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Delve into the fascinating dynamics of Earth's evolving crust and how a drastic shift in the planet's land-water ratio could reshape everything. These thought-provoking scenarios explore the potential for a new era on our planet.
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00:00Ever wondered what Earth would look like if it was split evenly between land and water?
00:05I mean like 50% land and 50% ocean, like a cosmic pizza with just two toppings split equally.
00:14First things first, we all know that water is essential for life.
00:19That's why scientists search for water on other planets to find potential life.
00:23On our own planet, water covers about 71% of its surface, with most of it found in the oceans.
00:31What if we took away almost a quarter of that water and replaced it with land?
00:37If we did balance out the land-to-water ratio, we would see some pretty drastic changes.
00:42Due to the sea level drop, regions around the north and south poles would dry up completely.
00:48Meanwhile, every continent on the planet would expand to reveal an enormous amount of new territory.
00:56This would be equivalent to the current surface areas of Asia, Europe, Africa, and North America combined.
01:04Imagine all those new vacation spots you could explore with all that land.
01:09This shift in the ratio of land and water wouldn't be all sunshine and rainbows though.
01:15With much less water covering the surface, our ocean currents would get messed up, leading to a destabilized climate.
01:23This would mean colder temperatures around the poles and even hotter temperatures in the already scorching equatorial regions.
01:31Rain levels would drop, creating dangerous droughts and new deserts in many inland areas.
01:38Let's not forget about the creatures living on Earth.
01:42Plants, animals, and humans would all need to adapt to being less dependent on water.
01:48Some animals may even evolve to be smaller or switch to a strictly carnivorous diet due to water scarcity.
01:56And sadly, lots of life forms in our current oceans would struggle to survive,
02:01which would be a huge bummer for all the fish lovers out there.
02:06Let's try to imagine a totally different scenario for our planet next.
02:11Back in 1884, the press reported on an astronomer who claimed to have discovered a cubic planet beyond Neptune.
02:20We've sure come a long way since then.
02:22We've come to know that in our universe, there's no possibility of planets being square,
02:28at least based on the information we have today.
02:32Let's travel back in time to 4.5 billion years ago when our own planet was just a hot mess
02:38of gas and dust.
02:40As this chaotic cloud collapsed, a hot star formed and began to attract all nearby matter with its gravitational pull.
02:49Eventually, a rotating disk formed around the star,
02:53and collisions between particles led to the formation of massive bodies, planets.
02:59And because gravity pulls equally from all sides towards the center,
03:04planets naturally take a spherical shape.
03:07But what if we spice things up and skew the distribution of gravity?
03:12Well, if you're feeling adventurous and want to live life on the edge,
03:16then welcome to the cube Earth.
03:18Yay! We'd have six sides now, but don't get too excited.
03:23None of them would be any fun.
03:25You'd constantly feel like you're climbing up a steep hill, no matter where you go.
03:30That's because gravity is strongest at the center of each face.
03:34So the further away you were from the center, the stronger pull you'd feel.
03:39Say goodbye to taking standing tall for granted.
03:43If you found yourself on the edges of the cube Earth, you'd find no lush and vibrant landscapes.
03:49All the water would pool at the center of each face, leaving the edges rocky and barren.
03:55And forget about breathing easily.
03:58The atmosphere along the edges and corners would be too thin or non-existent to support life.
04:05But we'll come back to that later.
04:08The climate on the cube Earth would depend on how it would rotate.
04:12If it spun on an axis through two faces, then the climate would be similar to what we have on
04:18Earth now, but more extreme.
04:21The top and bottom faces would be polar, while the other four would enjoy an equatorial climate.
04:27However, if the cube Earth rotated through its corners,
04:31each side would have a climate with more moderate temperatures and precipitation.
04:35Say goodbye to extreme weather, but also wave goodbye to your equatorial paradise.
04:42On the bright side, you would probably be able to walk into outer space.
04:48Since the atmosphere is held down by gravity, and gravity would now be pulling towards the center of each face,
04:56the atmosphere would be thicker there and thinner towards the edges.
05:00If the cubic Earth had the same volume as our round world today,
05:04its sharp corners would poke out beyond our atmosphere, creating unprotected and uninhabitable areas.
05:11But who says you wouldn't be able to rent a spacesuit and stand on top of the world and outside
05:17of it at the same time?
05:19Talk about taking your vacation to new heights.
05:22How about if our planet was completely covered with water?
05:27Well, it turns out that ancient Earth might have been just that, a water world.
05:32According to some researchers, our planet was mostly covered with oceans about 3 billion years ago,
05:39with only a few scattered islands popping up here and there.
05:44The scientists who made this discovery have been studying rock samples found in Western Australia.
05:51By analyzing these rocks, they were able to determine that they formed in a hydrothermal vent system on the seafloor
05:58over 3 billion years ago.
06:00This information could have some major implications for how we understand the origin and evolution of life.
06:08See, scientists still have a lot of questions about where Earth's water came from and when it appeared.
06:15But by studying these ancient rocks, they're hoping to get some answers.
06:20One way they're doing this is by looking at the oxygen found in the rocks.
06:26You see, water with different values of oxygen can tell us a lot about the environment in which it formed.
06:33And the researchers found that the rocks from 3 billion years ago had heavier oxygen content than we see in
06:40our modern oceans.
06:42This suggests that at that time, dry land hadn't emerged yet, which means that Earth was mostly covered in water.
06:51Now, this might not seem like a big deal, but it could actually help us understand how life first formed
06:58on Earth.
06:59If our planet was completely covered with water when the first single-celled organism emerged, then they probably didn't form
07:07on land.
07:08And if that's the case, it could mean that other water-covered planets might be ideal places to search for
07:15life.
07:16Our planet may never be fully covered in water ever again, but we might end up losing some, if not
07:23all, of our planet's hydration.
07:26Here's the deal. The sun is going to get hotter over the next few hundred million years.
07:32This isn't anything to do with humans and our shenanigans.
07:35It's just a natural thing that happens with all stars.
07:38The bad news is that the sun gets hotter, our planet is going to heat up too.
07:43And if things get really toasty, we're going to start losing our oceans to evaporation.
07:50Sure, we've got plenty of time to hit the beach before that happens.
07:54Experts have been working hard on a super fancy computer model to predict exactly when all this is going to
08:01go down.
08:02And according to them, we've got around one billion years until things get seriously steamy.
08:09You might be wondering how they came up with that number.
08:12It turns out that when the sun gets hotter, it makes the atmosphere warmer too.
08:17And as the atmosphere warms up, more and more water evaporates from the oceans.
08:23There's a catch though.
08:24Water vapor is actually a greenhouse gas, which means it traps heat and makes things even hotter down there on
08:31the surface.
08:31As we lose more and more water, we're going to end up in a loop where the planet just keeps
08:37getting hotter and hotter until there's no water left at all.
08:41But hey, it's not all about us.
08:44This research could actually help us find other planets with liquid water.
08:48By figuring out what kinds of conditions are needed to keep water on a planet, we might be able to
08:54identify some other hospitable worlds out there.
08:57And who knows, maybe in a billion years, we'll have colonized one of those planets.
09:03It's been there for over 3 billion years.
09:06But now, some of the Earth's oldest crust is falling apart.
09:11Today, our continents seem stuck in place.
09:13But over a long, long time, they've moved and shifted around a lot.
09:18It's all thanks to tectonic activity, which makes part of Earth's surface slowly slide around like pieces of a giant
09:25puzzle.
09:26Some of the most stable parts of these puzzle pieces are called cretons.
09:31Cretons are super old and strong sections of rock that form the roots of continents and keep them together.
09:37The North American cretin is one of them.
09:39It makes up a big part of the United States, about half of Canada, and most of Greenland.
09:46Scientists have singled out about 35 of these big ancient cretons around the world.
09:51They mostly stayed in the same place for hundreds of millions of years because of how strong they are.
09:57But in 2014, they discovered that cretons might not be as indestructible as they thought.
10:03Some cretons had lost parts of their strong roots because of certain geologic processes and became thinner.
10:10It looks like cretons could become less stable if they go through more tectonic changes.
10:16In 2024, scientists at China University of Geosciences analyzed an ancient landmass called the North China Creton, or NCC for
10:26short.
10:27They wanted to learn more about how some of Earth's oldest rock regions can break apart.
10:32This process of cretons disintegrating is called decretonization.
10:36The NCC is so interesting to study because it has three main parts – the Western Bloc, the Eastern Bloc,
10:44and the trans-North China Orogen, a zone that lies between the two blocks.
10:49Scientists found that during the Mesozoic era, the Eastern Bloc lost its deep ancient roots because of the strong Earth
10:56movements called tectonomagmatic events.
10:59So scientists wanted to see exactly how the processes in the mantle and the movements of Earth's plates led to
11:05the breaking down of the NCC.
11:08They created 4D models showing how the NCC's shape changed over time, including its surface shape, how its layers stretched,
11:16and the way earthquake waves moved through it.
11:19They found that a section of the tectonic plate slid beneath the cretin and then began to roll back.
11:24This rolling and stretching made the strong rock thin out and eventually lose stability.
11:30All this started around 200 million years ago, back during the Jurassic period, when dinosaurs were rocking the world.
11:39The North China cretin isn't the only place where this decretonization process can happen.
11:44Other cretons, like those in North America, South America, and China's Yangtze region, may have gone through similar changes.
11:52Scientists say this shows how the continents on Earth have slowly changed and evolved over billions of years.
11:58And it looks like, when it comes to geology, there's no place that is 100% safe from changes.
12:04But it's no cause for alarm.
12:08You don't notice this, but our planet never stops moving and is perfectly normal.
12:13But sometimes, this movement still brings dramatic changes.
12:17In 2017, scientists made an official announcement that Zealandia can be called a new continent.
12:24The continental shelves of this mysterious continent are lying at a depth of around 3,280 feet below sea level.
12:32The nearest oceanic crust dives even deeper, at 9,800 feet below that.
12:39Geologists have gone deep down to collect rocks from the ocean floor.
12:42They've found that, unlike the nearby oceanic crust, which is made up of fresh basaltic rocks,
12:48the crust around New Zealand is a mix of ancient granite, limestone, and sandstone.
12:53All this screams continental crust.
12:56Plus, scientists have discovered a narrow strip of oceanic crust that separates Australia from the hidden land of Zealandia.
13:04It means these two are separate continents.
13:0685 million years ago, Zealandia decided to break free from the supercontinent Gondwana.
13:13Millions of years later, the mighty Pacific Plate, the heavyweight champion of tectonic plates,
13:19decided to take a dive beneath Zealandia's continental crust.
13:23And that's how the root of Zealandia, that connection to its continental crust, broke off and went into the depths
13:30below.
13:30And that's not all the tectonic news from this part of the world.
13:34120 million years ago, Australia and Antarctica were a single piece of land.
13:40They went there separate ways, but Antarctica didn't leave empty-handed.
13:45Today, there's an oceanic plateau in the Indian Ocean.
13:49Long ago, it was connected to another lost continent, the Kyrgyzian microcontinent.
13:54Scientists believe that it made a land bridge between India and Antarctica.
13:58To find out what it was like, we can look at a tiny archipelago in the southern Indian Ocean.
14:04These islands are all that is left of the ancient landmass.
14:08They have a cold climate and feature glaciers because they're so close to Antarctica.
14:13But in the past, the weather here must have been temperate with plenty of rainfall.
14:18The animals and plants would have been similar to those that live in tropical regions today.
14:23Another lost and found continent isn't hiding in the ocean, but under Europe.
14:28It's called Greater Adria, and it collided with Europe and started to sink under it around 100 million years ago.
14:36Today, it lies beneath Italy, Greece, and the Balkans.
14:39Its size and even shape match that of Greenland, the world's largest island.
14:44Greater Adria is no longer visible, but it left some clues.
14:48Part of it was embedded in the Alps.
14:51The other chunks are part of present-day Italy and Croatia, on the other side of the Adriatic Sea.
14:57Limestone rocks from the former continent started to change once they were under the European landmass.
15:04Great heat and pressure spread over tens of millions of years changed their structure.
15:09And that's when the limestone left the chat, and the marble took its place.
15:14Greater Adria wasn't a solid piece of land like the big continent we see today.
15:18But more like a giant shallow shelf underwater.
15:22Over time, sand, mud, and other stuff settled on this shelf and slowly turned into rock.
15:28Greater Adria might have been a little like Zealandia or the Florida Keys, a chain of small islands sitting in
15:35a shallow sea.
15:36Above the water, there were probably lots of little islands and archipelagos.
15:40And beneath the waves, there were colorful coral reefs filled with marine life.
15:45If you lived back then and had a scuba tank, it would have been an amazing place to dive and
15:50explore.
15:52So, with all the things going on with the Cratons, who knows?
15:56We could see a new continent in the future.
15:59Plus, studying the Earth's crust even deeper can change history as we know it.
16:04Scientists in Copenhagen have made an amazing discovery about the real birthplace of Scandinavia.
16:10And it's not where we thought.
16:12After studying sand and rock from remote parts of Finland, they found out that Scandinavia's roots actually came from Greenland
16:19over 3.75 billion years ago.
16:23This means the area where Nordic countries are now is 250 million years older than the scientists had previously believed.
16:31And we now know, thanks to the tiny crystals called zircons found in Finnish river sands.
16:37When scientists looked closely at their chemical makeup, they realized the age of crystals matched the rocks found in Greenland,
16:44not Scandinavia.
16:46They used special techniques to analyze elements like uranium, lead, luteum, and hafnium,
16:52and discovered that Scandinavia's rocky base most likely broke off from Greenland billions of years ago.
16:58A small seed of land probably started drifting across the Earth's surface over hundreds of millions of years.
17:05This piece eventually settled where Finland is today.
17:08Over time, new layers of rock formed around this seed and slowly turned into the Scandinavia we see on maps
17:15now.
17:17The same study could help us rethink how the continents on Earth first formed.
17:22The most accepted theory is that the continental crust began growing right when the planet was formed.
17:28But new studies show that the signs of continents only started growing a billion years later.
17:34The scientists explain that Earth's continents may have begun as tiny seeds of ancient crust in different places.
17:41These seeds grew over time, forming the landmass as we know today.
17:45These ancient seeds aren't just found in Scandinavia, but also in Australia, South Africa, and India.
17:52Scientists aren't sure if all these seeds came from the same place, or if they grew separately in different parts
17:58of the world.
17:59So there's still a lot to learn, and scientists need to keep digging to figure out if all these ancient
18:04seeds are related to each other.
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