Geoscience in Movies: Interstellar
OK, now Interstellar has taken a lot of hits for gaping plot holes, wooden dialogue, and some of the most annoying sound mixing since home movies of a wedding were run over by a loud DJ’s choice of heavy metal favorites. But there is some earth science hiding in there and as a public service, GG felt like wondering aloud about that. (Note that GG has not read The Science of Interstellar, but given that only 15 pages of a 260+ page book are dedicated to the two planets shown, he suspects there isn’t going to be a lot of justification). There are apt to be some spoilers (but, realistically, not very spoiler-y if you have seen the previews), so be forewarned.
Now an interesting aspect of this is that physicist Kip Thorne was involved with this from the start and apparently insisted that science be honored (the full interview with Science is interesting, as is the extensive comment stream following it). There was obviously a lot of work on black holes, time contraction, and wormholes, but earth science seems to have taken a back seat (ironic given the strong planetary science program at Thorne’s academic home).
The first planet (Miller’s planet) is supposedly just outside the event horizon of a spinning black hole; this is to create the plot device of losing a lot of time. On the planet the crew of the landing craft (sorry, Star Trek terminology seems appropriate) suddenly faces an enormous wave after wading about in hip deep water; there is no indication of any topography. And after surviving that wave they get stuck facing a second wave. What are these things?
Well, there are two possibilities. One is that this planet has some whopping big earthquakes and the tsunamis generated are really big, the other is that these are the tides. Neither works. First, tides. If there are two waves, then more than half a day has passed. Anybody noticed nightfall? Neither did GG. Second, this means this planet is rotating–quite a trick given its extreme tides. How this thing isn’t tidally locked is hard to fathom. But even so, you’d expect on a water world where all the land has been eroded away (which seems a likely basis, otherwise why land your craft in the middle of an ocean?) that the water would in essence fill an equipotential. Making the tide into a wave would be really hard: tidal bores and extreme tidal fluctuations on Earth require topography to channel ocean waters. How about the tsunami? Um, where did that water come from? Tsunamis have two parts: water is pulled into the wave crest, so it should seem like the tide is going way, way out before that big wave arrives. And then, how do you get a mountain of water to not break on 2 or 3 feet of water? Sorry, no way to prevent that. In essence, the bottom of the wave gets dragged back by topography as the top continues to blast along. This seems like a very hard wave to make. Next time you are in a bathtub, take a swing at it. Fill the tub to an inch or two and then try and make a wave a couple feet high (to scale to Interstellar, you probably need your wave to reach the ceiling). Best of luck.
Oh yeah, if this thing is rotating with this very high tidal force, there would be serious earth tides and almost certainly near-continuous earthquakes (hmm, now that might have made for an interesting ride). The tidal heating would probably be so high that volcanic and tectonic activity would be pretty likely.
On to the next planet (Mann’s planet), where clouds have frozen into glaciers. Um, really? Gosh, there are so many problems with this it is hard to figure out where to start. Just how are these things supported? Even very cold ice flows; should you somehow managed to make these things, they should collapse pretty quickly. Just how do you get something that looks like a nice cumulus cloud to be frozen ice? Some kind of superhuman ice sculptor? And if you did actually freeze a cloud in place, its density is pretty darn low. Good luck with walking around on that stuff. You pretty much have to postulate some kind of ice molecule that is stronger than nearly all earthly materials and less dense than air. Not an easy assignment.
It is kind of sad. Here Thorne and others have gone to the trouble to try and figure out what a black hole would look like, what a wormhole would look like, they introduce aspects of the General Theory of Relativity to an audience, but then fill the screen with such obvious junk that it is fair to ask, would an audience member walk out thinking that you could get time dilation or that you can have a monster tidal wave race around a planet? Why be so accurate on some science and utterly ignore other stuff? Really good science fiction writers don’t make that mistake.