Physicist Kip Thorne On the Physics of "Interstellar"

A review of Interstellar at Scientific American that was not entirely flattering of the film's scientific aspects caught the eye of Cal Tech physicist Kip Thorne, who served as a consultant on the movie, and has actually written a book on the physics depicted. He and SciAm writer Lee Billings ended up having a conversation about how the film deals with time travel, black holes, and more. A slice: I think the laws of physics very probably forbid warp drives and traversable wormholes. The research that has gone on over the past 25 years trying to determine whether its possible all point in negative directions, but it’s not a firmly closed door. So there are two issues here. One is that the laws of physics probably forbid it, but, gee, if they don’t, it would be great to have! The other is that the technology required to make a warp drive or a traversable wormhole is so far, far, far beyond the technology needed for a laser sail or a nuclear-pulse rocket that I would not be in favor of putting any significant resources into trying to develop it. Now, you may have small amounts of money—tens or hundreds of thousands of dollars—spent on this, but nothing is wrong with that. Peer-review, at least in the United States and in Europe, is too strong for there to be any danger of millions or billions of dollars being spent on these things. The technology required for wormholes is so far removed from our current and plausible near-future capabilities that to throw lots of money at it would almost certainly be a total boondoggle.

Comments

Re:So it is not an accurate Documentary Film?

[nine-times]

Yeah, the blog post seems a little insane to me. I get it when Neil deGrasse Tyson complains about things like, in some movie the Earth spins the wrong way, or if the constellations are wrong for the time that the movie takes place. He's nit-picking and he knows it. He's pointing out interesting scientific inconsistencies. It might possibly be educational, and he's showing off his knowledge and attention to detail, and whatever, that's fine.

But this guy is actually complaining that the movie depicts a stable wormhole that we can travel through. His problem with it is, scientifically, we have no reason to think that it's possible, though we don't strictly know. Did he think that either Christopher Nolan or the audience was not aware that we can't create wormholes?

Even in the movie, it's not depicted as something that's easy to create. But that's beside the point, really, since it's a science fiction movie that is just positing that such a thing is possible for the sake of building a plot around that supposition. It's like complaining about Jurassic Park on the grounds that, "It's unlikely that we'll ever be able to clone dinosaurs from ancient mosquitoes formed in amber." Or complaining about the movie E.T. because, "We've never been visited by extra-terrestrial life forms-- at least not so far, not as far as we know..."

Re:"Physics"

[Immerman]

Actually the whole point is that we have several theoretical constructs that should allow travel from A to B at speeds greater than lightspeed. All rely on the fact that special relativity only imposes a local speed limit: i.e. you can't travel faster than light *through space*. Nothing in it forbids the existence of short cuts (wormholes) that connect distant parts of the universe with drastically shorter paths. Nor does it forbid things like an Alcubierre warp drive, where you don't move at all through the space you're in, but instead move an isolated bubble of flat space through the surrounding space at arbitrary speeds, while leaving the contents of that bubble of space in free fall (Relativity imposes no speed limit on space itself.)

Both constructs have their weak spots, but so far every time someone comes up with something showing them to be "impossible" somoeone else comes up with a modified construct that removes the impossibility. And of course there's the little issue that if Special Relativity is correct then any method of getting between A and B faster than light can also be used to send information into your own past, which would wreak havoc with our understanding of causality. But then the whole "time passes in only one direction" thing is a serious weak spot in our current understanding of the universe as well, so it may be that it's only us that would have an objection to causality loops, and not the universe itself.

Where every construct falls flat on it's face is that we have absolutely no idea how to actually create such a thing - we're mathematically modeling the things we might be able to do if we had nuclear reactors while still living in the stone age. But then that's what our species does, we tell ourselves stories of things that have never existed, and then try to figure out how to make them exist. We did it when our ancestors imagined how useful a killing-stone with a long, light handle would be, and we do it today on a million different fronts. Only difference is today we do our imaginings with a level of mathematical precision that guarantees that, if our starting assumptions are true, then the thing we imagine can in principle be built, even if we don't know how to do so at present.