121–130 of 168 posts
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> Warp drives change the geometry of causality. Those are all words, and that's about all there is to say about your comment.
Why are you sharing your opinions about a mechanism when you don't even have a remote understanding of the basics?
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Warp drives do not violate the speed of causality; they change the geometry of causality.
From wikipedia ---- In both Einstein's theory of special and general relativity, causality means that an effect cannot occur from a cause that is not in the back (past) light cone of that event. Similarly, a cause cannot have an effect outside its front (future) light cone. ---- end wiki I guess FTL would violate that definition of casuality, but I assume if discovered, we'd just change the definition of casuality an…
cause must precede effect _for all observers_. Relativity is involved now, and these observers will not agree on how much time has passed, or even if 2 events were simultaneous or not.
FTL travel of matter or information inevitably gives rise to frames of reference where this 'cause must preceded effect' is not so.
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Here's the problem: Event A at location X at time T1 causes event B at location Y at time T2 > T1. If I can travel FTL, I can find a frame of reference where T2 before the cause. This leaves a few possibilities, and they're all bad: - There is no real cause and effect. - Cause and effect are real, but effects can come before causes. - The laws of physics are not the same in all frames of reference. Our current unders…
> If I can travel FTL, I can find a frame of reference where T2 How? Sure, it's possible that the light from an event happening at T2 arrives before the light from an event happening at T1, but that says nothing about when those events actually happened - just like how if we hear one lightning strike before another, that doesn't mean the one we heard first actually happened first. That is: this notion that all superl…
> this notion that all superluminal travel somehow magically necessitates the possibility of backwards time travel doesn't seem to be logically sound.
There is literally decades worth of physics that answers your how, and explains the soundness of it, I would urge you to study the subject in well, any depth at all before naively dismissing it as "unsound". I mean, who's more likely wrong: Physics since Einstein's 1905 papers, or guy on the internet who's been thinking about it for 10 minutes, and has questions with basic misconceptions in them.
Asking for answers in the comments is a very poor way to approach a subject like this. All you'll get are quick responses and displays of ignorance.
I'm surprised that so far nobody here has complained that they got the Star Trek trivia wrong! I don't remember the details but there's plenty of exotic matter and energy involved in the handwaving that's supposed to explain how warp bubbles form in Star Trek.
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> If I can travel FTL, I can find a frame of reference where T2 How? Sure, it's possible that the light from an event happening at T2 arrives before the light from an event happening at T1, but that says nothing about when those events actually happened - just like how if we hear one lightning strike before another, that doesn't mean the one we heard first actually happened first. That is: this notion that all superl…
> How? > this notion that all superluminal travel somehow magically necessitates the possibility of backwards time travel doesn't seem to be logically sound. There is literally decades worth of physics that answers your how, and explains the soundness of it, I would urge you to study the subject in well, any depth at all before naively dismissing it as "unsound". I mean, who's more likely wrong: Physics since Einstei…
And as I've already stated, none of it has been even remotely adequate. If it was, then I wouldn't be asking stupid questions with "basic misconceptions" in them. Maybe I'm too stupid to understand it.
> or guy on the internet who's been thinking about it for 10 minutes, and has questions with basic misconceptions in them.
Care to actually articulate those misconceptions?
Like, I'm under no illusion that I'm correct here. I'm literally a community college dropout. I'm only attempting to find answers to questions I've been asking for years and for which I've yet to find an answer.
Instead of an answer, it seems like today I'll be getting downvotes and ad hominem dismissals. Oh well.
> Asking for answers in the comments is a very poor way to approach a subject like this.
It's called having a discussion, which is quite literally the point of this website. If you don't want to engage in that discussion, then nobody is forcing you to.
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From wikipedia ---- In both Einstein's theory of special and general relativity, causality means that an effect cannot occur from a cause that is not in the back (past) light cone of that event. Similarly, a cause cannot have an effect outside its front (future) light cone. ---- end wiki I guess FTL would violate that definition of casuality, but I assume if discovered, we'd just change the definition of casuality an…
> 'cause must preceded effect' cause must precede effect _for all observers_. Relativity is involved now, and these observers will not agree on how much time has passed, or even if 2 events were simultaneous or not. FTL travel of matter or information inevitably gives rise to frames of reference where this 'cause must preceded effect' is not so.
Why would FTL automatically invert causality? Assuming we chuck out, the speed of light limit, like I originally said in my previous comment, which if FTL was possible, would end up being the case. Has the expansion of space ( present day -or- the inflation event, both involving FTL which is allowed under relativity ) already inverted causality?
Mostly I was just trying to point out that it appeared commenters were arguing from two different point of views, one with the intuitive cause and effect definition, and the one from relativity which makes certain assumptions about the universe ( well tested assumptions, but still assumptions, that could be proven false one day ).
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> How? > this notion that all superluminal travel somehow magically necessitates the possibility of backwards time travel doesn't seem to be logically sound. There is literally decades worth of physics that answers your how, and explains the soundness of it, I would urge you to study the subject in well, any depth at all before naively dismissing it as "unsound". I mean, who's more likely wrong: Physics since Einstei…
> There is literally decades worth of physics that answers your how And as I've already stated, none of it has been even remotely adequate. If it was, then I wouldn't be asking stupid questions with "basic misconceptions" in them. Maybe I'm too stupid to understand it. > or guy on the internet who's been thinking about it for 10 minutes, and has questions with basic misconceptions in them. Care to actually articulate…
> because the only way to go back in time is to have a speed greater than infinity
> Instead of an answer, it seems like today I'll be getting downvotes and ad hominem dismissals. Oh well.
Probably because your approach is very confrontational for someone who claims to be "just asking questions" e.g. "unsound", "not remotely adequate". And then you're dismissive - get directed to a wikipedia page where it's answered, and the mechanics of it are done in mathematics, and: "That doesn't answer the question. ... by what mechanisms?"
OK, maybe that approach isn't for you you. Pop science books are a thing, try those instead?
I'll add one thing: I'm a software engineer, but if you gave me 1000 lines of Rust to read, all I could say is "I have a very superficial reading of this code based of function and struct names, because I don't really know Rust at all."
There's nothing wrong with that: specialised topic is specialised. It's ok to admit you don't know the details. What I would not say is "this program is not an answer, because I don't understand it." That would just be an egocentric misconception.
> nobody is forcing you to
You're right, if someone is being obnoxious and pointlessly confrontational, they won't get the best from the people who interact with them. No-one is forcing them to do it! But combining that with "oh why am I getting downvoted and dismissed" wailing seems disingenuous though.
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> 'cause must preceded effect' cause must precede effect _for all observers_. Relativity is involved now, and these observers will not agree on how much time has passed, or even if 2 events were simultaneous or not. FTL travel of matter or information inevitably gives rise to frames of reference where this 'cause must preceded effect' is not so.
Yeap, with the speed of information having a propagation limit, you can make that assertion. But, as soon as FTL becomes real ( if it's possible to be real ), it turns out, that assertion was wrong. The universe has no requirement to follow our theoretical framework. Why would FTL automatically invert causality? Assuming we chuck out, the speed of light limit, like I originally said in my previous comment, which if F…
And yet it does, that is just the mathematics of it. Another commenter linked this worked example: https://en.m.wikipedia.org/wiki/Tachyonic_antitelephone
> well tested assumptions, but still assumptions, that could be proven false one day
But not in the way that you seem to be implying. They may be proven _incomplete_, but existing measurements confirm that these assumptions are mostly correct (to high degree of accuracy, and over a lot of measurements), and so won't be superseded by something completely different that contradicts those measurements.
The best essay on this subject is "The Relativity of Wrong", Asimov, 1989
https://chem.tufts.edu/answersinscience/relativityofwrong.ht...
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> There is literally decades worth of physics that answers your how And as I've already stated, none of it has been even remotely adequate. If it was, then I wouldn't be asking stupid questions with "basic misconceptions" in them. Maybe I'm too stupid to understand it. > or guy on the internet who's been thinking about it for 10 minutes, and has questions with basic misconceptions in them. Care to actually articulate…
Misconception: > because the only way to go back in time is to have a speed greater than infinity > Instead of an answer, it seems like today I'll be getting downvotes and ad hominem dismissals. Oh well. Probably because your approach is very confrontational for someone who claims to be "just asking questions" e.g. "unsound", "not remotely adequate". And then you're dismissive - get directed to a wikipedia page where…
And how is that a misconception? That seems to be exactly the thing the "answers" describe: the time it takes to travel from point A to point B being negative, somehow. Even when discussing problems where we've defined that duration to be positive.
> Probably because your approach is very confrontational
Just because you perceive it to be so doesn't mean it is. Just like, relevantly, how two signals arriving at a reference frame doesn't necessarily indicate the causality of whatever generated those signals.
> get directed to a wikipedia page where it's answered
It's not answered in said page. If it was then I'd be discussing that answer, rather than continuing to ask for that answer. (Not to mention that just linking some Wikipedia page without any attempt at providing context is itself pretty dismissive, but whatever)
Specifically, the "answer" in that page only seems to describe the situation where the signal in its own reference frame is actually travelling faster than c, whereas the very premise of things like warp drives is to, you know, warp spacetime such that the distance covered in that signal's own reference frame is substantially shorter than normal.
That is: a tachyonic antitelephone assumes that, you know, the signal exists as tachyons. Citing the concept of a tachyonic antitelephone in the context of a discussion around warping spacetime to shorten the distance entirely (i.e. remove the reliance on tachyons entirely) suggests - to me, at least, with my dumb dropout monkey brain - some implication that any situation where a signal from Point A arrives at Point B (where A and B are, say, 1 lightsecond away) any sooner than 1 second after being sent from Point A necessitates that signal to be treated as tachyonic, no matter what the signal "perceives" in its own reference frame. Thus, my question: why?
And if you can't answer that question, then that's perfectly fine! I can't answer that question, either, so it ain't like I'd hold it against you. But if you're going to take the time to dismiss that question as being stupid or misguided or what have you, the least you could do is attempt to explain why it's a stupid question - or, better yet, just answer the question.
> Pop science books are a thing, try those instead?
Would you care to recommend one?
> But combining that with "oh why am I getting downvoted and dismissed" wailing seems disingenuous though.
If you actually believed me to be the disingenuous one in this conversation, then why bother continuing to comment? If you don't have anything to contribute, and don't believe I have anything to contribute, then, you could always, you know, leave me to my ignorant wailing :)
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Misconception: > because the only way to go back in time is to have a speed greater than infinity > Instead of an answer, it seems like today I'll be getting downvotes and ad hominem dismissals. Oh well. Probably because your approach is very confrontational for someone who claims to be "just asking questions" e.g. "unsound", "not remotely adequate". And then you're dismissive - get directed to a wikipedia page where…
> because the only way to go back in time is to have a speed greater than infinity And how is that a misconception? That seems to be exactly the thing the "answers" describe: the time it takes to travel from point A to point B being negative, somehow . Even when discussing problems where we've defined that duration to be positive . > Probably because your approach is very confrontational Just because you perceive it…
Yes, I see that you're capable of being confrontational all day, and unwilling to follow up via clicking links on your own. Why don't you find someone else to troll?