Roger M. Wilcox's review of

The Core

(First posted to Bad Movie Night in 2003.)

A word of advice if you ever find yourself in a special-effects-driven end-of-the-world movie: Don't go anywhere NEAR any major landmarks. In Armageddon, Paris got wiped out by a large asteroid fragment, with ground zero centered on the Eiffel tower. In The Core, both the Roman Colosseum AND San Francisco's Golden Gate Bridge get toasted by an electrostatic superstorm and a giant microwave beam from the sun because the Earth's magnetic field is breaking down.

The problem is, in the Real World ™, if the Earth's magnetic field really did shut down, the increase in the number of cosmic rays reaching the lower atmosphere would not be enough to cause any kind of "superstorm." Worse, the Earth's magnetic field does NOTHING to shield the planet from microwave radiation, so if the sun really DID produce a microwave beam capable of melting the Golden Gate Bridge (hah!), the failure of the geomagnetic field would make no difference whatsoever. And, despite the fact that this movie was kinda fun to watch if you put your brain on hold, these aren't the only "messy details" the movie got wrong for the sake of a snappy script:

*) Right at the beginning, our geophysics professor hero says that when sound waves travel from one medium to another, they change in frequency and wavelength. Pah, shows what YOU know. Vibrational waves will change in wavelength between two media where the speed of sound is different in each medium, but they will NOT change in frequency. So there.

*) One of the featured characters is a cyber-cracker who can hunt down and destroy every single file on the Internet containing keywords he's searching for. I find it amazing that every different FTP and HTTP server throughout the world — despite the differences in the server software they all run — has such a gaping security hole. Maybe every single Internet server program ever written allows administrative control if you log in with a password of "Joshua". Later in the film, he hacks into the One Master Computer System that controls the nation's electric power supply. I only wish the real electric power distribution network WAS so well-coordinated that power could be rerouted from a single location. We'd all get fewer accidental blackouts that way.

*) The reason the geomagnetic field is collapsing is because the entire outer (liquid metal) core of the Earth has stopped spinning. This has happened because a secret government weapon capable of causing earthquakes has inadvertently "thrown a monkey wrench" into the core's machinery. Thing is, the total energy bound up in the core's rotation is enormous; it's nearly the same amount of energy that the sun radiates in ALL directions over the course of nearly two minutes. That's the equivalent of over a trillion hydrogen bombs. It would have to be a HELL of a monkey wrench to stop that big of a freight train. And even if the core DID stop spinning, where would all that angular momentum go? It would have to go into the rest of the Earth. Either the outer core would have to grab on to the inner (solid metal) core to slow itself down, which would make the inner core start rotating super-duper-fast (riiiiiight), or the outer core would have to grab onto the surrounding mantle (rocky) layers and get THEM spinning. And since the mantle of the Earth is a solid, getting it spinning faster would drag the whole rest of the planet along with it. Why didn't the characters in the movie notice that the days were getting shorter?

*) As a side effect of the screwiness of the Earth's magnetic field, huge numbers of birds suddenly lose all common sense and start crashing into things haphazardly. This is blamed on the fact that their long-range navigation is tuned to the Earth's magnetic field. Um, guys? Birds rely solely on their eyesight for avoiding flying into things. Messing up their navigation centers might cause them to migrate in the wrong direction, but it's not going to cause an Alfred-Hitchcock-like mass dive-bombing attack of crazed birds like we saw in this movie.

*) To start the core spinning again, our heroes are going to have to travel down to the Earth's outer core and detonate some multimegaton nuclear bombs. (Not a trillion of them, unfortunately — just five.) How this would jump-start the rotation of the outer core is left as an exercise to the viewer, although there were some pretty two-dimensional fluid-dynamics pictures of the shock waves the bombs would produce. Maybe the nuclear explosions would startle the hamsters that run on their little hamster-wheels and keep the Earth's outer core spinning normally, or something.

*) To make the trip down to the core, a lone brilliant researcher (just like the ones that infest Godzilla movies) has perfected a laser that can bore a wide hole through solid rock at 60 miles per hour. That's all fine and good, but how will they survive the tremendous temperatures and pressures inside the Earth? Answer: The same lone brilliant researcher has also perfected a supermetal of mythological proportions, which can stand up to anything except getting scraped really hard by a big diamond. The name he gives to this wonder metal is ... I'm not making this up ... UNOBTAINIUM. Groan. Among science fiction and fantasy writers, "unobtainium" has been used for decades as their coffee-clatch catch-phrase for metals that posess properties unobtainable in the real world. The mithril and adamant in Tolkien's Middle Earth, the arenak and dagal and inoson in E.E. "Doc" Smith's Skylark series, the biphase carbide of Steve Jackson Games' Ogre and GEV, adamantium and vibranium in Marvel comics, the Plasteel 1000 plating the talking car in Knight Rider — all of these would be referred to as "unobtainium" when the stories were discussed among science fiction and fantasy authors. But NONE of them would ever THINK to actually CALL their own wondermetal "unobtainium" in one of their stories! That would be too much like breaking the fourth wall. What they call unobtainium in this movie is not only capable of withstanding 9000 degrees of heat (Fahrenheit, Celsius, or Kelvin, the moviemakers didn't say), and of making a working hull that can stay intact with 800,000 pounds per square inch of pressure outside and only 14.7 pounds per square inch of pressure inside, it ALSO gets stronger the more pressure it's subjected to! (Just like the Incredible Hulk, I suppose. Maybe they should have called this metal "Bruce Bannerium.")

*) Using these two breakthroughs combined with another researcher's experimental X-ray vision device and 15 billion top secret U.S. government dollars (how does the government hide 15 billion dollars?), the lone brilliant researcher builds an Earth drilling ship, which he dubs "the Virgil." It looks like a short freight train. The crew compartment inside the Virgil is designed to rotate, to stay level if the Virgil is tilted up to 45 degrees away from the horizontal. Huh? You're going to be drilling down to the Earth's core. Why design your ship to work best when it's horizontal? Won't it be pointing straight down for most of the journey?

*) When our heroes (which include the luscious Hilary Swank, NOT dressed up like a boy this time) embark on their mission, we discover WHY the cabin is designed to pivot around the horizontal rather than around the vertical. They DON'T enter the Earth's crust going straight down. They enter at roughly a 45 degree angle. And they STAY at a 45 to 60 degree angle for most of the trip. Guys: If you do that, you're going to be SPIRALLING inward toward the core. Why not take the direct route? You'll have a lot less rock and metal and magma to tunnel through.

*) After a few of our heroes die violent and tragic deaths, the remaining heroes discover that the five 20-megaton nuclear weapons (pronounced "nuke-you-lar" by one of the characters) they have on board will not quite be strong enough to start the core spinning again. The last bomb needs to have a 30 percent larger warhead yield. How do our heroes increase the warhead's strength while they're down there at the Earth's core with no supply lines? Why, they borrow 67 pounds of plutonium from the Virgil's nuclear reactor and wire it to the last bomb's detonator, that's how! GAH! Okay, guys repeat after me:

ONE - The kind of plutonium they use in nuclear bombs is called "weapons grade" plutonium. It's the purest grade of plutonium-239 available. The kind of plutonium they use in a nuclear reactor is a much lower grade, and is incapable of sustaining the kind of quick runaway chain reaction necessary for a nuclear explosion.

TWO - A nuclear device with a huge warhead yield like 20 megatons does not use the nuclear fission of plutonium to generate most of its explosive force. It uses the nuclear FUSION of hydrogen isotopes. The tiny amount of plutonium it does use is merely a thermal "trigger", to get the hydrogen isotopes hot enough to undergo nuclear fusion. Adding more plutonium will not help you there. Now, there ARE special (and very "dirty") high-yield fission-fusion-fission bombs, which generate a large amount of extra energy by plating the fusion core with Uranium-238. The neutrons darting out of the fusion reaction will cause the surrounding uranium to fission, thus tripling or even quadrupling the total warhead yield. Non-weapons-grade plutonium may or may not work as a substitute. But:

THREE - You can't just set a reactor fuel cylinder full of plutonium next to a nuclear bomb, attach a detonating wire to it, and expect it to "go off"! The plutonium in a fission bomb has to be precisely placed in specially shaped explosive charges. The uranium-238 in a fission-fusion-fission bomb has to surround the weapon's fusion core. It's sloppy science like this that makes your average yokel afraid of nuclear power reactors because he thinks they can explode in a mushroom cloud at any time.

*) Now that the plutonium has been taken out of the reactor, the Virgil no longer has electric power. What do our two remaining heroes use for power so that they can escape? Why, they use a violation of the second law of thermodynamics! Remember how "unobtainium" is supposed to get stronger the more pressure its under? Well, somehow, our hero interprets this to mean that unobtainium can turn heat, such as the heat outside their hull, into useful energy. He welds the ship's electric wires onto a few points on the hull, and voila, the ship's electrical power is restored! Now, realistically, there is a known phenomenon called the piezoelectric effect which causes some materials to emit a weak electric current when they are compressed. The problem is, once you've compressed them, they STOP emitting electric current until you compress them HARDER. Subjecting them to a CONSTANT pressure — such as the steady high pressure outside the ship's hull — does nothing. But it's the HEAT, not the pressure, that our geophysicist hero says they're using as a power source. That's just baloney: No known process in the universe can convert heat into useful energy without a temperature DIFFERENCE. Every theoretical "heat engine" requires something not-as-hot to use as a kind of heat sink in order to generate energy. (If they used the inside of their cabin to facilitate this temperature difference, the cabin temperature would climb to the roasting point in seconds.)

*) The jury-rigged "hull-driven" power system can provide power for the Virgil's impellers, but not for its tunnel-drilling superlaser. In order to survive the trip back up from the outer (molten) core to the Earth's surface, the ship will have to remain in some kind of liquid the whole time. Yet, they have to travel through 2000 miles of mantle. In real life, as I've mentioned above, the Earth's mantle is solid. (Although molten lava is just really hot rocks, and the mantle is even hotter than molten lava in most places, the mantle is also under a tremendous amount of pressure, which keeps it solid.) In this movie's fantasy version of the Earth's interior, though, the mantle is one big mass of liquidy goo.

*) In an early part of the movie, while the Virgil was descending through the Pacific ocean, the sounds it made were shown to attract humpback whales. Fair enough. After it emerges from the Earth's crust at the bottom of the sea, however, these same sounds attract orcas ("killer" whales) instead. I guess the writers believe that all species of whales speak exactly the same language, or something.

Overall, the movie was kinda fun — if you don't know anything about geophysics, or thermodynamics, or radioactive materials, or computer network security, or ornithology, or basic physics, or any of the other disciplines you might have gotten exposed to in high school.

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