could replace "light" with "sound" and "see" with "hear", and FTL with FTS etc. and by the exact same logic and graph, nothing can go faster than the speed of sound.
I'm not able to understand why the STL ship's space line (dotted red line) is at a lower angle than the ship's time (solid red line). Not saying you're , I may have missed something and would love to understand this model.
Edit: I see now why the model works like this, as it's explained that the space line is just a flipped time line over the 45° angle.
14:50 I really tried to understand and comprehend this, was fine all the way up to the dotted stl axis..and I struggled :( rewatched and still can't get it. 😔
Edit: I watched the rest and as Marty Mcfly once said, (almost) 'I guess I'm just not ready for this stuff yet' 😅
A fascinating and intriguing topic, however.
The diagram is wrong it is missing some variables.
Time is relative for each object even the message itself, at 14:50 it doesn't say amount of time for the ship to receive the data OF VEGA.
So even if Vega at that moment sent message FTL, the ship would still receive it in it's relative time.
Example is, the message of Vega to the ship itself would have 'sense' of 1 second traveling, BUT when it reaches the ship, the time passed for the crewmembers would be a lot more.
@FantaWriter I actually really like the Brian Green example, using a loaf of bread where time is described in a series of infinite moments each one a slice of bread, bread being the space. I understood the relativistic logic there.
I don't think this diagram is even accurate, since the order of events from the "crews" perspective shows that Vega Receives Warning before they even leave Earth, but they would have the same time slice as Earth until then.
It was all very nice explained and I understood almost all of it. there is only one thing I am trying to figure out.
in the Diagram, why is the Space axis for the STL ship at an acute angle? wouldn't that mean that, even though they are traveling STL for us, it seems for them as though they are traveling faster than light? because, for them they are closer to the space axis than the time axis.
I hope my question is understandable.
I always love the very grounding and philosophical thoughts proposed in these videos along with the theory. Really helps to place the science and the importance of these studies in a broader sense and why or why not humanity should pursue them.
Well said.
Our understanding of the physics of our universe is rudimentary, at best. People once truly believed that it was impossible to break the sound barrier.
How small of a an object or particle would it take to damage an object going the speed of light
If our efforts at FTL create paradoxes, what happens since parts space/time are currently traveling several times faster than light relative to us?
@Astro Good answer! Thanks for your detailed reply!
Since spacetime is moving FTL relative to us, we are also moving FTL relative to those same parts of spacetime. The reason it doesn’t create paradoxes is because the speed limit of light only applies to things that move THROUGH space, it doesn’t apply to space itself.
So when we look at a distant galaxy moving at a speed that seems to be FTL, the galaxy isn’t actually moving, or at least it’s moving much slower than it appears. One way to envision this is to think of 2 ants on a balloon. An Ant might only be able to walk 1 inch a second, but if you blow up the balloon as they walk apart, they could end up 10inches apart after 2 seconds because the surface of the balloon is expanding so fast, even though they are only walking 1in/s.
Before we move anything at the speed of light, we need to figure out how we would transport people at such speeds. The human body would be obliterated if we tried. I think that’s an even more difficult if not impossible task than actually reaching the speed of light.
Something people are struggling with is why the line is moving downward in the STL Ship example with the FTL transmission. It's understandable, given how unintuitive physics is with common sense. Im not 100% sure either whats exactly going on, but I think I can grasp enough to put it in laymans terms.
So when the STL ship is moving through space, time around it is dialating according to how fast you move through space. The closer to the speed of light you are, the faster time seems to move around you as space literally speeds by. The problems begin when you reach the speed of light. What happens?
Firstly, you are now past the speed of light. Think of a car. You know how when a car drives by you at the same speed, it almost looks like it's not moving at all, even if you know it is? That's what would happen to time and space around you as you perceive it. To light itself. Now consider what happens when you begin to outspeed light.
It would move. But not forwards ahead of you. But behind you. Space and time would be so slow by your perspective that it would begin to move backwards, literally. The closer you get to another object, the further back in time that space will go. Atleast, in theory.
There's definitely alot more to this, but don't feel bad if you can't figure it out. This is literally the science people spend their entire lives attempting to solve. Understanding the fundamental underworkings of our literal existence isnt something you just happen to have the ability to do. You are flesh and blood, and your instincts as well as common sense do not apply to the chaotic, esoteric universe that lets us live in it.
In short, FTL might be fundamentally impossible because of physics, the theory of relativity, and paradoxs. To break a hardset rule might just not be physically possible, and we wont know for certain UNTIL we can figure out why Quantum Mechanics and Relativity don't mesh perfectly. Hope this helps, any physicists feel free to come and tell me if Im wrong somewhere. My understanding is very limited, so my word isnt law here.
Outstanding! FTL was always a dream since watching Star Trek as a kid. The fact that we can glimpse these wonders of the universe as water filled meat sacks is truly amazing. Even if it isn’t possible, I appreciate that logic as to why is isn’t possible. Space is big. We’re living in an age of high definition discovery.
Wouldn't call humans just water filled meat sacks. We are an outstanding species that just appeared shortly on earth. Our intelligence and consciousness is a God's given gift truly. In the future I believe we'll be able to change universe to our fit
Water filled meat sacks, lol 😂
The idea of the multiverse fixes this. The paradox is simply avoided by the ship's reply back to earth creating a new reality. Now there's 2 earths were one never turns off the FTL machine and one where it does
If the idea is to work together for something beyond that is attainable by our own mortal timeline, for the benefit of the next generation or of the survival of humanity, then the ants and the bees have already beaten us to it. The movie Interstellar has given us this message in its final scenes.
@The Great Hadoken Your negation is on a frame that is Material and physical. My comment was actually framed in the philosophical, spiritual and cultural context. Of course you can easily squash those bugs, why then did I say they are better? well, there's the difference in the framing of the context.
What I am highlighting is their superiority in organization, perhaps maybe their structured governance, class function and collective utilitarianism. But then of course the hive-mind, swarm and collective principles are required which are not attributes prescribed by nature to humans and even other advanced species. Communists tried to emulate the principles to a certain degree, but never effectively and consistently like the insects do.
Maybe it only works for smaller organisms that can produce their own materials and not need more than what they personally utilize. As compared to capitalizing on fellow smaller organisms for enterprise and bucketloads of camel dung currency or trade resource. I cant say for certain, but maybe. just maybe, we wont be able to break the next barrier of civilization development unless we adopt a culture similar to those bugs.
All of those goodness and yes, of course, you can easily squash them and burn them and they only get to space if you put them in your pockets or your drawers.. they don't have their own rockets, their weapons are even their own teeth! Imagine going to war with UK, and the geneva convention prohibits use of any other weapons of war but your bare unjacketed, unbrushed Teeth! UK would lose i know but that was the joke. lol These bugs even have to live close to human homes to conveniently find food and water. I hope you see the miss now. :D
In short, between my comment and your counter, there really was no intercept. Like I aimed for Andromeda through the dark side of the moon, but from the same moon on the brighter side, your aim was back to the earth. No linear intercept in idea, vector, frame and context, whatsoever.
Nevertheless, I agree with all your physical assessments of how the world is naturally existing at this very moment in time. ;)
Seriously though, thank you for sharing your thoughts. I appreciate people who think.. unlike most of the modern people today.
Perhaps every instance of paradox creates its own tumeline and universe.
According to the graph, instant communication would be possible between two points with the same space axis. This would make it impossible for the moving ship to send an FTL message to either planet. It would be impractical since the planets would have to be perfectly stationary relative to each other, and gravity could screw that up easily, but it's theoretically possible according to this video.
Interstellar is a great movie and it actually got me wanting to go to space, im 15 so i have my whole life ahead of me and i can't wait to see if i am actually able to accomplish my dream
Best explanation of time travel paradoxes I've seen in a long time, thank you for this! I feel so amazed that on one hand we can theorize and explain stuff like this yet a lot of people will still doubt that we ever went to the moon.
@Kayla Leave They left laser reflectors on moon to calculate exact distance from it. When you throw lasers on the reflectors at a perfect angle, the laser will bounce off from the reflectors on the moon and reach Earth.
This can also be served as a proof that if laser is bouncing back at a perfect angle from moon to Earth, then surely someone went to moon and left a mirror at a perfect angle. And I'm pretty sure it was us humans who did that.
Because he uses theory of relativity which relates to light in time and space and attempts the correlates to different objects in time and space then takes a hypothesis vessel in time and space. Then attempt come up some silly idea that the FLT vessel is able to go another plant drop for a message has some how caused some break in cause and effect has been shown at all. All he did was show a hypothesis and bad one that. We don't have FTL we have no idea the relationships between traveling to such objects. We don't even understand time and space yet. Einstein pointed out that space isn't nothing but something and keep thing it is nothing. It bend it warps it does stuff we can even wrap our heads around yet and his guy is make bold statement like this. What is time? It is tied to space but how? We haven't tried to find that answer. If you say time travel paradoxes then your also saying a space travel paradoxes because they are just like electromagnetism you can't not part one from the other. Have you thought that maybe as you past the speed of light time goes backward because it stops when you hit light speed? He never speaks of this fact. So basically those people traveling at light speed do get there in a split second or did you for get relativity also apples to how one see time pass.
That's a time paradox.
We never went to the moon. They never went to the moon in 1969
If we're "trapped" by the speed of light, I would imagine that it's for our own good.
I don't see how causality is broken here, because the STL ship isn't actually affected by Vega receiving a warning. Even if Vega were to message the ship at the same speed as their incoming message, the ship would be notified of said information (say plans to evacuate or whatever) around the time of the supernova. They would be unable to effect changes to the outcome. The only ones capable of changing the outcome would potentially be Vega - this is the thing that seems causality breaking to me. What if they could prevent the supernova? Then they would never have been warned, right?
If we couldn't sense light we would think that going faster than the speed of sound might cause paradoxes.
I have traveled through a deep dark hole many many times and seem to find myself amazed everytime
you are great and i love your videos keep up your good work
I like how he predicted every point where I got confused or skeptical and delivered a good answer without me ever asking anything lol
About the talk in the end about exploration without FTL, it was quite poetic, but individuals can actually experience it one day and travel to many stars, considering there is no barrier in the laws of physics that say living things can't last for billions of years. More than that, the way in which time is perceived can be drastically modified, where a million years travel can feel like a mere hour. Just imagining human-like consciousness in a digital substrate is enough to see how this things are possible
TIME NEVER TRAVEL
@Mia yeah in theory maybe. but in reality you would need infinite speed or infinite gravity to get infinite time dilation afaik. also if you want to park hubs "outside of time" you would basically have to park them almost inside the black hole which would be almost impossible and starting from it would take a fuckton of fuel because you have to overcome the gravity.
Time dilation can approach infinity. Through time dilation it is theoretically possible to make a billion-year trip feel like a year. I imagine we would have hubs "outside of time" parked at black holes. Ignoring the radiation problem for now haha. The hubs would keep humanity somewhat cohesive, but travel outside the hubs would be one-way trips. I imagine we could use the black holes to accelerate ships to insane speed. Theoretically, occupants can travel across the galaxy within a human lifespan. They could keep the hubs informed, but communication from the hubs would be impractical. We wouldn't be able to overcome the expansion of the universe with this method though.
This is more of a story idea, but I think it's physically possible. There isn't much to gain commercially either so this happening, in reality, is slim without a change in our culture.
Repent to Jesus Christ
“He is not here; he has risen, just as he said. Come and see the place where he lay.”
Matthew 28:6 NIV
C
@Georgi Rusev *Absolutely illogical what you claim* ! Absolutely ...
As soon as you start slowing down, almost all your benefits are lost ...
By the way ...
*You can never* reach the "edge" of the Universe! Never!
(At most, if you turn it to self ...) As for, it's also nonsense ...
It seems to me like the "protagonist" of causality is the one with agency. It would seem more intuitive, if the realities that the STL ship intercepts FTL message and sends a reply, and that Earth receives the reply before sending the message exist simultaneously. Of course, this could have some kind of crisis "prophecy" applications, wherein you just have to assume that unsolicited messages have a context that exists from the STL ship's perspective, but are absent in your own. It might be a good way to undo or mitigate cosmic catastrophes, to surround your solar system with detection satellites equipped with FTL relays.
You would just be in your office and you would receive a message saying "Don't tell anyone about the supernova about to happen." They would later land and rendezvous and report that you had previously send a message stating that a supernova happened, do they sent one back in time to tell you not to bother. In a way the STL ship would be its own pocket of causality, unrelated to the wider universe. To suppose this somehow breaks the universe would suppose any form of clairvoyance also does so. I'm aware the latter is fantasy, but that's also what's said of sufficiently advanced technology.
Man great word choice in the introduction, you play beautifully with words and caught my attention with this awesome introduction so much that i just had to write it in a comment, you have a new subscriber:)
So since most of this is theory and assumptions I will question how this STL ship is capable of picking up non direct signals and messages at the speed of light (I imagine that FTL messaging would be more of a P2P affair than standard signals). Because while yes *technically* effect happens after cause but only if they receive this information at or faster than the speed of light. Which means that from the perspective of the crew, yes its a paradox, but its the same as if I got an email telling me about an oil spill and then got a newspaper that told me about how an oil tanker lost control and may or may not miss an island. In theory I could perceive this as a paradox if I chose to believe the newspaper to be more up to date than the email.
So if Vega can get a warning can get a warning THEN later will see it, that means theoretically as soon as you get the warning you can travel at FTL to prevent it from happening thus going back in time
imagine you are somewhere else in the universe. now imagine you wanted to travel here. there you go. just saved a hell of a lot of time energy and effort.
What a wonderful episode. I really loved the prespective you provided at the end. To view this inate limitation of sub-FTL speeds as a blessing, because it might compel us to live for future generations beyond ourselves. Beautiful stuff ^_^
If we did travel at the speed of light, what's stopping us from instantly running into a field of meteors or a rogue planet at that speed?
So if alcubierre was inspired by Star Trek does that mean the writers of Star Trek accidentally invented a fake explanation for how to do FTL that just happened to actually be legit or did they get consultation from physicist who told them to word warp drive like that
If speed equals distance over time, speeds anywhere near c will literally be FTL. Another funky flaw in FTL is that once at c it should take zero energy or food stocks or oxygen to maintain their travels since time stands still🤯