Is Faster-Than-Light Travel or Communication Possible? (1997)
math.ucr.edu
math.ucr.edu
A little math shows the relative velocity in which you travel one light year measured in a rest frame, in one year in your spaceship's frame, is 70.7% of the speed of light.
If you happened to be moving at the ludicrous speed of the "Oh-My-God" cosmic ray recorded in 1991, it would take you three seconds of your time to travel to the center of the galaxy.
That should be good enough for anyone!
It might feel more like time travel than space travel.
There was also an point in that episode since the FTL method they used was tethered to massive objects and hence only allowed for travel from on star system to another (or from one galaxy to another) the old fashioned non FTL method allowed them to explore many more things than with FTL travel the downside that 10,000's years would pass for everyone else every time they take a trip.
Poorer people leaving later get better and faster transit.
The only advantage of leaving early is the guarantee of getting a transit, instead of waiting for a better one to arrive later and find you got nothing at all.
After about 10 thousand years of hearing the beacon and being alone we finally get restless and just build a couple thousand giant spaceships and join the rest of the universe in the most cosmopolitan place ever.
Do we need a theory on this yet? I mean... out of all the planets we've explored reasonably thoroughly so far, 100% have had life at some point.
Intelligence might not even bet he end goal of evolution even life is very common, intelligence might not be.
Douglas Adams' books have been a major fixture of my life since I was 12. He really was ahead of his time. Actually I don't think said time he was metaphorically ahead of has come yet :)
Indeed, the fourth draft of the script has this comment after the "twelve parsecs" line: "Ben reacts to Solo's stupid attempt to impress them with obvious misinformation." The final draft says he's "obviously lying."
I feel like this ridiculous retcon involving black holes, rather than sticking to the simple human explanation of braggadocio, is a microcosm of everything that subsequently went wrong with the prequels.
It states rigorously what it means to be an object ("observer"), and what it means to travel faster than light, and proves that observers cannot travel FTL. In special relativity, though, not GR yet.
You can't do it, there are no hacks to do it. It's a law of the universe. No matter how many SciFi movies tell you other wise.
I just don't get the acceptance of this anti-scientific concept.
Perpetual motion and FTL travel are about physical laws, which are not known in full. We've got some really good theories with a lot of data to back them up, but the facts lie in the data, not the theories. The theories are subject to refinement and replacement as better data is obtained.
It is not known that perpetual motion or FTL are impossible. It is believed that they are impossible, because the best theories to explain current data say they are impossible. But there is room for new data and new theories.
It was not all that long ago that it was "scientific fact" that atoms were indivisible (that's what the word means, even), that velocities add linearly, that light propagates through a fixed medium, that matter is conserved, and that gravitational force is proportional to mass and inversely proportional to the square of distance.
I also don't see much "acceptance" of FTL as physical fact. I see it accepted a lot as a story device, but that's just because it's handy for making entertaining stories, not because there's any basis in physical fact. There's some "acceptance" of FTL as physical fact in that people don't completely rule it out, but that's entirely justified.
c is a bit more established than "scientific fact" like the behavior of atoms were once thought to be, it is very mathematical, as is the curvature of the earth being > 0. In principle new data could come in showing these things to be false, in the same sort of way twice 2 may not be 4.
Another similar fact almost beyond experimental disproval is https://en.m.wikipedia.org/wiki/Identical_particles
I do very much doubt FTL, not only for the physics reasons but for other circumstantial ones. If FTL is possible then the Fermi paradox goes from being an intellectual curiosity to a near metaphysical emergency. If there is FTL then either we are absolutely alone or there are aliens everywhere and they are hiding from us or for some reason we can't see them. That's because the first expansionary intelligence to discover FTL will fill at least the galaxy if not the entire universe in a geological eye-blink. Since ubiquitous aliens hiding seems less likely, if a pathway to FTL were discovered I would immediately conclude that we are alone in the galaxy at least and possibly beyond.
Even at a fraction of the speed of light, the amount of time to expand and fill the galaxy is still an eye-blink in geologic time. Even in evolutionary timescales it's still an eye-blink -- the Cretaceous era ended about 66 million years ago.
I think the depressing truth is that we are alone in this galaxy. See [1] for Michael H. Hart's extremely compelling discussion of this idea.
Maybe. Maybe not. This is how UFO conspiracy theorists reason - "Here are some phenomena I don't understand, I can't think of any plausible explanation for them, therefore, must be aliens".
There may be some hidden reasons why we can't detect FTL civilizations.
There are numerous rational reasons that an intelligence exploring the universe might choose to be very very careful about initiating communication to the point of taking steps to avoid even accidentally revealing itself. Some of these are altruistic (e.g. prime directive and contamination concerns) and some are self-interested (see game theory, and consider the apocalyptic destructiveness of conflict between really advanced intelligences).
I wouldn't go quite so far as to say it's totally impossible though. There is a whole lot about the universe we don't understand and I can't rule out the possibility that there are entire branches of mathematics and physics that we don't know about.
Imagine a friend and you, moving very fast with respect to each other. You measure your friend's clock as advancing slowly (due to time dilation), on account of the fact that he's moving with respect to you. But your friend measures _your_ clock as advancing more slowly than _his_, because motion is relative.
The way to reconcile this mathematically is to give up on absolute simultaneity of distant events. In other words, when two things happen in different places, at the same time according to your clock, they happened at different times according to your friend's clock. This is analogous to how you measure your friend to be in different places in different times (because he's moving with respect to you), but he measures himself to be stationary, always in the same place. To recap: If comparing things at different moments, "being in the same position or not" is relative to the observer. If comparing things at different places, "happening at the same time or not" is relative to the observer.
That's how causality comes in. If your friend tosses a very fast ball at you, and the moment you receive the ball you start towards him faster-than-c, you'll arrive where he is before he tossed it (if you went fast enough). That's what the equations say. Now the breaking of absolute simultaneity allows naturally for disagreements on what of two things happened first, assuming they happened far enough from each other that light couldn't cover the distance in time. But by putting faster-than-c velocities in the equations, we have your friend and you disagreeing on what happened first (him tossing the ball, or you arriving where he is?) in what (to him) is the same place. And it's not just a confusion of the mind: all your measuring and recording artifacts will agree with you, and all of his will agree with him. The mathematical conclusion is that if you can send information faster-than-c, you can send it back in time and break causality.
I understand it this way. Assume I were traveling away from my friend at twice the speed of light. My time of departure is 12:00:00. After 1 second (my clock) I have traveled 2 light-seconds. Light reflected off the face of my clock now travels towards my friend, reading 12:00:01. We'll call this view of my clock a "snapshot."
From my friend's point of view, that snapshot reaches him at 12:00:03. Yes?
Now, we allow for 1 additional second, my time. I have traveled in total 4 light-seconds. My 12:00:02 snapshot now travels towards my friend. It reaches him at 12:00:06, his time. Yes?
So, from my friend's point of view, my time has seemed to slow down. Is that what you mean by time dilation?
When you come back, he'll be much more "aged" than you. You had a clock on-board your craft, and it measured your trip as say "2 years". Likewise, your twin also had a clock and it measured your trip as having lasted "20 years". The clocks are not wrong. And trust me, this isn't some science-fiction type thing we're discussing. GPS satellites orbiting the Earth carry very accurate atomic-clocks, and they need to take time-dilation into account in order to compensate for the drift in values, simply due to the accuracy necessary for GPS. Just had a look on the wiki page, and the drift is approximately 38 microseconds per day.
When I first encountered this concept in high-school randomly, I was quite shocked at how "non-complicated" the equation for it is.
https://en.wikipedia.org/wiki/Time_dilation#Simple_inference...
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P.S. Never mind. I follow the diagram now. I'm trying to follow the rest of it.
Imagine the same scenario you described (there's actually no need to use faster-than-c speeds for it), but your friend has planted clocks all along the path that you're traveling. Once he's back at his starting position, he synchronizes them all (there are techniques to achieve this - Einstein famously proposed one). Now when you pass him and keep moving away from him, every second you take a picture of your own clock next to the clock planted on the path. In a non-relativistic world, the pictures will show that your clock is always synchronized with all of your friend's clocks. Making the observation this way rids us of the Doppler effect.
But a non-relativistic world isn't the real world! In reality, if you go fast enough (close enough to c), the pictures will show e.g. your clock marking 12:00:01 when the clock in the path marks 12:00:02. And your clock marking 12:00:02 when you encountered the next clock in the path marking 12:00:04. In other words, your friend (and everything that's stationary with respect to him) will measure your time passing more slowly. Using these example numbers, in what for them is the pass of 2 seconds, you (and everything moving at your same speed - like your clock) have only aged 1 second. This is relativistic time dilation. It's shocking, but it's a fact that's been established for 110 years (and its mathematical consequences help explain even the microelectronics you and me are using). Now this happens no matter what speed you move with respect to your friend. But for everyday speeds it's so small as to be imperceptible - it only becomes noticeable at speeds like that of GPS satellites.
An immediate question is:
> Wait, if I move away from my friend, from my point of view my friend is moving away from me. So I should measure his clocks advancing more slowly than mine.
And that is correct, and is exactly what would happen!
> But the pictures I took show the opposite?
No! They show your clock compared to different clocks. And these clocks on the path, that your friend synchronized, by your measurements they all started at different times. I.e. for you, none of these clocks are synchronized. For your friend, they all marked 12:00:00 simultaneously. For you, they all marked 12:00:00 at different moments. In non-relativistic physics, simultaneity was an absolute concept: If two things happened at the same time, they happened at the same time for everybody. In reality, if I'm moving with respect to you, what happens at the same time in different locations for me, doesn't happen at the same time for you.
The speed of light isn't an intrinsic property of light, it just so happens that light travels that fast and it was the first thing we were able to measure that was traveling at the limit.
If you were traveling at FTL velocities, you would effectively get there before you left.
To be more exact, aren't you saying that you would seem to get there before you left, from the point of view of someone not traveling with you who is observing you from some particular vantage point?
Granted I believe that doing so would probably involve bending space/time so that your actual position was in the new frame.
Other reasons.
Fundamental principles of the universe also say heavier than air machines should be impossible.
FTL issue is the same thing. Its possible, it just won't happen in the way we might expect.
My point being that, yes, these two are comparable, which is what the claim you are replying to said.
In fact, belief in FTL is sillier that violation of conservation of energy. We have no evidence for FTL of any kind. We do have some reason to believe that conservation of energy is in fact violated at cosmological scales by the increasing rate of expansion of the universe. (Perhaps future understandings will resolve this apparent violation with a more complete picture of "energy", but at the moment, what we know of as energy is not being conserved at that scale.)
There are rules that you can see and access, and those you cannot. Both are in some sense irrelevant to your own perception of truth because they are determined outside the bounds of your empirical experience.
What good evidence do you have to refute such an explanation [surely its likelihood increases in line with our own ability to create the 'next turtle down'].
We have to learn how to do it and then we will do it.
You have atoms and quants and whatnot. Now you add one and one another. You keep adding and soon or matter there is a slip. Basically you get the universe to a buffer overflow. All still following the laws of physics. Like you get a cpu limited of his numbers you get the universe to a buffer overflow.
Now one could say, but the universe is endless. Which means you would need endless energy for that buffer overflow.
But who says you need to create that buffer overflow in the whole universe and not in a cube? And who says the universe is endless?
Not that it changes much...
Another article that raises the same question is http://www.bbc.com/future/story/20150318-will-we-ever-speak-...
Now one aspect I'll add is that it may be possible but would the integrity of the information communicated be maintained and with that it would still be a case of no.
For me a related theory is that black holes convert mass into energy and that energy dissociates with current space and time and some of that ends up at physical location in space of 0,0,0 and time 0 as that is the earliest point in time and space. That and with all black holes over time venting so to speak to that point in space in time, was the reason for the big bang. Again a theory of mine. Now in that case something from now has gone back in time and yet has it gone faster than light? Or indeed is there anything sent that is recognisable from when it entered and in that case - no. So again whilst FTL communication may be possible, the whole aspect of integrity of that communication is a whole other aspect.
Equally the speed of light, there is another theory that the speed of light has varied over time (VLS Variable light speed) and whilst some observations lend themselves to this, it is still a theory. So that is another aspect in this that needs to be factored in. In short light may of been faster in the past, or it may of been slower and that add's a whole new layer of complexity upon this issue.
Science is fun isn't it, be darn boring when we as a species learn it all, but not in any of our lifetimes and that for me is a good thing. Though like many theories and great scientists there are and still are people who just dismiss without debate and with that how many people in the past burned or killed for saying the earth is not flat. Still be interesting for constructive perspectives and debate upon this, but alas as a subject many just dismiss and blindly label. Which is sad, in any time, even today :(.
You might be thinking of the heliocentricism mess; but Bruno was burned for beliefs that had nothing to do with heliocentricism, and Galileo was only confined to house arrest -- and that after the Pope had tried to compromise with him, and Galileo responded by putting the Pope's arguments into the mouth of a simpleton in a revised version of the _Dialogue Concerning Two World-Systems_.
This is a tangent to your main argument, but it's an important thing to get right; you can't reach truth if you start from misconceptions...
Yip your right, my mistake, good to learn. Least none can name and was indeed thinking of Bruno at the time, my bad.
Thank you for the correction and sorry for the misconception correction by me.
I thought you might be thinking of Bruno, the scientist who really was burned at the stake; it's a good thing for everyone that this wasn't for his science. (Of course, it would've been better if people weren't burned at the stake in general. Certain modern elements have reminded us of how painful a death that was...)
I also learned a few things about Galileo from Biography Base's article on him; thanks for that link!
The more I learn about that case, the less it sounds like Religion versus Science and the more it sounds like a conventional miscarriage of justice. A frail, sick, stubborn old man should never have been treated like that, even though he did call the Pope a simpleton. The Pope is the Pope, and has certain standards to maintain; it doesn't reflect well on Christ when His Vicar abuses the courts to make trouble for people who insult him.
The only problem is having synchronization of time over distance and hoping the dE.dt does not require exponential energy growth over intended distance of communication and that the energy per bit is not too expensive.
But yes this article was indeed done in 1998 where USA university may have discarded science from under developed countries such as France.