15 Astonishing Facts About the Earth's Core
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00:00Deep beneath the Earth's surface lies a mysterious world of molten metal and immense forces that
00:06shape our planet.
00:07In today's video, I'm counting down 15 of the most astonishing facts about the Earth's
00:11core.
00:12Let's start with number 15.
00:14Magnetic Reversals The Earth's magnetic field acts like an invisible
00:18shield that keeps us safe from harmful cosmic rays from space.
00:22This field doesn't stay the same.
00:24Every few hundred thousand years, it flips, switching the north and south poles.
00:29This flip, while not entirely understood, is closely linked to what happens deep inside
00:33the Earth's core.
00:34Here's how it works.
00:35Deep beneath the Earth's surface, about 1,800 miles down, is the outer core made of
00:40molten iron and other metals.
00:42This liquid layer surrounds a solid inner core.
00:45The movement of these metals generates electric currents, which in turn creates this magnetic
00:49field.
00:50It's this field that makes a compass point north.
00:54Over time, the movement of the metal in the outer core can get a bit messy and chaotic.
00:59This chaos can cause the magnetic field to flip completely, a change that happens irregularly
01:04and it's hard to predict.
01:06The last time this happened was about 773,000 years ago, in what is known as the Matuyama-Brunnhez
01:12Reversal.
01:13Recent studies have shown that this reversal took about 22,000 years to complete, much
01:17longer than the 4,000 to 9,000 years scientists originally thought.
01:21This suggests that the flipping process is more complicated and takes more tries than
01:25previously believed.
01:27Although scientists are still trying to figure out exactly why and how these reversals happened,
01:31they know that during a reversal, the magnetic field weakens significantly.
01:36This weakened field doesn't protect us as well from cosmic rays, which could increase
01:40radiation on the Earth's surface and cause problems with satellite communications and
01:44power grids.
01:45The full impact of these changes on life on Earth is still a topic of debate, but understanding
01:50these magnetic reversals is critical, as they could have significant effects on our technology-reliant
01:56world.
01:5714.
01:59The Age of the Core Not all parts of the Earth are created equal.
02:04It's made of many parts, some older than others, with the core being the granddaddy of them
02:09all.
02:10Scientific studies have placed the age of this inner core at around 1 to 1.3 billion
02:14years old, making it one of the oldest parts of our planet.
02:18But how is it possible for the core to be so ancient, and how do scientists determine
02:21that age?
02:23Studying the age of the core not only reveals the history of our planet, but also offers
02:27insight into the origins of life itself.
02:30The Earth's core is a solid ball of iron, surrounded by a liquid outer core that slowly
02:34churns, generating the planet's magnetic field.
02:38The reason the core is so ancient lies in its formation process.
02:42As the Earth cooled over billions of years, the molten iron at its center began to solidify,
02:46forming the inner core.
02:48This process started around a billion years ago, long after the planet itself had formed.
02:53As the planet loses heat to space, the cooling starts from the inside out, causing the core
02:58to crystallize first.
03:00This means that while the surface of the Earth continues to evolve and change, the core has
03:04remained relatively unchanged for billions of years.
03:08Determining the age of the Earth's core isn't easy.
03:11Scientists can't dig down there, so they rely on indirect methods.
03:14By creating the immense pressure and temperature found deep within the Earth in lab settings,
03:19scientists can estimate when the core began to solidify.
03:22Recent experiments involve squeezing iron between two diamond anvils and heating it
03:27with lasers, creating conditions similar to those in the core.
03:30These studies show that the iron in the core conducts heat at a certain rate, which helps
03:34scientists estimate when the inner core started to form.
03:38The results suggest that the core is around 1 to 1.3 billion years old, placing it in
03:42the middle range of previous estimates.
03:4513.
03:47It's Mushy For decades, the Earth's inner core was believed
03:51to be a solid ball of iron, dense and unyielding, surrounded by a swirling, liquid outer core.
03:58But recent research has flipped that notion on its head, revealing that the core is not
04:02as solid as we once thought.
04:04Instead, it turns out that the Earth's core is a strange mix of hard, semi-soft, and even
04:09mushy iron.
04:11But how can something buried so deep beneath our feet be anything but solid rock?
04:14Well, the Earth's inner core, sitting at more than 3,000 miles beneath the surface, has
04:18long been imagined as a tightly packed sphere of iron.
04:22After all, iron is heavy and solid at room temperature, so it made sense to assume that
04:26under the extreme pressures and temperatures found in the Earth's core, it would be even
04:30denser and harder.
04:31However, new studies suggest that the core is a bit more complex, with regions that are
04:36not only soft, but also semi-soft, and even partially molten.
04:40This softness at the core can be compared to a thick, sludgy material, solid enough
04:45to resist flow in some areas, but soft and squishy in others.
04:49This unusual consistency is the result of extreme conditions at the core, where temperatures
04:53will reach over 9,000 degrees Fahrenheit, and pressures are more than three million
04:57times that of the Earth's surface.
04:59So given that we can't physically reach the Earth's core, scientists rely on indirect
05:03methods to study it.
05:04The most powerful tool at their disposal?
05:06The analysis of seismic waves generated by earthquakes.
05:11Seismic waves come in two main types, compressional and shear waves.
05:14When large earthquakes happen, these waves travel through the Earth and can be detected
05:17on the opposite side of the planet.
05:19By comparing the speed and path of these waves as they travel through the core, scientists
05:23noticed something strange.
05:25The waves didn't behave as if they would if the core were entirely solid.
05:30Instead, the waves were deflected or slowed down in certain areas, suggesting that the
05:34core has softer regions, even mushy material.
05:3912.
05:40Iron and Nickel
05:42So when we think about the Earth's core, it's easy to picture it as a bubbling sea of lava,
05:47thanks to countless science fiction movies and books.
05:49But the reality is far more complex and fascinating.
05:53The Earth's core is divided into two parts, the outer and inner.
05:56While both predominantly are composed of iron and nickel, they exist in very different states.
06:00The outer core is about 1,400 miles thick and is made of molten iron and nickel.
06:05In this churning liquid outer core that generates the magnetic field through a process known
06:09as geodynamo, the inner core is a solid sphere with a radius of about 760 miles.
06:16Despite the extreme heat, though, comparable to the surface of the sun, the immense pressures
06:20at this depth forces the iron and nickel to remain in a solid state.
06:24The discovery of this inner core dates back to the 1930s, when scientists first noticed
06:28that seismic waves behaved differently than expected, leading to the conclusion that the
06:32Earth's core had a solid center.
06:35The core isn't just a fascinating geological feature, it's crucial for life on Earth.
06:40The movement of the molten outer core generates a protective magnetic field that shields our
06:44planet from harmful solar radiation.
06:47The solidification of the inner core also plays a vital role in that process.
06:51As the inner core grows, it releases heat, which drives convection currents in the outer
06:55core, powering the geodynamo and maintaining the magnetic field.
07:0011.
07:02Under Pressure While it's easier to imagine the Earth's
07:06core as a flow of liquid hot magma, it's actually a place of unimaginable pressure
07:11and heat, where conditions are so extreme that they could easily crush or vaporize anything
07:17from the surface.
07:19The core is a solid ball of crystallized iron, roughly the size of the moon, surrounded by
07:24a molten outer core.
07:26Despite being hotter than the surface of the sun, the intense pressure keeps the iron in
07:30the core solid.
07:32But what exactly happens under these extreme conditions and how would that affect the human
07:36body if it were possible to venture there?
07:39The pressure at the Earth's core is about 3.5 million times higher than what we experience
07:44here at the surface.
07:46To put that into perspective, the weight of an entire atmosphere pressing down on us is
07:50only about 14.7 pounds per square inch.
07:54At the core, the pressure is around 52 million and a half pounds per square inch.
08:00This pressure is beyond anything we can truly imagine.
08:04While the iron on the surface has a relatively simple crystal structure, deep in the Earth's
08:07core, the atoms are forced into a much denser arrangement.
08:11If you were somehow transported to the Earth's core, the outcome would be immediate and devastating.
08:18Forget about the heat, the pressure would crush you instantly.
08:21The human body, which is mostly made up of water and soft tissues, would have no chance
08:26of withstanding such forces.
08:28Every cell in your body would be compressed into a fraction of its size, and you would
08:33be reduced into a dense mass almost instantaneously.
08:39But beyond the pressure, the temperature at the core is around 10,000 degrees Fahrenheit,
08:43hotter than the surface of the sun.
08:45Even if you could somehow survive the pressure, the heat would turn a human into gas and then
08:49evaporate them in a matter of faster than Thanos can snap his fingers.
08:53The iron at the core remains solid only because the pressure is so great that it prevents
08:57the atoms from moving freely and turning into a liquid.
09:0110.
09:02Hotter Than The Sun As I've already mentioned, the Earth's core
09:06reaches staggering temperatures.
09:08Astonishingly, the Earth's core is hotter than the surface of the sun, a fact that changes
09:13our understanding about what lies beneath our feet.
09:16These temperatures go up to around 10,800 degrees Fahrenheit.
09:20Now to put that in perspective, the surface of the sun is about 9,930 degrees Fahrenheit.
09:25This means that the Earth's core is around 870 degrees hotter than the surface of the
09:29sun.
09:30So, we'll start from the beginning.
09:32When the Earth was formed around four and a half billion years ago, it was a molten
09:36mass of rock and metal.
09:38The process of this formation involved countless collisions and mergers of planetesimals, small
09:43celestial bodies, which generated an enormous amount of heat.
09:47The core is also heated by the decay of radioactive isotopes like Uranium-238, Thorium-232, and
09:53even Potassium-40.
09:55These elements release heat as they break down, a process that continues over billions
09:59of years, maintaining the high temperature.
10:02The heat from the core plays a critical role in shaping our planet.
10:05It drives the movement of tectonic plates, which float on the semi-fluid mantle above
10:09the core.
10:10This movement causes earthquakes, volcanic eruptions, and the creation of mountain ranges,
10:15all of which have a profound impact on the surface.
10:18As heat from the core radiates upwards, it causes convection currents in the mantle.
10:23These currents are slowly moving the plates of the Earth's crust, a process known as plate
10:26tectonics.
10:28Without this heat-driven movement, the Earth would be a static, lifeless planet, and that
10:33wouldn't be very fun, now would it?
10:35While the Earth's core has remained hot for billions of years, it is slowly cooling.
10:39However, this process happens over such an extended timescale that it's virtually imperceptible
10:44in human terms.
10:45The core cools by about 100 degrees Celsius every billion years, meaning it could take
10:50another billion years for it to cool by any significant amount.
10:54The Earth's core has been cooling since the planet's formation, and while radioactive
10:57decay continues to generate heat, it's not enough to increase the core's temperature
11:01over time.
11:039.
11:05Hollow Earth?
11:07The Hollow Earth theory is one of those tantalizing ideas, despite its clear contradictions with
11:13established science, and has managed to captivate the imagination for centuries.
11:18At its core, no pun intended, the theory posits that our planet is not a solid sphere, but
11:23rather a hollow shell with vast empty spaces or even entire civilizations existing beneath
11:29the surface.
11:30While the idea is intriguing and has inspired countless works of fiction, it ultimately
11:34falls apart under the weight of modern scientific understanding.
11:38From ancient times, the notion of a world beneath our feet has held a powerful allure.
11:43From the ancient Greeks, the underworld was a realm of the dead, a dark and mysterious
11:47place that existed beneath the crust.
11:50These early concepts were largely metaphorical, representing the afterlife or place of myth
11:54rather than a physical reality.
11:56However, in the 17th century, the Hollow Earth theory began to take on a more scientific
12:01guise, gaining traction among some of the leading thinkers of the time.
12:05One of the earliest scientific proponents of the Hollow Earth theory was that of Edmund
12:09Halley, the astronomer best known for Halley's Comet.
12:12In 1692, Halley proposed a radical idea to explain certain anomalies in compass readings.
12:18He suggested that the Earth was composed of a series of nested spherical shells, all revolving
12:23around a central core.
12:25While Halley's theory was imaginative, it was also based on fundamental misunderstandings
12:29of the Earth's structure, a misunderstanding that has since been thoroughly debunked.
12:34In the end, the Hollow Earth theory is a fascinating example of how human curiosity and creativity
12:40can lead to fun, if not misguided ideas.
12:43While it is kind of fun to imagine a world within our world, populated by mysterious
12:47beings or even advanced societies, the Earth is in fact anything but hollow.
12:538.
12:54The Gutenberg Discontinuity Deep beneath the Earth's surface lies a boundary
13:00that has intrigued scientists for over a century, the Gutenberg discontinuity.
13:05This is a remarkable discovery made by German seismologist Benno Gutenberg in 1913, and
13:10it's greatly enhanced our understanding of the Earth's interior and the dynamic processes
13:14that shape our planet.
13:16Yet despite its significance, this boundary still holds many mysteries.
13:20The Gutenberg discontinuity is a transition zone located approximately 1,800 miles beneath
13:26the Earth's surface, where the solid lower mantle meets the liquid outer core.
13:31This boundary isn't a single sharp line, but rather an uneven, narrow zone that varies
13:35in depth and structure.
13:37It represents a profound change in the Earth's internal composition and marks the point at
13:42which seismic waves, vibrations generated by earthquakes, behave very differently.
13:47Gutenberg, born in 1889, was a pioneering seismologist who dedicated his career to studying
13:52the Earth's inner layers.
13:54In 1913, he made a groundbreaking observation.
13:57At a certain depth beneath the surface, the behavior of seismic waves changed dramatically.
14:03Primary waves, which can travel through both solid and liquid, slowed down significantly,
14:08while secondary waves, which can travel only through solid material, disappeared entirely.
14:13This observation led Gutenberg to the conclusion that at around 1,800 miles deep, the Earth
14:17transitions from a solid state to a liquid one.
14:21This established the boundary now known as the Gutenberg discontinuity.
14:25This boundary has helped scientists to better understand the structure of the Earth, including
14:29the existence of the outer core, which is composed of molten iron and nickel.
14:34Despite its importance, though, the Gutenberg discontinuity does remain shrouded in mystery.
14:39One of the key questions that scientists continue to explore is how this boundary changes.
14:44The intense heat within the Earth causes the core to gradually cool and solidify, which
14:48could lead to changes in the position and characteristics of this discontinuity zone.
14:54Moving on to number seven, olivine.
14:57In the layers beneath the giant onion that we call the Earth, a mineral called olivine
15:03plays a critical role in unlocking the mysteries of the planet's interior.
15:08Found deep within the Earth, often in the mantle, olivine is a silicate material that
15:12provides scientists with essential clues about the composition and history of the Earth's
15:17layers, particularly those below the crust.
15:20Olivine is a magnesium-iron silicate with a distinctive greenish hue, ranging from olive
15:25to emerald green, which is where it derives its name.
15:29The presence of olivine is particularly prominent in peridotite, a rock that dominates the upper
15:34mantle.
15:35This mineral is not only abundant in the subsurface, but also found in meteorites, offering a small
15:39glimpse into the building blocks of the solar system.
15:43Olivine is most commonly found in the Earth's mantle, which lies between the crust and the
15:47core.
15:48While the mantle is typically inaccessible due to its depths, olivine can be brought
15:52closer to the surface through volcanic eruptions or tectonic activity.
15:56Additionally, oceanic drilling projects have allowed scientists to retrieve samples of
16:00olivine from beneath the seabed, particularly in regions where the Earth's crust is thin.
16:05Accessing olivine-rich mantle rocks ain't easy.
16:08Most of the Earth's mantle lies tens of miles beneath the surface, far, far out of reach
16:12of conventional drilling.
16:14However, in places where tectonic plates diverge, such as the Mid-Atlantic Ridge, the mantle
16:18can be exposed or brought closer to the surface.
16:21This was the case with the Atlantis Massif, where a scientific expedition managed to drill
16:25deeper into the Earth's mantle than ever before, retrieving a nearly intact core of olivine-rich
16:30rock.
16:31This monumental achievement has provided scientists with invaluable data and samples for studying
16:36the Earth's internal processes.
16:396.
16:41Life Comes From The Crust The origins of life on Earth are inextricably
16:46linked to the planet's crust, a connection that reveals the profound impact of geological
16:50processes on biological evolution.
16:53This seemingly simple layer of rock beneath their feet has played a critical role in nurturing
16:58the early conditions that allowed life to flourish, shaping the trajectory of biological
17:03complexity over billions of years.
17:06The Earth's crust, the outermost solid shell of our planet, is more than just a foundation
17:11for life, it is the birthplace of life itself.
17:14This concept suggests that the earliest forms of life may have emerged from the unique environments
17:19created by the crust, particularly in hydrothermal systems and other geothermal hotspots.
17:25The Earth's crust is composed of a rich variety of minerals and elements, many of which are
17:29essential for life.
17:30When combined with water, these minerals can undergo chemical reactions that produce the
17:35building blocks of life, such as amino acids and other organic molecules.
17:40These reactions are intense in hydrothermal systems, where heat from the Earth's interior
17:44interacts with the water and minerals in the crust.
17:46Four billion years ago, the Earth was a pretty violent place, frequently bombarded by asteroids
17:52and comets.
17:53These impacts were not only reshaping the planet's surface, but they also contributed
17:56to the foundation of vast hydrothermal systems.
17:59These systems were likely widespread and may have been some of the earliest habitats of
18:03life.
18:04The high temperatures and rich chemical environments in these systems would have been ideal for
18:08the formation of simple, heat-loving organisms known as thermophiles.
18:13The process of life's emergence from the Earth's crust was gradual and complex.
18:18Initially, the heat from asteroid impacts and volcanic activity created a hostile environment,
18:23but as the planet cooled, the conditions became more favorable.
18:27In the deep ocean ridges, where the crust is thinner and the mantle closer to the surface,
18:31tectonic activity created mid-ocean ridges and hydrothermal vents.
18:35These vents released hot, mineral-rich water into the ocean, providing the perfect environment
18:39for life to begin.
18:425.
18:44Is It Leaking?
18:46Recent discoveries have revealed that the core is not as isolated as once thought.
18:51It's leaking.
18:52This leakage has profound implications for our understanding of the planet's internal
18:56dynamics and its long-term evolution.
18:59When scientists say that the Earth's core is leaking, they're referring to the slow
19:03transfer of materials, particularly certain elements, from the core into the mantle, the
19:08layer of thick rock surrounding the core.
19:10This process has been happening for billions of years, but it's only recently that we've
19:14gathered enough evidence to confirm it.
19:17The leak primarily involves elements like tungsten, which is found in different isotopic
19:21forms.
19:22By studying the ratios of these isotopes in volcanic rocks, researchers have been able
19:26to trace the movement of tungsten from the core into the mantle.
19:30So we've talked a lot about the iron core today, but there are some more elements within
19:34the core, tungsten, platinum, and gold, all of which are known to dissolve in iron-nickel
19:39alloys.
19:40The leak involves the migration of these elements, particularly tungsten, from the core into
19:44the mantle.
19:45This leak suggests that the Earth's core and mantle are more interconnected than previously
19:50thought, with materials slowly moving between these two layers over geological timescales.
19:55The leak of materials from the core to the mantle is thought to be driven by two main
19:59processes.
20:00The first of which is the mantle plume.
20:03These are upwellings of hot rock that rise from the core-mantle boundary to the Earth's
20:07surface.
20:08As the plumes ascend, they bring core material with them, including tungsten.
20:12Mantle plumes are responsible for creating volcanic hotspots, like those in Hawaii and
20:16Iceland, where this core-derived material can sometimes be found in the rocks.
20:21The next process is called subduction and oxygen increase.
20:24Here, the tectonic plate boundaries, the slabs of Earth's crust that are pushed down into
20:29the mantle, in a process known as subduction.
20:31These slabs carry oxygen-rich materials into the deep mantle.
20:35Our experiments suggest that increasing oxygen concentrations at the core-mantle boundary
20:40can cause tungsten to separate from the core and migrate into the mantle.
20:45Well, the core has been leaking for at least two and a half billion years, according to
20:48studies of tungsten isotopes in ancient rocks, but before this period, during the first 1.8
20:53billion years of the Earth's history, there seems to have been little or no transfer of
20:57material from the core to the mantle.
20:59This suggests that the Earth's interior dynamics have changed significantly over time, with
21:04the onset of more vigorous mantle convection and tectonic activity potentially triggering
21:09the leakage.
21:104.
21:12The Kola Superdeep Borehole Those who are old enough to remember may recall
21:16the space race between the US and the USSR, but we don't often hear about the inner space
21:22race.
21:23With 1% probes like Voyager 1 billions of miles beyond our solar system, our attempts
21:27to penetrate the Earth have barely scratched the surface.
21:31The Kola Superdeep Borehole, located on Russia's Kola Peninsula, represents the deepest point
21:37ever reached by human drilling, extending 7.5 miles down into the Earth.
21:41Now, despite this impressive depth, it only penetrates about a third of the way through
21:46the continental crust and a mere 0.2% of the Earth's total radius of almost 4,000 miles.
21:53The project was part of a less-publicized Cold War race between the US and the USSR,
21:58where the two superpowers sought to explore the Earth's depths in a bid to outdo each
22:02other in scientific achievements.
22:03While the US abandoned its efforts with the Project Moho due to funding issues, the Soviet
22:09Union persisted, eventually creating the Superdeep Borehole.
22:12Despite this, the borehole remains just a tiny dent in the Earth's layers, a reminder
22:17of how much remains unknown.
22:20This borehole revealed unexpected conditions as scientists ventured deeper.
22:24At depths of around 33,000 feet, temperatures soared to over 356 degrees Fahrenheit, much
22:31higher than the 212 degrees that scientists had predicted.
22:34These extreme temperatures, combined with increasing rock porosity, transformed the
22:38rock into a plastic-like state, making further drilling nearly impossible.
22:44One of the most remarkable findings, though, was the discovery of microscopic fossils in
22:48rocks over 2 billion years old.
22:51These fossils, encased in organic compounds, survived under immense pressure and heat,
22:56offering direct evidence of ancient life deep within the Earth's crust.
23:00This finding was not only unexpected, but also raised new questions about the history
23:04of life on our planet and the conditions in which it can persist.
23:093.
23:11The Mantle Is Recycling Oceanic Crust Kurtall Recycling is a process that's been
23:17going on beneath our feet for billions of years.
23:19It's basically the Earth's way of renewing its crust, like how we recycle materials to
23:25make new things.
23:26Scientists recently found out that this recycling happens much faster than we initially thought,
23:31about half a billion years instead of the 2 billion years previously believed.
23:35Kurtall Recycling refers to the process where the parts of the Earth's crust that are
23:39pushed deep down into the mantle later reappear at the surface.
23:43In regions like the Pacific, the crust of the Earth's crust has a conveyor belt.
23:45Sections of it get dragged down, melted, mixed with mantle minerals, and eventually resurface.
23:50This process has been happening for as long as the Earth has had tectonic plates.
23:55But thanks to some new research, we know it can happen much faster than we thought.
23:59Scientists figured this out by studying volcanic rocks from Mauna Loa in Hawaii, the largest
24:03volcano on Earth.
24:05By examining specific elements like strontium isotopes in these rocks, they were able to
24:09track how old the material is and where it came from.
24:12In regions like the Pacific Oceans, ring of fire, earthquakes, and volcanic eruptions
24:16are common, and they're the direct evidence of the ongoing recycling process.
24:20But what's surprising is that this whole cycle, from surface to mantle and back, can take
24:25as little as 500 million years.
24:27Forces push and pull the plates around, causing some to dive down into the mantle, and once
24:32there the crust material heats up, melts, and mixes with it.
24:35Eventually, the material finds its way back up to the surface, usually through volcanic
24:39eruptions.
24:40This process helps keep the Earth's surface dynamic and constantly changing.
24:44It also plays a big role in the planet's ability to regulate its temperature and recycle
24:48essential materials like water and minerals.
24:50They're crucial for life.
24:532.
24:54Core Collapse The Core Collapse Theory is an idea that gets
24:58thrown around in discussions about Earth's future, and it might sound like something
25:02out of a science fiction movie.
25:04But what does it actually mean?
25:06Has Earth's core ever collapsed?
25:08Is it even possible?
25:09Well, Core Collapse Theory suggests that the Earth's core, the solid and liquid iron-nickel
25:13center of our planet, could fail or collapse in some catastrophic way.
25:18This could happen if the processes that generate Earth's magnetic field were to stop working
25:22correctly.
25:23The magnetic field is essential, and acts like a shield protecting us from harmful solar
25:27radiation.
25:28But, no, the Earth's core has never fully collapsed.
25:31However, scientists have discovered that Earth's magnetic field, which is generated by the motion
25:35of molten iron in the outer core, has almost collapsed before.
25:40About 591 million years ago, the magnetic field weakened dramatically and it nearly
25:46failed.
25:47This was a close call, but instead of collapsing, Earth's core managed to stabilize and strengthen,
25:52likely due to the solidification of the inner core.
25:55While a full collapse of Earth's core is unlikely, the weakening of the magnetic field
25:59is not only plausible, but has happened in the past.
26:02The field's strength fluctuates over time due to changes in the flow of the molten iron
26:06in the outer core, and those fluctuations, if they were extreme enough, could lead to
26:10a significant weakening of the field.
26:12However, a total collapse of the core, as in a scenario where the core stops functioning
26:17altogether, is highly improbable given our current understanding of Earth's geodynamics.
26:22If Earth's core were to collapse, or even stop generating a magnetic field, we would
26:27see some dramatic effects.
26:29The most immediate impact would be the loss of our magnetic field, which would expose
26:33the Earth to intense solar radiation.
26:35Without it, the Earth's atmosphere would gradually erode, potentially leading to a loss of water
26:40and other essential gases.
26:42The loss of this field could also affect the Earth's climate, potentially causing more
26:46extreme weather patterns and shifts in temperature.
26:49These changes would make the Earth a much more hostile place for life, possibly leading
26:53to a mass extinction, similar to events that happened during the past geomagnetic reversals.
26:591.
27:01Its Changing Rotation The Earth's core is often viewed as a stable,
27:07unchanging part of our planet, but recent research suggests it might be more dynamic
27:12than we previously thought.
27:14Scientists have found that the Earth's inner core, a solid sphere of iron and nickel, may
27:18be changing the direction of its rotation.
27:21The Earth's inner core rotates within the outer core.
27:24This rotation happens because the Earth itself is spinning, and the inner core is somewhat
27:28decoupled from the rest of the planet due to the fluid outer core surrounding it.
27:33Normally, the inner core rotates slightly faster than the Earth's surface, a phenomenon
27:37known as superrotation.
27:39This rotation isn't perfectly synchronized with the mantle and crust due to the different
27:43physical properties and the dynamic environment of the core.
27:47Researchers analyzed seismic waves from earthquakes, which traveled through the core to detect
27:51changes in its rotation over time, and they found that while the core was spinning faster
27:55than the Earth's surface from the 1970s to the 2000s, it began to slow down around
28:002009.
28:01Now, it might be rotating more slowly than the rest of the planet.
28:04This change in rotation isn't dramatic, it's measured in tiny fractions of a degree
28:08per year, but it's significant enough to be detected by sensitive seismic instruments.
28:13The idea that the inner core's rotation might change over time isn't entirely new.
28:18Some scientists have hypothesized that the core's rotation could oscillate, changing
28:22direction every few decades or so.
28:24However, this is still a topic of debate, with different studies suggesting varying
28:28rates and patterns of rotation.
28:30For example, while some researchers have proposed that the core could shift its rotation direction
28:34every six years or so, others believe that the core might rotate at a consistent rate,
28:39with occasional lurches or shifts.
28:41In any case, the potential change in the core's rotation is intriguing, but it doesn't pose
28:46any immediate threat to life on Earth.
28:48The core's rotation, though, could influence the planet's magnetic field, which protects
28:52us from harmful solar radiation.
28:55One possible effect of the core's slowed rotation is a slight alteration in the length
28:59of Earth's days.
29:00If the inner core continues to decelerate, though, it might cause the Earth's rotation
29:04to slow down as well, leading to slightly longer days.
29:08This change would be minuscule, on the order of milliseconds over many years, so it's not
29:13really something we are ever going to notice.
29:16Thanks for watching, everyone.
29:17I'll see you next time.