What If You Drill Through The Earth? | Unveiled - video Dailymotion

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00:00 Earth's underground environments are a mostly unknown world.

00:03 There are thousands of complex cave systems, full of strange creatures that never see the

00:07 light of day, with some leading so far down that no human has yet explored them.

00:12 But at these absolute extremes, if we did explore them, then how far could we really

00:17 go?

00:18 This is Unveiled, and today we're answering the extraordinary question; what happens if

00:23 you drill through the Earth?

00:26 Do you need the big questions answered?

00:28 Are you constantly curious?

00:29 Then why not subscribe to Unveiled for more clips like this one?

00:32 And ring the bell for more thought-provoking content!

00:36 First off, what is Earth actually made of?

00:38 At its simplest, it consists of crust, either oceanic or continental, with sections known

00:43 as tectonic plates covering the entire surface.

00:46 The crust is then always made of rock, but of different kinds of rocks in different places

00:50 and at different layers.

00:52 Below this topmost layer, there's the mantle, which is Earth's magma source.

00:56 And then, finally, we have the core, both the inner and outer.

01:00 The core is a thousand miles down, incredibly dense, and billions of years old.

01:05 Here, at the heart of our planet, it's made of super-hot, super-dense iron and nickel,

01:10 and temperatures can be more than 10,000 degrees Fahrenheit.

01:14 We know, then, that inside the Earth isn't exactly a welcoming place… but nevertheless,

01:19 humans are still intrigued by all that's below us.

01:23 Theories about the Earth perhaps being hollow and hosting unknown ecosystems have appeared

01:27 in science fiction for a long time, and although the hollow Earth theory doesn't actually

01:32 hold up, there certainly are strange and genuine underground realms that are intriguing, even

01:38 bewitching.

01:39 The deepest known natural cave on Earth is Virovkina Cave in Eastern Europe.

01:43 At about ten miles long and more than 7,000 feet deep, it's an extreme and unique environment.

01:49 If it were an ocean instead of a cave, its depth would put it firmly in what's known

01:53 as the "Bathypelagic Zone", with pressure hundreds of times greater than what's found

01:57 at the surface.

01:59 Unfortunately, and perhaps unsurprisingly, some explorers have died inside Virovkina

02:03 Cave.

02:04 Ultimately, though, it's very likely that Virovkina is even deeper than we currently

02:08 know, and also that there are other, far deeper cave systems out there that haven't even

02:13 been discovered yet.

02:15 What really puts the scale of the Earth into perspective, however, is that in all cases

02:19 we are still a long way away from reaching down into even Earth's second layer, the

02:23 mantle… let alone further still, to the core and out the other side.

02:28 Do man-made caves offer any improvement?

02:30 To some degree, yes.

02:32 Virovkina Cave is about 1.3 miles deep, but the deepest mine in the world, the Mpana Gold

02:38 Mine in South Africa, is almost double that, reaching 2.5 miles.

02:42 If we abandon "traversable" underground systems - i.e. if we look at the deepest locations

02:47 but ones that humans can't travel down into - then we come to what's truly the deepest

02:52 man-made hole in the world, the Kola Superdeep Borehole in Russia.

02:57 It is more than 7.6 miles deep, and is a real benchmark in the field, given that it was

03:02 a drilling project conceived solely to see how deep it was possible to drill into the

03:07 Earth's crust.

03:08 Thankfully, the borehole is only about nine inches wide and is now sealed off, so there's

03:13 no danger of anybody falling into it.

03:15 But even if you did, you'd still - and again - be way off how deep you'd need to go to

03:20 reach the core, or to emerge out the other side.

03:23 There's simply nothing on Earth, currently, that takes us even close.

03:27 The middle of the core is about 4,000 miles below the surface, meaning we'd need to

03:32 dig an 8,000-mile tunnel to punch through to the other side of our planet.

03:37 The longest still-in-use tunnel in general - going across the Earth and not down into

03:41 it - is the Delaware Aqueduct in the US, but it is only about 85 miles long.

03:46 We'd need, then, almost 100 times more.

03:49 And it would all have to withstand untold pressure and temperature.

03:53 In reality, drilling through the Earth - as simple as it sounds - isn't something that's

03:57 yet technologically possible for humanity.

04:00 But say that money is no object, some kind of tech solution is discovered, and that the

04:05 entirety of our species has, for some reason, decided that we really, really need to create

04:10 this passage.

04:11 What then?

04:12 First, we'd need a material not only to build the tunnel out of, but also our drilling

04:17 apparatus.

04:18 Again, that material would need to be capable of withstanding extreme temperatures and depth.

04:23 There are those highs of around 10,000 degrees Fahrenheit, while the pressure would top out

04:27 at about 3.6 million atmospheres.

04:30 For context, the deepest known point in the ocean, Challenger Deep in the Marianas Trench,

04:35 has about 1,000 atmospheres of pressure.

04:37 Even it just isn't comparable.

04:39 When thinking of material that could work, you might immediately go to diamond, which

04:43 can cope with up to five times as much for the pressure.

04:46 However, the melting point of diamond is a paltry 7,200 degrees Fahrenheit, so it would

04:52 inevitably melt partway through our journey.

04:55 Which is a shame, because a diamond drill for a diamond tunnel seems like it would be

04:59 a pretty cool thing.

05:01 Scientists have researched this specific problem, however, and before come up with a new material

05:06 that combines hafnium, nitrogen and carbon (hafnium being a lesser-known transition metal).

05:12 But even this fares only slightly better than diamond, with a melting point of 7,460 degrees.

05:19 Even our most thoroughly researched custom materials, then, only get us to the edge of

05:24 the Earth's core.

05:25 And, of course, only in theory.

05:27 Staging any kind of practical test for what we'd need - some kind of new wonder metal

05:32 or element - is basically impossible.

05:35 But hypothetically, say we do have such a material, what other obstacles would our Earth-splitting

05:40 tunnel face?

05:41 The consistency - or rather inconsistency - of Earth is another problem.

05:45 Drilling through rock is one thing, and in fact is the only thing we know… but eventually

05:50 you get to the mantle, full of heavy, molten lava.

05:52 So, in carving our tunnel we would need a craft that can drill through the ground, yes,

05:57 but it would then need to become the most extreme submarine ever, capable of wading

06:01 through magma.

06:03 And then it would need all of those temperature and pressure resistance qualities in order

06:07 to survive the core.

06:09 Anything that could do all of that would be some machine.

06:12 But, hypothetically, say we do have such a machine.

06:16 Next we'd have severe navigation problems, since there would be literally zero visibility

06:21 for the very vast majority of our mission.

06:23 And then the heat remains a major issue, even with an indestructible, hypothetical wonder

06:28 material.

06:29 Because just because something won't melt when subjected to thousands of degrees, doesn't

06:33 mean it won't get so hot inside that humans can't survive.

06:37 The conditions on the inside of our tunnel through Earth would be hellish.

06:41 More than that, they would boil you alive.

06:43 So, here's hoping we develop some ultra-advanced climate control systems, as well.

06:48 But maybe we have all of that, too.

06:50 We've got our tunnel made from an impossible material, the incredible machine needed to

06:54 actually build it, some super-advanced air conditioning, and some sort of vehicle that

06:58 can withstand the entire journey.

07:00 How long would the journey take?

07:02 Again, we have 8,000 miles to traverse.

07:05 The fastest train in the world is currently the Shanghai Maglev in China, which travels

07:10 at 286 miles per hour.

07:12 At that constant speed, we're talking nearly 28 hours to tunnel through the planet, which

07:16 is longer than it would take to just fly between the two points on an airplane.

07:20 But here's where one final and crucial consideration comes into play.

07:24 Because when drilling through the Earth, we're actually not beholden by how fast trains,

07:28 or anything, can move on the surface.

07:30 The force of gravity messes all that up.

07:32 As it's pulling everything directly towards the core all the time, we know that the journey

07:36 to the centre of the Earth would, in reality, be much shorter.

07:39 It would potentially take less than an hour.

07:42 However, there's a catch.

07:43 And a big one.

07:44 Because with gravity pulling you in, how can you ever hope to get away?

07:48 Your journey from the centre of the Earth - the second half, in terms of plane distance

07:52 - just isn't going to happen.

07:54 Unless you manage to conduct the entire journey also in a total vacuum, then no matter what

07:58 you do, gravity will always mean that it's actually impossible for you to leave.

08:02 So, even if you've managed to build a tunnel to withstand the pressure - which means you

08:07 haven't been crushed - you'd still find yourself hopelessly cast adrift, trapped in

08:11 a tomb of your own making, waiting to starve and eventually die.

08:15 Which isn't really the ending we were hoping for.

08:18 But what do you think?

08:19 Would digging a tunnel through the Earth be worthwhile?

08:21 Or would it just be completely absurd?

08:24 Even if it were possible.

08:25 For now, the want to explore is usually to be applauded… but sometimes, even the most

08:29 fundamental laws of physics are telling you that it's probably a bad idea.

08:34 And that's what would happen if you drilled through the Earth.

08:38 What do you think?

08:39 Is there anything we missed?

08:40 Let us know in the comments, check out these other clips from Unveiled, and make sure you

08:44 subscribe and ring the bell for our latest content.

What If You Drill Through The Earth? | Unveiled

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