00:00We know more about space than we do about the ocean.
00:05We know more about the ocean than we do about the Earth's core.
00:11But how do we study something that lies more than a thousand miles beneath our feet?
00:16All the enough, you need to fly into space.
00:19Thanks to satellites orbiting the planet, scientists have discovered something strange at the very heart of the planet.
00:26News about mysterious signals from space barely surprises anyone.
00:31But how about this?
00:33We detected strange signals coming from deep beneath our own home.
00:38Before we go into those signals, we need to understand why it's so important to study what's inside the planet.
00:45How does the core affect us?
00:47Our lives depend on it in several crucial ways.
00:51First, the core plays a fundamental role in gravity.
00:54We don't drift off into space because a massive spherical mass of molten metal locks us to the surface.
01:02Second, it powers Earth's magnetic field.
01:06Dangerous cosmic radiation and solar wind that could scorch everything are blocked thanks to the planet's magnetic field.
01:14And third, the inner processes of the Earth influence earthquakes and volcanic eruptions.
01:20Any disturbance inside the core and mantle can change life on the planet.
01:24And recently, scientists recorded something unusual coming from down there.
01:30At the beginning of this century, the United States and Germany launched a mission called GRACE, the Gravity Recovery and Climate Experiment.
01:39At first, this project used two satellites to track how water moved around the planet and how glaciers were melting.
01:47But the satellites could also measure Earth's gravitational field.
01:51If gravity was slightly stronger or weaker in some region, one of the satellites would be pulled toward that spot, and the other would measure the change in distance.
02:01In very simple terms, the heavier something is, the stronger its gravitational pull.
02:07In certain parts of the planet, gravity can be slightly higher because of large geological shifts, ocean currents, or melting ice.
02:15But between 2006 and 2008, the GRACE satellites detected a strange change in gravity along the coast of Africa.
02:25Melting ice, water movement, and other natural phenomena couldn't explain the anomaly.
02:31No one knew what it was at the time.
02:32But years later, scientists suggested that the nature of this signal was coming from the Earth's core.
02:40Researchers noticed that some minerals, like perovskite, can undergo a phase transition when exposed to enormous pressure and extreme heat.
02:49And there are many perovskites lying in the upper layers of the mantle.
02:55When the internal structure of this mineral reshapes, it becomes denser and shifts the surrounding rocks.
03:01Deep underground, this harder, solid part moves the softer, molten rock.
03:06These movements reach the molten outer core and slightly deform it.
03:11This deformation inside the core alters the flow of molten iron.
03:15And this deep current of liquid metal directly affects Earth's magnetic field.
03:21That's why satellites recorded those fluctuations.
03:25So how does all of this affect us?
03:28We launch satellites, we use compasses, we rely on GPS.
03:33All of this works only because gravity and the magnetic field are stable.
03:38And both depend on the core.
03:40That's why it's so important to study the Earth's heart.
03:45And to do that, we don't need to dig thousands of miles.
03:49Movements on the surface can reveal what is happening inside.
03:55Studying vibrations in the crust, recording gravitational shifts, calculating, modeling, and forming hypotheses.
04:03It all sounds a little boring.
04:05Is there another way to figure out what's happening down there?
04:07We sent voyagers into space, and some of them have already left the solar system.
04:14We descend into the depths of the Mariana Trench inside bathyskifs.
04:18So what's the problem with drilling a shaft deep into the Earth's crust?
04:23Humanity actually has some experience with this.
04:27In the 1970s, Soviet geologists began drilling the Kola Supra Deep borehole.
04:32It became, and remains, the deepest artificial borehole ever created.
04:38Its depth reaches 7.6 miles, deeper than the Mariana Trench and higher than Mount Everest.
04:45More than 50 years have passed, and humanity has not gone deeper than 7.6 miles.
04:51And do you know where the Earth's core begins?
04:55At about 1,800 miles down.
04:58That's almost 7 times farther than the distance to the International Space Station.
05:03To reach the core, we would need to drill a hole 230 times deeper than the Kola Supra Deep.
05:09But that project was shut down in 1992, and the borehole was closed in 2005.
05:15What stopped us from digging deeper?
05:18First, the density of the rock.
05:21In the early stages, the drill easily cut through granite.
05:24But around 4.3 miles down, the rock became much harder.
05:29The drill broke several times.
05:31Workers had to change the drilling direction to pass through softer layers.
05:35Eventually, the borehole shape looked like a string of lights hanging on a Christmas tree.
05:41Another problem was heat.
05:42The deeper the engineers went, the hotter it became.
05:46Scientists expected that past a depth of 10,000 feet, the temperature would be around 212 degrees Fahrenheit.
05:53In reality, the harder they worked, the worse it got.
05:57Eventually, it reached 356 degrees Fahrenheit.
06:02The hottest place on Earth is the Sonoran Desert along the Mexican-U.S. border.
06:08Temperatures there can reach 177 degrees Fahrenheit.
06:11That's twice as cool as inside that terrifying borehole.
06:17And the challenges did not stop there.
06:19At a depth of about 14,800 feet, the rock became porous.
06:24The extreme heat gave it a strange plasticity.
06:27Instead of solid stone, the drill had to cut through something more like hot, softened material that was almost impossible to drill.
06:35On top of that, the stability of the shaft became a danger.
06:40At such depths, the walls could collapse at any moment.
06:43To drill deeper, humanity would need completely new technology.
06:47A drill capable of working at 500 degrees Fahrenheit.
06:52That is the temperature scientists expect in the upper mantle, located just beneath the crust.
06:57And to reach it, we would need to drill 25 miles down.
07:02Almost three times deeper than the Kola Superdeep.
07:04There are many rumors about what the engineers supposedly discovered in that hole.
07:10The most popular claim is that they heard the screams of thousands of people who were stuck in the fiery underworld.
07:17Other fake stories claim that the workers went insane after seeing something horrific at the bottom.
07:23And that's why the project was stopped.
07:25But if we ignore these myths, what did scientists actually find?
07:30They learned that the existing temperature model of Earth's interior was wrong.
07:34It was far hotter down there than expected.
07:37Geologists thought they would find the so-called Conrad discontinuity.
07:41A transition from granite to basalt.
07:44They found no such boundary.
07:47The real discovery was a liquid at incredible depths.
07:50Scientists found cracks filled with briny water.
07:53This changed our understanding of the crust.
07:56People used to believe it was completely solid.
07:58But now it appears full of fractures and channels through which water can move.
08:03Where did it come from?
08:05Geologists think the fluid was squeezed out of the rocks by enormous pressure,
08:10as water is wrung out of a sponge.
08:12But the most astonishing discovery was...
08:15Life!
08:15At about 4.5 miles down, engineers found ancient fossils of single-celled marine organisms.
08:22They were nearly 2 billion years old, and they had survived at such extreme heat and pressure.
08:29Let's imagine that one day we actually reached the mantle.
08:32What would that give us?
08:34What would we expect to see?
08:36We would finally understand how Earth formed billions of years ago,
08:40how the core, mantle, and crust developed, and how plate tectonics works.
08:46We'd know how the plates push and pull against each other.
08:49We'd gain a deeper understanding of earthquakes.
08:52Researchers also hope to find extremophiles.
08:55These are primitive organisms that can withstand extreme heat and pressure.
09:01If we discover life near the mantle or even within it,
09:04scientists will study it closely and try to understand how it manages to survive under such brutal conditions.
09:11If we learn what keeps life alive in the most hostile environment beneath our feet,
09:17we might learn how to protect life in other extreme places,
09:21from the depths of the ocean to distant planets.
09:23Studying the heart of our planet could reveal technologies we can barely imagine today.
09:29Our future might depend on the mysteries hidden beneath our own world.
09:37That's it for today.
09:38So hey, if you pacified your curiosity, then give the video a like and share it with your friends.
09:43Or if you want more, just click on these videos and stay on the bright side.
