6 ms·

For sure, but isn’t this already the most important leap we needed? That we can imagine that it’s at least theoretically possible? In all this excitement hopef

For sure, but isn’t this already the most important leap we needed? That we can imagine that it’s at least theoretically possible? In all this excitement hopefully we don’t forget the horde of luddites that’s the modern physics community that couldn’t imagine the possibility of faster than light travel. Like I get it, it’s absurd to consider FTL in regular space time, but when a normal person asks this question all they care about is whether they can realistically imagine going from one star to another in meaningful timespans. Pretty much every physicist I talked to online and offline would scoff and call the concept “absurd” (which is technically true in regular space time). I even believed them for a while. They’d shut down any discussion or imagination before it was even possible. Even now you see the same backwards thinking instead of being excited at least by the theoretical possibility. Even last year when I brought up the Alcubierre drive to a physics PhD he wasn’t aware of it, and couldn’t imagine this being anything other than a joke (even after showing him the Wikipedia page). Like a bunch of science fiction writers could think of something called “warp drive” and it took decades for some dude in Mexico to imagine a theoretical potential method to do this? The last great physicist in my opinion is Carl Sagan, the entire field just like most sciences have rotten to the core into completely unimaginative folks who cannot fathom a world that’s only marginally different from what’s currently around them. Richard Rhodes spends a lot of time in his “making of the atomic bomb” to figure out if the original inspiration for the atom bomb might have come from HG Wells. We’ve had great imagination in our science fiction, only our scientists have lost whatever mojo used to be there (and I suppose a gun to the head in the name of Nazism) to inspire from it.

tshaddox 5y ago
Is the notion that we could create a craft that travels faster than the speed of flight more absurd, less absurd, or equally as absurd as the notion that we could create a perpetual motion machine?
- ramraj07 5y ago
  From my current understanding, it’s less absurd. Again the pedantic ones would say this is still not FTL but again to them who cares? We are not breaking laws of physics and we get from point a to point b fast.
  - wiml 5y ago
    No matter how we do it, we end up violating causality. Even if we can only create micron-sized warp drives, there are still some huge implications. We could probably build a machine that executes nondeterministic algorithms, for example — doesn't matter that P≠NP if we nevertheless have a way to solve such problems in P time.
    - dane-pgp 5y ago
      I've also wondered about the implications of a causality-violating miniature warp field, and the hypothetical application I found most intriguing is the possibility of it allowing information to be sent back in time from the future. Of course it would have the limitation that you could only send information back to a point after the "time machine" had been switched on, and you could only communicate to entities in the future who knew of your time machine's existence and design, but that's enough of a pinhole to send lottery numbers back through. This has probably been considered before in fiction, where presumably the author thought about the other practical problems, like the time machine being on a rotating and Sun-orbiting Earth, meaning that the spatial distance between the time machine's location on subsequent days can be considerably large (relative to reference frame of the Sun). I don't know what the engineering consequences of that are.
      - echelon 5y ago
        I think about this a lot. It definitely steps around P=NP. You could try a large number of costly experiments and "send back" the working solution. The parallel experiments collapse into one. You can send canary messages back to yourself to know if you're in danger, assuming it's you on the other side. But perhaps the signals from the future are actually from an advanced adversary, such as an AI, and they're telling you to make moves that will lead to your demise (or the rise of the adversary). The future adversary knows your actions and can send crafted messages to nudge you to the desired outcome. Perhaps similarly to the "P=NP" parallel explorations in the future from the past, the future has parallel simulations of your past behavior to optimize the future outcome. It breaks the rules, but it'd be fun fiction.
      - 5y ago
p2t2p 5y ago
There were times when physics PhDs would chuckle and say absurd about going faster than sound. The equations that we had back then also predicted all kind of infinities in pressure, etc.
- Eelongate 5y ago
  > There were times when physics PhDs would chuckle and say absurd about going faster than sound. Oh come on now, that's obvious bullshit. The term "sound barrier" doesn't predate the 20th century and was only popularized during WWII. Any physicist claiming it was a fundamental limitation would've needed to be completely ignorant to the existence of artillery. Who were these supposed physicists and what specifically did they claim?
  - p2t2p 5y ago
    Prandtl–Glauert singularity https://en.wikipedia.org/wiki/Prandtl–Glauert_singularity https://en.wikipedia.org/wiki/Prandtl–Glauert_singularity > The Prandtl–Glauert singularity is a theoretical construct in flow physics, often incorrectly used to explain vapor cones in transonic flows. It is the prediction by the Prandtl–Glauert transformation that infinite pressures would be experienced by an aircraft as it approaches the speed of sound. Because it is invalid to apply the transformation at these speeds, the predicted singularity does not emerge. > The incorrect association is related to the early-20th-century misconception of the impenetrability of the sound barrier. I learnt about it from Destin's video: https://youtu.be/p1PgNbgWSyY?t=816 https://youtu.be/p1PgNbgWSyY?t=816
    - ben_w 5y ago
      Anyone using that formula must have either (1) known that the formula was inaccurate at that airspeed, or (2) denied the existence of supersonic shells and bullets. Likewise today, we know something is wrong with the combination {relativity, quantum mechanics} because if our formula for both were completely true, the universe wouldn’t exists. The supersonic munitions of the era were rather difficult to ignore, so you need better evidence to claim PhDs would’ve laughed at the idea, than merely that the best formula they had at the time was not good enough.
Andrew_nenakhov 5y ago
I don't even get why Alcubierre drives are called like that - this very concept was described in great detail in a rare soviet space opera "Humans as gods" [1] by Sergey Snegov written in 1960s. [1]: https://en.m.wikipedia.org/wiki/Humans_as_Gods https://en.m.wikipedia.org/wiki/Humans_as_Gods
- FeepingCreature 5y ago
  Coming up with the concept isn't particularly important. Alcubierre actually did the math.
- wiml 5y ago
  Alcubierre was the first person to connect this idea to a spacetime metric which obeys the equations of general relativity, with actual math.
- causi 5y ago
  If you don't need the self-consistent mathematical theory behind it you should call it the Campbell warp drive, since John W. Campbell laid out the mechanism in 1957. Indeed, you could even call it the Brown warp drive, after the first use of the term "space-warp drive" by Fredric Brown in 1949.
generalizations 5y ago
There's a lot of science that was discovered by people who had the ability to devote their time and energy to discovery for it's own sake. There's no reason academia and research labs should have a monopoly on such opportunities these days. All it really takes is burn time, dedication and intelligence. Why don't some of us just spend our time on these kinds of things? Far as I can tell, the equipment expense is well within the budget of a co-op of well paid tech folks.
- ramraj07 5y ago
  Absolutely. I’m a biologist myself but I NOped out of academia with my PhD. Just making my money now before I establish my own garage lab to study connectomics.
wh313 5y ago
> In all this excitement hopefully we don’t forget the horde of luddites that’s the modern physics community that couldn’t imagine the possibility of faster than light travel. https://doi.org/10.1007%2Fs10701-011-9539-2 https://doi.org/10.1007%2Fs10701-011-9539-2 - cited 57 times https://doi.org/10.1088/1361-6382/aafcea https://doi.org/10.1088/1361-6382/aafcea - cited 47 times https://doi.org/10.1103/PhysRevD.56.2100 https://doi.org/10.1103/PhysRevD.56.2100 - cited 123 times Each of these papers propose a separate method of faster-than-light travel. Where's the lack of imagination? > Like I get it, it’s absurd to consider FTL in regular space time, but when a normal person asks this question all they care about is whether they can realistically imagine going from one star to another in meaningful timespans. Pretty much every physicist I talked to online and offline would scoff and call the concept “absurd” (which is technically true in regular space time). I even believed them for a while. They’d shut down any discussion or imagination before it was even possible. Even now you see the same backwards thinking instead of being excited at least by the theoretical possibility. Even last year when I brought up the Alcubierre drive to a physics PhD he wasn’t aware of it, and couldn’t imagine this being anything other than a joke (even after showing him the Wikipedia page). What's the difference between "regular" and "non-regular" spacetime? Also, maybe the physicists you talked to worked in other subfields of physics and didn't have expertise in this topic? Imagine going up to a professor in computer networking and asking what they think about the P=NP problem. > Like a bunch of science fiction writers could think of something called “warp drive” and it took decades for some dude in Mexico to imagine a theoretical potential method to do this? A bunch of science fiction writers also thought up of something called "transporters" and we have no way of making it real. Another group came up with PADDs and we have them now. You're cherrypicking one data point and generalizing it. > The last great physicist in my opinion is Carl Sagan, the entire field just like most sciences have rotten to the core into completely unimaginative folks who cannot fathom a world that’s only marginally different from what’s currently around them. Roger Penrose is still alive, and has a Nobel Prize in physics. We also took a picture of a black hole two years ago. Isn't that a great scientific achievement as well? It seems as though you're mistaking Sagan's scientific outreach efforts for actual scholarship on the subject. I suppose what I'm trying to say is that I see the opposite of what you do in academia. For me, it seems to be still working well. Sure, there's still weird politics and worrying about being scooped, but ideas that are credible won't be shot down, but anything that doesn't make sense would be ripped to shreds.
analog31 5y ago
I'm a physicist, and I think FTL is easy to imagine. In fact, I think that if it's possible, it'll be here sooner than we think, like maybe four or five years ago.
- MrYellowP 5y ago
  > like maybe four or five years ago. Hhhmmmm...
  - analog31 5y ago
    I was making a back-handed reference to the idea that FTL travel, and erasing the distinction between past and future, are similar ideas. ;-)
light_hue_1 5y ago
> Richard Rhodes spends a lot of time in his “making of the atomic bomb” to figure out if the original inspiration for the atom bomb might have come from HG Wells. Nonsense. Szilard thought chain reactions were possible and worked years to prove this is the case. The bomb was an immediate and obvious consequence. Science fiction writers don't push physics or science forward. Physics and science push science fiction forward. As we discover more, what we can imagine also grows. > Like a bunch of science fiction writers could think of something called “warp drive” and it took decades for some dude in Mexico to imagine a theoretical potential method to do this? People 5,000 years go could imagine flying. But that doesn't help you with flying at all. Just because someone wrote a cute story about how nice it would be to fly, doesn't mean you're any closer to doing it.
- ramraj07 5y ago
  Szilard knew Wells very closely and definitely read Wells work which talks about atom bombs dictating the world order in the fifties. He says himself that it didn’t exactly seed the thought but I find that hard to believe personally. This doesn’t take anything away from him, if that’s somehow offending you. The correct analogy is about how long you go from someone imagining a flying machine where the wings don’t move to an actual plane. They called it “warp drive” for heavens sake. Also comparing the lack of progress today to the lack of progress in medieval times is not the flex you think it is.
  - light_hue_1 5y ago
    > The correct analogy is about how long you go from someone imagining a flying machine where the wings don’t move to an actual plane. They called it “warp drive” for heavens sake. No way. The idea that your wings don't have to move wasn't new, it's ancient. People were building paper planes thousands of years ago. If all it took to fly is to not move your wings, people would have been flying around thousands of years ago. Making a flying machine takes far more than that. You need to understand the lift equation, how airfoils work, how and why you can and can't control wings and attitude, etc. The Wright brothers didn't strap wings to a bicycle, they spent years working on the physics and engineering of flight, including building wind tunnels. From the outside, at a high level, without understanding the physics or engineering of these systems, it's easy to say "Oh, it's just X". Like looking at the solution to a chess problem and saying "Of course, I would have seen that". You wouldn't have. As evidenced by the fact that no one did. For millenia. > Also comparing the lack of progress today to the lack of progress in medieval times is not the flex you think it is. I never said there's a lack of progress today. Scientific progress is amazing today, far faster today than at any point in history.
lvs 5y ago
You know, you're getting downvoted a lot, but there's a sense in which I agree in part and disagree in part. On the disagreement side, what is the purpose of being caught up in this exuberance for something widely considered to be possible only if something else impossible becomes possible? On the agreement side, the sciences have become unimaginative because they have become so competitive and careerist. In that context, people are encouraged to sell snake oil even just to tread water in the academic system. (It's much easier than actually doing serious honest work. And a more reliable career path!) In that context, there must be a sufficiently strong repressive skepticism, or else you just end up with unscientific fields full of unrigorous snake oil: like nutrition, nanotech, aging research, etc.
tzs 5y ago
> In all this excitement hopefully we don’t forget the horde of luddites that’s the modern physics community that couldn’t imagine the possibility of faster than light travel There's a kind of funny example of that involving Kip Thorne, or rather Kip Thorne's students. He ran into his friend Carl Sagan at some event--I think it was something like they arrived at the airport at the same time for some conference they were both attending and ended up sharing a cab [1]. At the time Sagan was writing his novel "Contact", needed FTL travel in it, and was hand waving away how that would be done. Sagan was aware the one of Thorne's pet peeves was science fiction that hand waved away things like that without at least trying to come up with something that might be plausible or at least wasn't known to be impossible. Sagan carefully broached the subject of "Contact" and that he was hand waving FTL in it, and asked if Thorne could come up with some justification for Sagan's FTL. That set Thorne onto researching wormholes for travel and he found solutions that didn't appear to be definitely physically impossible. Thorne wrote a guide to wormhole travel for Sagan to use to make "Contact" less hand-wavy. Thorne then put a problem on the final exam for Caltech's Ph 236, General Relativity, that set up the conditions for a pair of connected wormholes and asked the students to calculate what would happen. Most students got that you would get a pair of connected wormholes, but Thorne was disappointed that none of the students had noticed that this seems to give a way for FTL travel. [1] I'm going by memories of reading drafts of a book Thorne was working on 40 years ago so details are a little fuzzy. He was writing a book for the general public that was going to be about contemporary physicists. Each chapter was going to feature an interview by Thorne of a contemporary physicist and an explanation of their work. Thorne had his notes, interviews, and draft chapters on his account at the VAX of the Caltech High Energy Physics department, and it was world readable so was widely read by the other people with accounts on the machine. It's too bad it never came out. My recollection was it looked like it was going to be very interesting.

tshaddox 5y ago

Is the notion that we could create a craft that travels faster than the speed of flight more absurd, less absurd, or equally as absurd as the notion that we could create a perpetual motion machine?

ramraj07 5y ago
From my current understanding, it’s less absurd. Again the pedantic ones would say this is still not FTL but again to them who cares? We are not breaking laws of physics and we get from point a to point b fast.
- wiml 5y ago
  No matter how we do it, we end up violating causality. Even if we can only create micron-sized warp drives, there are still some huge implications. We could probably build a machine that executes nondeterministic algorithms, for example — doesn't matter that P≠NP if we nevertheless have a way to solve such problems in P time.
  - dane-pgp 5y ago
    I've also wondered about the implications of a causality-violating miniature warp field, and the hypothetical application I found most intriguing is the possibility of it allowing information to be sent back in time from the future. Of course it would have the limitation that you could only send information back to a point after the "time machine" had been switched on, and you could only communicate to entities in the future who knew of your time machine's existence and design, but that's enough of a pinhole to send lottery numbers back through. This has probably been considered before in fiction, where presumably the author thought about the other practical problems, like the time machine being on a rotating and Sun-orbiting Earth, meaning that the spatial distance between the time machine's location on subsequent days can be considerably large (relative to reference frame of the Sun). I don't know what the engineering consequences of that are.
    - echelon 5y ago
      I think about this a lot. It definitely steps around P=NP. You could try a large number of costly experiments and "send back" the working solution. The parallel experiments collapse into one. You can send canary messages back to yourself to know if you're in danger, assuming it's you on the other side. But perhaps the signals from the future are actually from an advanced adversary, such as an AI, and they're telling you to make moves that will lead to your demise (or the rise of the adversary). The future adversary knows your actions and can send crafted messages to nudge you to the desired outcome. Perhaps similarly to the "P=NP" parallel explorations in the future from the past, the future has parallel simulations of your past behavior to optimize the future outcome. It breaks the rules, but it'd be fun fiction.
    - 5y ago

p2t2p 5y ago

There were times when physics PhDs would chuckle and say absurd about going faster than sound. The equations that we had back then also predicted all kind of infinities in pressure, etc.

Eelongate 5y ago
> There were times when physics PhDs would chuckle and say absurd about going faster than sound. Oh come on now, that's obvious bullshit. The term "sound barrier" doesn't predate the 20th century and was only popularized during WWII. Any physicist claiming it was a fundamental limitation would've needed to be completely ignorant to the existence of artillery. Who were these supposed physicists and what specifically did they claim?
- p2t2p 5y ago
  Prandtl–Glauert singularity https://en.wikipedia.org/wiki/Prandtl–Glauert_singularity https://en.wikipedia.org/wiki/Prandtl–Glauert_singularity > The Prandtl–Glauert singularity is a theoretical construct in flow physics, often incorrectly used to explain vapor cones in transonic flows. It is the prediction by the Prandtl–Glauert transformation that infinite pressures would be experienced by an aircraft as it approaches the speed of sound. Because it is invalid to apply the transformation at these speeds, the predicted singularity does not emerge. > The incorrect association is related to the early-20th-century misconception of the impenetrability of the sound barrier. I learnt about it from Destin's video: https://youtu.be/p1PgNbgWSyY?t=816 https://youtu.be/p1PgNbgWSyY?t=816
  - ben_w 5y ago
    Anyone using that formula must have either (1) known that the formula was inaccurate at that airspeed, or (2) denied the existence of supersonic shells and bullets. Likewise today, we know something is wrong with the combination {relativity, quantum mechanics} because if our formula for both were completely true, the universe wouldn’t exists. The supersonic munitions of the era were rather difficult to ignore, so you need better evidence to claim PhDs would’ve laughed at the idea, than merely that the best formula they had at the time was not good enough.

Andrew_nenakhov 5y ago

I don't even get why Alcubierre drives are called like that - this very concept was described in great detail in a rare soviet space opera "Humans as gods" [1] by Sergey Snegov written in 1960s. [1]: https://en.m.wikipedia.org/wiki/Humans_as_Gods https://en.m.wikipedia.org/wiki/Humans_as_Gods

FeepingCreature 5y ago
Coming up with the concept isn't particularly important. Alcubierre actually did the math.
wiml 5y ago
Alcubierre was the first person to connect this idea to a spacetime metric which obeys the equations of general relativity, with actual math.
causi 5y ago
If you don't need the self-consistent mathematical theory behind it you should call it the Campbell warp drive, since John W. Campbell laid out the mechanism in 1957. Indeed, you could even call it the Brown warp drive, after the first use of the term "space-warp drive" by Fredric Brown in 1949.

generalizations 5y ago

There's a lot of science that was discovered by people who had the ability to devote their time and energy to discovery for it's own sake. There's no reason academia and research labs should have a monopoly on such opportunities these days. All it really takes is burn time, dedication and intelligence. Why don't some of us just spend our time on these kinds of things? Far as I can tell, the equipment expense is well within the budget of a co-op of well paid tech folks.

ramraj07 5y ago
Absolutely. I’m a biologist myself but I NOped out of academia with my PhD. Just making my money now before I establish my own garage lab to study connectomics.

wh313 5y ago

> In all this excitement hopefully we don’t forget the horde of luddites that’s the modern physics community that couldn’t imagine the possibility of faster than light travel. https://doi.org/10.1007%2Fs10701-011-9539-2 https://doi.org/10.1007%2Fs10701-011-9539-2 - cited 57 times https://doi.org/10.1088/1361-6382/aafcea https://doi.org/10.1088/1361-6382/aafcea - cited 47 times https://doi.org/10.1103/PhysRevD.56.2100 https://doi.org/10.1103/PhysRevD.56.2100 - cited 123 times Each of these papers propose a separate method of faster-than-light travel. Where's the lack of imagination? > Like I get it, it’s absurd to consider FTL in regular space time, but when a normal person asks this question all they care about is whether they can realistically imagine going from one star to another in meaningful timespans. Pretty much every physicist I talked to online and offline would scoff and call the concept “absurd” (which is technically true in regular space time). I even believed them for a while. They’d shut down any discussion or imagination before it was even possible. Even now you see the same backwards thinking instead of being excited at least by the theoretical possibility. Even last year when I brought up the Alcubierre drive to a physics PhD he wasn’t aware of it, and couldn’t imagine this being anything other than a joke (even after showing him the Wikipedia page). What's the difference between "regular" and "non-regular" spacetime? Also, maybe the physicists you talked to worked in other subfields of physics and didn't have expertise in this topic? Imagine going up to a professor in computer networking and asking what they think about the P=NP problem. > Like a bunch of science fiction writers could think of something called “warp drive” and it took decades for some dude in Mexico to imagine a theoretical potential method to do this? A bunch of science fiction writers also thought up of something called "transporters" and we have no way of making it real. Another group came up with PADDs and we have them now. You're cherrypicking one data point and generalizing it. > The last great physicist in my opinion is Carl Sagan, the entire field just like most sciences have rotten to the core into completely unimaginative folks who cannot fathom a world that’s only marginally different from what’s currently around them. Roger Penrose is still alive, and has a Nobel Prize in physics. We also took a picture of a black hole two years ago. Isn't that a great scientific achievement as well? It seems as though you're mistaking Sagan's scientific outreach efforts for actual scholarship on the subject. I suppose what I'm trying to say is that I see the opposite of what you do in academia. For me, it seems to be still working well. Sure, there's still weird politics and worrying about being scooped, but ideas that are credible won't be shot down, but anything that doesn't make sense would be ripped to shreds.

analog31 5y ago

I'm a physicist, and I think FTL is easy to imagine. In fact, I think that if it's possible, it'll be here sooner than we think, like maybe four or five years ago.

MrYellowP 5y ago
> like maybe four or five years ago. Hhhmmmm...
- analog31 5y ago
  I was making a back-handed reference to the idea that FTL travel, and erasing the distinction between past and future, are similar ideas. ;-)

light_hue_1 5y ago

> Richard Rhodes spends a lot of time in his “making of the atomic bomb” to figure out if the original inspiration for the atom bomb might have come from HG Wells. Nonsense. Szilard thought chain reactions were possible and worked years to prove this is the case. The bomb was an immediate and obvious consequence. Science fiction writers don't push physics or science forward. Physics and science push science fiction forward. As we discover more, what we can imagine also grows. > Like a bunch of science fiction writers could think of something called “warp drive” and it took decades for some dude in Mexico to imagine a theoretical potential method to do this? People 5,000 years go could imagine flying. But that doesn't help you with flying at all. Just because someone wrote a cute story about how nice it would be to fly, doesn't mean you're any closer to doing it.

ramraj07 5y ago
Szilard knew Wells very closely and definitely read Wells work which talks about atom bombs dictating the world order in the fifties. He says himself that it didn’t exactly seed the thought but I find that hard to believe personally. This doesn’t take anything away from him, if that’s somehow offending you. The correct analogy is about how long you go from someone imagining a flying machine where the wings don’t move to an actual plane. They called it “warp drive” for heavens sake. Also comparing the lack of progress today to the lack of progress in medieval times is not the flex you think it is.
- light_hue_1 5y ago
  > The correct analogy is about how long you go from someone imagining a flying machine where the wings don’t move to an actual plane. They called it “warp drive” for heavens sake. No way. The idea that your wings don't have to move wasn't new, it's ancient. People were building paper planes thousands of years ago. If all it took to fly is to not move your wings, people would have been flying around thousands of years ago. Making a flying machine takes far more than that. You need to understand the lift equation, how airfoils work, how and why you can and can't control wings and attitude, etc. The Wright brothers didn't strap wings to a bicycle, they spent years working on the physics and engineering of flight, including building wind tunnels. From the outside, at a high level, without understanding the physics or engineering of these systems, it's easy to say "Oh, it's just X". Like looking at the solution to a chess problem and saying "Of course, I would have seen that". You wouldn't have. As evidenced by the fact that no one did. For millenia. > Also comparing the lack of progress today to the lack of progress in medieval times is not the flex you think it is. I never said there's a lack of progress today. Scientific progress is amazing today, far faster today than at any point in history.

lvs 5y ago

You know, you're getting downvoted a lot, but there's a sense in which I agree in part and disagree in part. On the disagreement side, what is the purpose of being caught up in this exuberance for something widely considered to be possible only if something else impossible becomes possible? On the agreement side, the sciences have become unimaginative because they have become so competitive and careerist. In that context, people are encouraged to sell snake oil even just to tread water in the academic system. (It's much easier than actually doing serious honest work. And a more reliable career path!) In that context, there must be a sufficiently strong repressive skepticism, or else you just end up with unscientific fields full of unrigorous snake oil: like nutrition, nanotech, aging research, etc.

tzs 5y ago

> In all this excitement hopefully we don’t forget the horde of luddites that’s the modern physics community that couldn’t imagine the possibility of faster than light travel There's a kind of funny example of that involving Kip Thorne, or rather Kip Thorne's students. He ran into his friend Carl Sagan at some event--I think it was something like they arrived at the airport at the same time for some conference they were both attending and ended up sharing a cab [1]. At the time Sagan was writing his novel "Contact", needed FTL travel in it, and was hand waving away how that would be done. Sagan was aware the one of Thorne's pet peeves was science fiction that hand waved away things like that without at least trying to come up with something that might be plausible or at least wasn't known to be impossible. Sagan carefully broached the subject of "Contact" and that he was hand waving FTL in it, and asked if Thorne could come up with some justification for Sagan's FTL. That set Thorne onto researching wormholes for travel and he found solutions that didn't appear to be definitely physically impossible. Thorne wrote a guide to wormhole travel for Sagan to use to make "Contact" less hand-wavy. Thorne then put a problem on the final exam for Caltech's Ph 236, General Relativity, that set up the conditions for a pair of connected wormholes and asked the students to calculate what would happen. Most students got that you would get a pair of connected wormholes, but Thorne was disappointed that none of the students had noticed that this seems to give a way for FTL travel. [1] I'm going by memories of reading drafts of a book Thorne was working on 40 years ago so details are a little fuzzy. He was writing a book for the general public that was going to be about contemporary physicists. Each chapter was going to feature an interview by Thorne of a contemporary physicist and an explanation of their work. Thorne had his notes, interviews, and draft chapters on his account at the VAX of the Caltech High Energy Physics department, and it was world readable so was widely read by the other people with accounts on the machine. It's too bad it never came out. My recollection was it looked like it was going to be very interesting.