4 ms·

Warp drives do not violate the speed of causality; they change the geometry of causality.

SideburnsOfDoom 6y ago
> Warp drives change the geometry of causality. Those are all words, and that's about all there is to say about your comment.
- willis936 6y ago
  Why are you sharing your opinions about a mechanism when you don't even have a remote understanding of the basics?
  - SideburnsOfDoom 6y ago
    Indeed, why are you?
mclightning 6y ago
I'm not sure what that means but like the OP, I think any information transfer at FTL breaks causality. ref: http://www.physicsmatt.com/blog/2016/8/25/why-ftl-implies-time-travel http://www.physicsmatt.com/blog/2016/8/25/why-ftl-implies-ti...
kittiepryde 6y ago
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 and prolly go with a more intuitive, 'cause must preceded effect'(removing the information speed limit); I assume that's the confusion here.
- SideburnsOfDoom 6y ago
  > '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.
  - kittiepryde 6y ago
    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 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 ).
    - SideburnsOfDoom 6y ago
      > Why would FTL automatically invert causality? 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 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.htm https://chem.tufts.edu/answersinscience/relativityofwrong.ht...

> Warp drives change the geometry of causality. Those are all words, and that's about all there is to say about your comment.

willis936 6y ago
Why are you sharing your opinions about a mechanism when you don't even have a remote understanding of the basics?
- SideburnsOfDoom 6y ago
  Indeed, why are you?

mclightning 6y ago

I'm not sure what that means but like the OP, I think any information transfer at FTL breaks causality. ref: http://www.physicsmatt.com/blog/2016/8/25/why-ftl-implies-time-travel http://www.physicsmatt.com/blog/2016/8/25/why-ftl-implies-ti...

kittiepryde 6y ago

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 and prolly go with a more intuitive, 'cause must preceded effect'(removing the information speed limit); I assume that's the confusion here.

SideburnsOfDoom 6y ago
> '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.
- kittiepryde 6y ago
  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 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 ).
  - SideburnsOfDoom 6y ago
    > Why would FTL automatically invert causality? 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 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.htm https://chem.tufts.edu/answersinscience/relativityofwrong.ht...