Interstellar also attempts to be very scientific about space travel. (Or at least so the early news and promotional material about it tried to claim.) It does an admirable job of that for about the first 25% of the movie. After which my expectations had been set high enough that the remaining 75% brutalized my suspension of disbelief.
Interstellar also attempts to be about the human condition. Some of which it does at the expense of the aforementioned sciency stuff.
People who know or care less about about sciency details will probably enjoy the movie more than i did, but i'm enough of a hard core SF geek that when something gives the impression of trying to be scientific the margin of error i'm willing to grant it contracts drastically. If that scene with Sandra Bullock trying to catch that guy before he "fell" away bothered you, then Interstellar may drive you as batty as it did me.
And since this turned into a huge rant, here's the short version of what bothered me about the movie:
1: Horrible orbital dynamics, as exemplified by
2: Ludicrously impossible fuel/weight ratios, to escape from
3: Poorly explained or just plain wrong ecologic disasters, which will be "solved" via a
4: Poor understanding of the relationship between science and engineering, which was brought about by
5: The power of love as a cosmos spanning fundamental force (and also performing impossible tricks with gravity.)
The fact that the people themselves were occasionally really stupid on top of that hardly even registers.
And now, the full (very very long) rant, which also doubles as a rather poor synopsis of the movie.
There were actually a couple issues in the first 25% that bothered me, but they were either non-spacey or explainable.
What the hell happened to Earth? It's left intentionally vague, but between what's stated outright and what's implied it seems that it wasn't global warming. (I wonder if Nolan intentionally avoided that for fear of the movie getting enmeshed in political debates.) Supposedly people used to be afraid of running out of resources, but instead they ran out of food. This is backed up by the fact that everyone is still driving around in what are clearly "old" gas powered cars. (They make sure you can hear the engines rumbling at several points.)
The problem with food is that there's some kind of blight infecting crops. We're told that wheat was killed off early. We see the last crop of okra being burned because it's been infected by blight. Now everyone is growing corn. Given the theme of the movie we're soon told that sooner or later the blight is inevitably going to infect the corn too, and then everyone will starve to death.
And then we're also told that the blight thrives in a nitrogen environment, as the blight kills more plants the amount of nitrogen in the air increases and the more the blight spreads. There was some quip about how the last people to starve would be the first people to suffocate or something like that.
The problem: Perhaps someone with with more knowledge can correct me on this, but nitrogen does not play nearly as large a role in plant biology as carbon dioxide. A lot of crop plants pull nitrogen _out_ of the soil, which is part of why farmers have to rotate fields and let them go fallow for awhile or alternate them with nitrogen fixing plants. If the blight killed off all crops if anything the net effect would probably be a slight _decrease_ in atmospheric nitrogen. If it did kill off enough plants (not just crops) it would eventually kill all the humans, but due to an excess of CO2 and a lack of O2, not due to anything involving nitrogen.
Another problem facing humanity is a return of the dust bowl. There's dust everywhere and giant dust storms that come around from time to time. The issue is they don't seem to have any trouble growing crops, aside from the blight itself. And there's no evidence of a massive irrigation system. How are they able to grow plants so easily if it's so dry? If it's not so dry why aren't there native grasses holding down the soil in the areas they're not farming?
Should we believe that the blight took out all the other plants before it got around to the crops? That seems... unlikely. Even more unlikely than a blight that can apparently infect plants across multiple species boundaries to begin with. It does make sense that the blight would attack human crops first, since those are much more of a monoculture. But if it attacks them first then the whole dust bowl situation and concern about everyone suffocating doesn't make much sense.
Are we to assume that along with the mentioned wheat and okra and the kind of implied potatoes, that the blight has also taken out rice, yams, beans, and every other food crop as well?
If corn really is the only staple food crop left, hard to believe as that is, then where are all the animals? We never see a single animal in the movie, no cows, no pigs, no horses, no cats, no dogs. If humans were having trouble with food crops i would expect to see a lot of land devoted to alfalfa and hay and anything else they could grow to feed to huge herds of cows and pigs and whatever. Going back to a herder lifestyle isn't very efficient, but if all the food crops are failing it would make sense.
And of course there's the whole question of GMO and breeding. Are they not trying to breed or create plants resistant to the blight? I know the world has gone a bit anti-science, but that seems a little extreme given the situation. Or have they been modifying the food crops all this time and the movie just didn't see fit to mention it? (That might make the theory of all the other plants having been killed off before corn a little more believable.)
All in all there are too many questions about the whole environmental situation on earth for it to make much sense. But okay, we can handwave that away because that's not the point of the movie. The point of the movie is space!
So the hero and his daughter get to the NASA lab, and the old distinguished scientist guy ask the hero guy if he noticed anything about the launching facility. Oh look! It's all circular, as if it was meant to be spun up! Indeed, ever since finding out about the gravitational waves from the wormhole they've been researching gravity. As soon as they "solve" gravity they're going to launch the whole thing as a space habitat.
Wait a second, if you've "solved" gravity, allowing you to feasibly launch an entire space habitat in one go, then why do you need to spin it for artificial gravity? I'm willing to give this one a pass however on the theory that generating false gravity is energy intensive enough to not be cost-effective for providing an entire space colony with a 1G field for 24 hours a day, while still being orders of magnitude cheaper and easier than building launch rockets. It would have been nice if they'd dropped some hint about the logic there though.
But wait a second again, if you've got your space colony ready to go and all you need is a way to get it off the ground... then why do you need to get it off the ground?
If the problem is the environment on earth then you can seal out the environment a lot easier than you launch a space colony. The tricky part of building an independent space station is creating a self-contained biosphere. The reason you'd want to do so in space is because of access to off-world resources. However it was established earlier than the earth is _not_ suffering from a lack of resources, but a lack of food. So what the hell?
But anyways, in case they can't solve the gravity equation their backup plan is to send a team to the new system, where they'll try to follow up on the reports of the initial explorers and find a habitable planet to set up shop on, taking with them a bunch of frozen embryos.
So, hero guy is made the pilot takes off from earth with lady astronaut, other guy astronaut, other other guy astronaut, and a boxy looking robot (leaving his daughter behind to be mentored by old scientist guy and eventually became lady scientist.) A giant three stage rocket launches their little shuttle, which rendezvouses with the previously constructed "Endurance" space craft in orbit above earth, which looks like a mini space station. (And also has another boxy robot aboard.)
They head off for the wormhole around Saturn, with a two year flight plan that takes them past Mars for a gravitational slingshot. Some people have nit-picked the length of that voyage, but it was close enough to the ballpark not to bother me.
They spin up the station for gravity, they go into suspended animation for most of the trip, they arrive, they go through the wormhole. All perfectly plausible. (As long as you ignore the bit about how they don't seem to have any large fuel tanks with them.)
Then they arrive at the new system. We were told that the wormhole granted access to 12 worlds, but that they'd only gotten signals back from three of them. It wasn't entirely clear to me if the wormhole led to a system with 12 planets, or if you could somehow vary your entry into the wormhole and wind up at different places. Since they never mentioned anything about it when entering the wormhole and all three target planets were in the system they ended up at i just assumed it was 12 planets in a single system. Not a big deal, but i wish it had been a little more clear.
Oh, another thing that it would have been nice to have been made clear before they arrived, the fact that there was a black hole in the system.
That seems like kind of a, excuse the expression, huge deal to just lightly drop into the conversation after arriving! "We could go to planet X, but that would be difficult because of how close it is to the black hole." How close it is to the what now???
So i'd heard mention of the fact that part of the drama of the movie was the concern about how long they would be away from earth due to relativistic effects. When i first heard that it wasn't immediately apparent to me why going through a wormhole would involve relativistic effects. (Wormholes of course being what you use to get _around_ relativity.) I have to admit that involving a black hole is both a neat and logical way to get relativistic effects into play without relativistic speeds getting involved.
Okay, so there's a black hole in this system. We've discovered that binary systems are fairly common and it's also common for them to have planetary systems. Having planets in stable orbits in habitable zones in a binary system is a little tricky, but we can let that slide.
Then while debating whether to explore the planet that is dangerously close to the black hole or go to one of the two planets farther away, the hero casually mentions something about "we can take a short cut around that neutron star".
WHAT? This is a trinary system with a black hole _and_ a neutron star _and_ presumably some kind of main sequence star because otherwise there wouldn't be any habitable planets at all? WHAT THE HELL KIND OF STELLAR SYSTEM IS THIS??!?!?!
And exactly how close is the neutron star to the black hole such that going around it is not only feasible but advisable?
So eventually they decide to explore the black hole planet, despite the fact that every hour on the surface is the equivalent of 7 years back on earth. It would seem to me that regardless of time being, well, relative, even if that planet turned out to be habitable (which seems very unlikely that close to a black hole) that it would be a very poor choice as a place to establish a new home for humanity.
At this point i also start thinking "wait, if the wormhole appeared about 50 years ago, i don't know how long it took them to launch the exploration ships, but the explorer can have been down on the surface for at _most_ 7 hours given the time dilation. How has she had time to not only analyze the status of the planet, but also make the multiple reports that were referred to?"
So they land, and it turns out that going to a planet that close to a black hole was a VERY bad idea, and the explorer they're looking for was killed by the massive tidal waves on the planet. But her initial favorable report somehow got bounced around and was echoed multiple times, which fooled them into thinking the reports were ongoing. Or something. I know the method of communication with the explorers was limited, but was attaching some kind of timestamp to the messages entirely out of the question? Really? And no one picked up on the coincidence that they'd received multiple identical messages over a period of what subjectively have been a couple hours or less?
So they landed on this planet in their little shuttle thing. Which must have been quite a trip, because the plan was to have Endurance stay outside of the time dilation. Realistically that would mean that the Endurance wouldn't be anywhere near the planet. But we'll let that slide. (This is getting to be a habit.) They land on the planet in their little shuttle thing. In the brief time the have to wander around outside they complain about how heavy it is, and a gravity of 130% of earth's is mentioned. Drama and danger ensues. Other other astronaut guy gets killed. They manage to take off in their little shuttle at the last minute and then speed up into orbit.
Wait, WHAT?!? This thing is fairly small as far as spacecraft go, but it still quite reasonably took them a three stage booster to get off of earth when they left! How the hell can that thing just take off from a planet with 130% the gravity and just casually glide up to orbit? And that's entirely ignoring the prospect of having to escape from the gravity of the black hole, which is extreme enough to cause the 1 hour to 7 year time dilation, in order to get back to the Endurance which is supposedly outside the range of that gravity.
This would be the point where i said to myself "fuck this, i can't count on anything in this movie making any sense." I'd foreseen the problem as they landed and was wondering what kind of explanation they were going to give but there was none. Apparently this other system is in some magical land where the laws of physics just don't apply. Oh, and let's not forget the thrashing the shuttle received at the hands of the tidal waves, which by all rights ought to have rendered it unable to survive either blasting off or any future attempts to undergo reentry at any other planet they visited.
So they get back to the mother ship and 20 some odd years have gone by, dramatically represented by other astronaut guy, who had stayed behind. We get the emotional scene where the hero gets to catch up on 20 years of messages from his family. Either the film skipped showing a lot of messages, or his kids "wrote" to him an average of about once every five or six years. But despite that it's perfectly good drama.
Then they have to decide which of the two remaining planets to go to. Lady astronaut pushed for option B, because her lover explored that planet, and she thinks they should go there even though he stopped signaling a couple years ago. She admits that she hopes to find him again even though it isn't realistic, but then says that love is the one thing that can transcend time and space. After all, if there wasn't some significance to love then when do we keep loving people after the die. So maybe the fact that she wants to go to that planet out of love is actually the universe trying to tell them something. So this movie that at one point i was lead to believe would be heavy on science is now arguing that there's a cosmological significance to love because evolution didn't provide out emotions with a built-in expiration date. Great.
The hero "wisely" overrides this emotional argument and instead they head toward the planet that they're still getting a signal from. The person who explored this planet was named "Mann", and we're told that he was the best and the brightest of all the explorers, and was the brave and courageous astronaut who inspired the other explorers to follow him into almost certain doom. So clearly if he says his planet is good it must be the best option, right?
They arrive and find what appears to be a cold and barren world, with layers of frozen clouds. They find the explorer ship, though it's not clear if it's actually on the surface or just a layer of solid cloud. They find Mann in hibernation and wake him up, and he starts sobbing with relief that someone came for him.
All the explorers knew that even if they survived landing on their planets that rescue might never come. Humanity is in dire straits and the first priority is finding a new home, not recovering the astronauts. Under those circumstances it's understandable that someone could be overcome by emotion after being on their own for years and then suddenly being rescued, but it still seemed a little odd that the "best and brightest" of them was now crying like a baby, and a little alarm bell started ringing in my head.
Once Mann is fully awake and recovered they talk to him about his results. He says there's a deeper layer to the planet that's habitable. Really, on planet whose top layers are so cold the clouds have implausibly frozen solid? It's not impossible, but those alarm bells were getting a little louder. He'd "mounted several expeditions", which sounded a little grandiose. He'd discovered life, possible intelligent life. They notice his robot companion was in pieces. (I guess every explorer got their own boxy robot companion.) Oh yes, he got damaged when he mistakenly analyzed hydrogen-something-or-other-dangerous-so
Somewhere in the middle of all this the old scientist guy back on earth dies. On his deathbed he tells lady scientist/daughter that he lied about the gravity equation. He "solved" it before the missions was even launched, and they can't use it. After he dies she verifies the solution, and explains that it's only half the equation, the other half depends on getting data from inside of a singularity, which is obviously impossible. (And self-aware observers of the movie will realize that of course this means that someone is going to find a way to get info out of the singularity.) One wonders why you'd call an equation "solved" if you're still missing half the answer. One also wonders how you specifically determine that the other half depends on data from inside a black hole. But anyways, this is all serving to delay things while building up suspense about what's going on with Mann.
So back on Mann's planet they start bringing down shuttle loads worth of equipment and supplies from the Endurance. They start doing this before anyone actually gets around to asking Mann to show them the habitable area. Even given total trust in Mann i'm not sure why you'd do that rather than locating the habitable area and taking the supplies there directly. (I'm also not sure why Mann wouldn't have moved to this theoretical habitable area long ago while waiting for someone else to show up.) It's a long walk, so Mann and the hero set off alone. Mann starts acting more and more erratic. I've long since started literally twitching with annoyance at how long they're dragging this out (at some point Avalyn actually whispered to me asking if i was alright) as they cut back and forth between the hero and Mann walking and some dramatic going on with the lady scientist back on earth.
Finally Mann reveals that he faked all the data because he was lonely and afraid and wanted to be rescued. He tries to kill the hero. The hero manages to send a broadcast out and the lady astronaut jumps in the second shuttle to come rescue him. Meanwhile the other astronaut guy is investigating the busted robot, finally!, which turns out to be booby trapped and explodes. Meanwhile Mann steals the other shuttle and flies up to the Endurance.
Lady astronaut picks up hero astronaut, they fly by the smoking remains of the explorer craft to pick up the main robot sidekick, who confirms that other guy astronaut was killed by the explosion. Meanwhile there's no one back on the Endurance to stop Mann from boarding and taking over. (I'm not sure what happened to the second sidekick robot, i lost track of what happened to him but apparently he wasn't on the Endurance.)
The chase after him but he gets there first. "Luckily" he doesn't know how to dock, screws it up, and causes an explosion. Which kills him, damages part of the Endurance, and sends it spinning and gradually dropping into the atmosphere.
It should be noted at this point that in the quest to save humanity the biggest obstacle was Mann, because Mann is cowardly, stupid, and short-sighted. I'm sure that's not supposed to be an Aesop.
Of course the other three (two humans and a robot) manage to pull of a daring docking maneuver. They slow the Endruance down, then fire the rockets to get it back up into orbit. But as soon as they achieve orbit they get a warning that they're now heading towards the black hole!
This is insane. There is no situation in which you can be in orbit around a planet, or even in something just resembling an orbit, fire your thrusters for a few seconds too long, and then find that you're accidentally leaving the planet and heading toward another body in the solar system. An orbit can be unstable, but it's not like walking on a tightrope. You can't just accidentally "fall off" into outer space. If that were so people would be able to get from ISS to the moon just by jumping.
So they the hero hatches this brilliant idea that they'll keep on approaching the black hole, but then accelerate when they get close to do a flyby and slingshot toward the last planet, since they don't have enough fuel left after the explosion and recovery to get there otherwise. Unfortunately that means using two of the three remaining shuttles as booter jets and ditching them as they pass the black hole.
The robot and the hero heroically sacrifice themselves by going down into the black hole in their shuttles. (The explanation for why this couldn't be done remotely and why they didn't have time to get back onboard before ditching them was very rushed.)
So the hero and the robot fall into the black hole, and of course manages to survive. The robot ends up we're not sure where and apparently is able to meet the creators of the wormhole and make the observations of the singularity needed to complete the gravity formula. The hero meanwhile is in a pseudo-4D representation of his daughter's old room, the one that she said was haunted as a child and then got him sent to the NASA base. We unsurprisingly discover that he was the source of the hauntings and the messages, since the one thing that can cross time and space is gravity, and in this place he is able to manipulate the gravity in that room across time and space. Oh yeah, and also something involving love. (Honestly my brain kind of blocked that out, i'm not sure if it was stated or just implied that love was what led him to the right points in time to send his messages.)
I didn't actually have too much of a problem with this. I can run with the surmise that there are "aliens" who either live in or have gained master over higher dimensions. For the sake of story i can even accept that this allows them to reach across time, and that by extension they can enable to do so as well.
The robot then relays the data on the singularity to the hero, who encodes it in binary form in the twitch of the second hand of a watch the daughter left on the bookshelf. The daughter notices the twitching of the second hand, takes it back to her lab, decodes the data, solves the other half of the gravity equation, and uses it to launch not just one but a number of space colonies.
The most important question i have here is, even accepting that the hero can use gravity to cause the second hand to twitch while it's in the room and he has access to it, how does he "encode" that data into the watch such that the second hand _continues_ to keep twitching even after she takes it back to her lab records the data later? I would happily have accepted this if she'd taken the time to decode the data in the room, or taken a video and decoded it later, but the actual situation makes no sense to me.
Next, exactly how much data was this? The robot did the conversion to binary for him, but even just recording that binary in morse code by twitching on "strings" of gravity seems like a tricky process, and it's a little surprising he didn't make any mistakes. We only saw about a quarter of a page of morse get written down by scientist lady, which isn't that much, though maybe she went on for pages and pages more. If the data was too long we get back to the question of how did he transcribe all that properly. If it was too short however we have to wonder why she needed observations from the black hole rather than figuring it out by trial and error via experimentation.
Though that also brings up the corollary question, how does just knowing the equation for gravity let you build a device to control it? Knowing E=mc^2 didn't inherently inform Einstein or anyone else how exactly to build a nuclear bomb. And the Manhattan project was able to build an atomic bomb without knowing _all_ the math involved. Remember, they had bets about what the exact yield would be, with the somewhat tongue-in-cheek option of "ignite the atmosphere and destroy the earth" as a possibility. For that matter, we have theoretically plausible designs for FTL spacecraft right now but we can't test those theories because our material sciences aren't advanced enough.
I already covered the issue of why they even needed the gravity equation if they could already build self-contained habitats, so there's only one remaining bit that bugs me. After the hero is rescued (after presumably being ejected from the black hole by the near-omnipotent aliens as an act of goodwill) he gets to meet his now 100+ year old lady scientist daughter. The have a reunion, and then she tells him he should go find lady astronaut, who because of the time dilation from flying past the black hole, is just now setting up shop on the new planet and could really use some help. We see scenes of lady astronaut finding the explorer ship, which has apparently been partially crushed by something, and then of her at the grave of her dead lover.
So the hero sneaks into a docking bay we saw earlier and steals one of the (several) spaceships stored there, and presumably reaches lady astronaut and lives happily ever after with her setting up the new colony.
So, uh, how did lady scientist know that lady astronaut had reached the planet? Had lady astronaut sent a report back, or was she just guessing? But in either case, they apparently know she's there and they have plenty of spaceships capable of reaching her, why haven't they sent people to go help already? If there isn't already an expedition on the way there ought to at least be one getting ready to depart and the hero ought to be able to just join up with it instead of having to steal a ship.