Film Review: 'The Core' – Scientific Review

Film Review: Sci-Fi • Disaster (2003)
'The Core'
Written by Joé McKen on Saturday, March 07, 2009

Major Rebecca Childs (Hilary Swank) learns there are some obstacles you just can't beat (though not many) in Jon Amiel’s 2003 The Core.

(NOTE – This is a special review that I’ve divided in two parts: the actual film review, detailing and reviewing the film itself, the characters, plot, etc.; and the scientific aspects of the film, detailing what’s acceptable and what’s just ludicrous to the point of hysterical laughter. I’ve made a separate page for each section.)

Section II/II: Scientific Review of The Core

SPOILER WARNING – This section is a full description of much of the film's more important points, so if you don't want some things to be spoiled for you, read no further!

This is a scientific dissection of the film and it's ups and downs, so if you don't bother to read moderately long texts or don't really care for science, this isn't for you. Also, I'll only detail the minimum, so if you don't understand something you're welcome to do your own research. Wikipedia's always a good place to start. ;) Much if the information in this section is a combination of my own findings, and mostly what I learned from Astronomer Phil Plait's own wonderful scientific dissection of The Core over at his site/blog, BadAstronomy.com.

This film contains both adequate and acceptable bits of science, and other (more) bits that just seem rather off-putting in terms of accuracy, so in that spirit I've separated this dissection into three parts: the Good, the Uncertain, and the Bad.

Color-code key:
Green = Entirely/mostly accurate and acceptable
Blue = Borderline accurate/false (has some truth and some inaccuracy to it)
Red = False & inaccurate

The Good

Earth's moving molten iron outer core can change and lead to the collapse, temporary or permanent, of the electromagnetic field
The film states that the Earth's outer liquid spinning core can change or stop in one way or another, which could trigger the Earth's EM field to collapse, either temporarily or permanently.

• This is actually (mostly) true, and in fact, the Earth's magnetic poles (which are of course governed by the EM field) have actually suddenly reversed several times in the planet's history. This is not well understood, and it seems to happen every few hundred thousand years or so.

• Note that life still exists on Earth though, so obviously cosmic radiation didn't kill the Earth's life systems during any of these 'frequent' reversals.

• In fact, this scenario is a large part of the popular 'Doomsday 2012' hype that states the end of the world will occur at the Winter Solstice of 2012 (December 21, 2012, to be precise). One of the more popular scenarios is another sudden pole reversal; in fact, this is founded in scientific fact, as many scientists do indeed estimate that a polar reversal could quite possibly occur in that timeframe. Considering we don't yet know the true effects of pole reversals, this could be either ineffective, or catastrophic (though not an extinction-level event).

Current deepest hole ever dug was 7 miles deep
In the movie, Dr. Keys argues against the idea of travelling to the Earth's core, saying the deepest humans had ever gotten through the crust was about seven miles, with a two-inch drill bit.

• I don't know about the 'two-inch drill bit', but the seven miles bit is entirely accurate. He's undoubtedly referring to the Kola Superdeep Borehole, a Russian project that was to dig the deepest hole they could (I can't find any website listing their potential motivations for doing so).

Using a peach as a model of the Earth's interior design
In his explanation of how bad the Earth's electromagnetic field disintegrating would be for the Earth and anything on it, Dr. Keys illustrates the Earth's interior with a peach he cuts in half: the skin is the crust, the meat is the mantle, and the pit is the core.

• This is actually a very accurate representation of the Earth's interior compared to scale. The skin is about as thick as the crust would be for an Earth that size, and so is the mantle, and the core (the outer core in this case). (Not sure the Earth would be as tasty, though.)

The Uncertain

Space Shuttle rotation
In an early scene, we see a NASA Space Shuttle in orbit quickly flip rightside-up from upside-down relative to the Earth with its little jets, in about 10 seconds.

• The jets ('reaction control systems') aren't that powerful in real life, and it takes quite a while longer for a Space Shuttle to flip a whole 180 degrees, somewhere in the range of between 20 seconds and nearly two minutes.

• However, this is a movie with an audience after all, so it's understandable that even if the writers knew this, they could've just sped it up somewhat so we don't spend over a minute slowly watching the Space Shuttle right itself.

Earth's collapsing electromagnetic field opens door to deadly cosmic rays
As the Earth's electromagnetic field slowly but surely becomes unstable and eventually collapses, deadly cosmic rays will reach the Earth and kill everyone.

• 'Cosmic rays' is a very general term used to designate everything that's whizzing around in Space, from protons (light) to helium (mostly-harmless gas). Most of these are actually quite inoffensive to humans and the Earth and probably wouldn't even be noticed should they hit.

• There are some cosmic rays that are actually dangerous or lethal to life, but even without the electromagnetic field, most would be stopped by the Earth's atmosphere, resulting in low damage, if any.

• There are, however, extremely powerful Gamma Ray bursts that occasionally go off in Space, shooting horrendously massive amounts of cosmic rays that would completely wipe away the Earth's electromagnetic field and part of its atmosphere, and, indeed, kill much of life on Earth, depending on the proximity to the Gamma Ray blast. This scenario is suspected of being responsible for one of Earth's largest-ever mass extinctions, the Ordovician-Silurian extinction event. Thankfully, these are extremely rare, as demonstrated that only one has ever hit the Earth in the planet's existence, so it's safe to assume we won't have to worry about another one anytime soon.

Earth's spinning molten iron outer core moves at '1,000 miles per hour'
The film states that the Earth's spinning molten iron outer core rotates at about '1,000 miles per hour'.

• No, it's slower by about half. It's actually estimated at about 550 mph, considering it takes about 24 for the mass to do a full rotation across the outer core's roughly 2,200-mile-wide radius.

• It's possible the line was just used as a hyperbole meaning 'high speed', such as when one would say 'I broke the sound barrier getting here!' to mean they just drove really fast.

Super-suits that can withstand the mantle's heat and pressure inside a geode
The Terranauts' suits can withstand the incredible pressures (estimated in the film as roughly 800,000 pounds per square inch) and temperatures (roughly 5,000 degrees, in the film), yet still allow the crew a fair amount of agility and flexibility.

• Of course, realistically this is simply ludicrous. Any suit built to withstand those sorts of pressures and temperatures would a) be impossible with today's materials and technology, and b) even if they were built, they'd be incredibly tough and thick with insulation, rendering flexibility virtually nonexistent. You'd be in a sarcophagus. Conversely, any suit allowing you to bend and move would be too thin to provide any sort of insulation or protection against the heat or pressures.

• But of course, this is Sci-Fi, and naturally we had to see the Terranauts get out of the ship at least once or twice while they're inside the Earth, so of course some leniency can be expected.

A gigantic geode deep in the Earth's mantle
Deep in the mantle, the crew fall into a gigantic geode, thousands of feet across.

• How could such a large empty space survive, or even form to begin with, in a place as extreme as the mantle?

• HOWEVER, the writer of The Core himself states that scientists have once found a mile-long geode in the shallow depths of the mantle, which, if true, would certainly prove this as possible and imply that perhaps even larger geodes could be possible. However, there are no other links or mentions of this find anywhere else I could find, so one should perhaps take this statement with a grain of salt until it's confirmed. Read this interview here. (Warning: lots of explicit language that may offend certain folks.)

Bodies float on magma
In the geode scene, when Commander Iverson is killed by a falling rock through his helmet, he falls into the magma and is sinks into it.

• The human body is roughly the same density as water, whereas magma, being molten rock, is roughly the same density as, well, rock. Rock being denser than water, Iverson's body should've floated on top of the magma instead of sinking into it, like a cork would float in water while a rock would sink. Density matters.

• However, it was possible that Iverson's body actually burned and melted away by the magma, in which case what we see isn't actually the body sinking into the molten rock, but burning away until there's nothing left. It's hard/impossible to tell which for now, so I'm labelling this as 'uncertain'.

How the Golden Gate collapsed after melting under a microwave beam
In the movie, a sudden ray of microwave radiation hits San Francisco through a hole in the Earth's EM shield, cutting right across the Golden Gate Bridge's central span, melting the deck and the cables until it collapses, the towers leading into the span.

• This contradicts how a suspension bridge actually works. The cables and their supporting pylons are continually under an immense amount of load-bearing stress as they carry the entire weight of the deck below. If the deck suddenly collapses and the supporting cables suddenly snapped, the cables would violently recoil outwards, towards the shores where they're anchored at, which would pull at the towers to bend towards the shores instead of into the gap. Imagine you playing Tug-o'-War against a tree. If the rope suddenly snapped, would you be sent flying towards the tree, or in the direction you were pulling?

• However, it's possible the destroyed bridge shot was meant to imply that the towers themselves had also partially melted and weakened, causing them to lean in one direction or another without just snapping off.

Multiple bombs would create a ripple effect in a single direction, pushing the outer core liquid to rotate again
The crew's 'Plan D^[1]' (long story) ends with them leaving behind five individual 250-megaton bombs (which, combined, formed the original 1,000-megaton bomb) which, detonated at precise intervals, would create a converging ripple effect through the core and restart the spinning motion.

• I'm no genius in physics, but this seems faulty to me. I'm marking this as 'uncertain' for now because I simply don't know if this could work and I don't really have a model of the core to test it on, but my guess would be it would just be like 5 cases of the original bomb: the ripples, even from 5 separate bombs, would just bleed away in all directions inconsequentially.

The Bad

Space Shuttle sonic boom
In the Space Shuttle off-course scene early in the movie, as the shuttle roars over a baseball match in downtown L.A., a sonic boom is heard.

• Sonic booms only occur when an object surpasses the speed of sound. That Shuttle was going much slower than Mach 1, so no sonic boom would've been heard.

Space Shuttle off-course
In the Space Shuttle scene early in the movie, a momentary glitch in the Shuttle's navigation and positioning systems (GPS on overdrive) result in the shuttle being off-course by 130 miles.

• There are numerous tracking methods employed to locate a Space Shuttle, far more than a single transponder on the Shuttle itself. If the glitch only occurred on the Shuttle to the Shuttle's systems but not to Ground Control, Ground Control should still have kept a location on the Shuttle quite accurately, and it would've never gone off-course.

Earth's molten iron outer core has stopped rotating
The cause for the movie's scenario of the Earth's EM field to start to collapse is that the Earth's outer core, which is a ball of molten iron the size of Mars spinning at 1,000 miles an hour, somehow stopped spinning, all of a sudden.

• This is simply impossible. The amount of energy held in such a vast moving body as the outer core is equal to roughly five trillion megaton nuclear bombs. Logically, it would require the energy of five trillion nuclear bombs to stop the core completely in its tracks – and probably five more trillion bombs to start it all moving again as before.

• Also, even if it did happen, all that energy would have to go somewhere (basic physics: energy never 'disappears', it just goes elsewhere, changes form). If the core suddenly stopped spinning, the 5 trillion megatons of energy would logically go into the Earth's crust, likely obliterating it into shreds, vaporizing all the oceans on Earth ten times over, etc. Cosmic radiation would be the very least of our problems.

Earth's electromagnetic field is created by a spinning molten iron outer core
The movie states that the Earth's EM field is created as a result of the liquid outer core spinning in one direction at roughly equal and constant velocity all over.

• Yes, magnetism is caused by moving charges. In that sense, a spinning ball of molten iron the size of Mars would indeed create a massive electromagnetic field, but that's not how it's done in Earth's case.

• The Earth's outer core isn't spinning in a single direction; it's actually extremely complicated, with currents and counter-currents of ionized iron and other materials all interacting together to create Earth's EM field. It's less like a fluid highway, more like Rush Hour in Mexico City with cars zipping everywhere in 'controlled chaos'.

• If the writers had tried to be more accurate, they could've simply imagined a scenario where these currents had somehow been destabilized greatly, causing the imminent disruption and collapse of the EM field. This would've been far more plausible.

Earth's electromagnetic field shields us from deadly microwave radiation
In the film, even worse than cosmic rays would be microwave radiation, which would literally 'cook' the planet, killing all life and destroying the atmosphere for good.

• Microwaves aren't actually dangerous at all; they're basically light. In extremely concentrated doses they can cause damage (such as sticking one's hand in a microwave like a friggin' idiot), but microwave radiation from the Sun or from space is extremely diluted and low-intensity, as it makes up very little of the Sun's output. Even if all microwave radiation in nearby Space were to hit us, we'd likely never even notice.

• Also, the Earth's electromagnetic field, being electric and magnetic, only affects rays and matter made from charged particles. Microwaves have absolutely no charge, so they aren't even slowed down by the EM field. It's as though it weren't even there.

A single 1,000-megaton nuclear bomb could push the outer core liquid in one direction and start it spinning again
The original plan was to detonate a single thousand-megaton nuclear bomb in the outer core, which would give just enough push to start the core rotating again in one direction.

• This is utterly ridiculous. Anyone who's ever thrown a rock into a swimming pool knows the water didn't suddenly start rotating in one direction, but that the ripples went out in all directions at equal speed. No single/simple impact, bomb or otherwise, could made a liquid spin in a single direction without sending equally-powerful counter-shockwaves in all other directions. This would just create ripples an waves in the outer core (not necessarily a good thing) and that's it.

• Even if it was possible to push a liquid in a circular container to move in one direction, how could they possibly choose which way the bomb would result in the liquid turning?

Virgil's emergency compartment ejection mechanism
The Virgil is designed so that if a compartment is damaged, it can be automatically jettisoned via an emergency ejection mechanism, preventing damage to the remaining compartments, 'sorta like the keys on a key-ring'.

• This seems very poorly thought-out to me. Okay, so a compartment is damaged. Who's to say it would always be the last compartment? If a central compartment was damaged and was ejected, seeing as the ship is essentially a long cigar tube, any other compartments behind it would also be ejected, damaged or not. They would lose the entire ship for one single compartment being ejected, so this seems like a huge shortsighted error.

The Coliseum (and other structures) explodes after being supercharged by lightening
When Rome is hit by a supercharged lightening storm, the Coliseum is rapidly hit by many jolts of lightening until it 'overcharges' and finally explodes violently into rubble.

• The writer himself admitted, in the interview posted earlier, that this was just for the sake of special effects, and that a more realistic result would be the structure cracking and shattering and merely crumbling instead of actually exploding. Same goes for all those other buidings and statues shown exploding in this scene.

After being punctured, the geode slowly fills with magma
When the Virgil broke through the massive geode's protective cobalt cocoon, the exterior magma slowly opened a relatively small hole through which magma simply poured, slowly filling the geode.

• I very highly doubt the plausibility of this. If they'd punctured an opening large enough for that sort of flow, the integrity of the entire cocoon would've been compromised and it would've all just completely shattered and disappeared under the immense pressures of the mantle magma outside. Same thing as striking a small hole in a window: instead of a small hole, the whole thing cracks and weakens, and eventually shatters.

• Of course, one can understand this was done simply for time restraints; the characters needed enough time to start the ship so they could escape.

Virgil crew communicating with Mission Control through mantle and crust
Throughout much of their subterannean adventure, the Virgil crew are able to communicate with Mission Control on the surface with crystal clarity in transmission and reception.

• Again, this is just Hollywood distorting what in reality would be simply impossible for the sake of the movie's needs. Characters need to communicatem, after all.

The Virgil emerging at Hawaii between two tectonic plates
After finally restarting the core, the Virgil makes it out through an opening between two tectonic plates somewhere near Hawaii.

• Basic geography: Hawaii is located in the center of a tectonic oceanic plate, over a thousand miles away from any faultlines. Its volcanoes are caused by a constant mantle plume, a giant magmatic pocket of sorts that spawns and feeds the islands' volcanoes. There is no way the Virgil could've made it through miles of solid crust rock without its lasers, unless it somehow found a magma chamber and got 'erupted' out of a volcano, which wasn't the case.

• Incorrectly regarded as a goof: many criticize the Virgil making it through the mantle and crust without its lasers functioning (it was running on limited power after Dr. Keys had rigged the ship to be powered solely from its Unobtanium shell). Again in the interview linked previously, the writer explains the ship actually followed magmatic flows through the crust, which were more intense than previously due to the core suddenly spinning again. They just 'went with the flow', thereby not requiring their lasers.

---

If anyone finds a problem with the movie I forgot to mention or didn't find myself, or if something I 'corrected' here is actually wrong, do let me know, will you? Thanks. :)

Return to Part I/II: Film review of The Core

Edit – thanks to Aimee for a quick correction.

^{* * * * *
[1] Plan A: use the single 1,000-megaton bomb to restart the core (failed). Plan B: trigger Destiny (Deep Earth Seismic Trigger Initiative – DESTINI) to try and restart the core's spinning (sabotaged by 'Rat' the cracker). Plan C: 'Restart the core somehow' = using the multiple-bomb scenario. Plan D: same as C, but sabotaging Virgil's emergency ejection mechanisms to eject individual compartments with the bombs in them (success!).}