Why Continents Haven’t Sunk Into Lava Yet

Bright Side

It’s wild to think about, but the continents haven’t sunk into lava because of how Earth’s crust works. The crust, which includes the continents, is like a giant jigsaw puzzle of solid plates floating on a gooey layer called the mantle. Even though the mantle is hot and partly molten, it’s dense enough to keep the crust floating instead of letting it sink. Plus, continents are made of lighter, less dense rock compared to the heavier ocean floors, so they naturally stay on top. Earth’s tectonic plates might shift and collide, but they’re surprisingly sturdy over millions of years. So, while there’s plenty of molten rock beneath us, the continents are safe from sinking anytime soon!  Credit: CC BY 4.0 https://creativecommons.org/licenses/by/4.0/: Die Entstehung der Anden: by ZDF/Terra X/Hanna Kotarba/Albrecht M. Wendlandt, https://commons.wikimedia.org/wiki/File:Die_Entstehung_der_Anden.webm Entstehung des Himalaya-Gebirges: by ZDF/Terra X/Faszination Erde/C. Götz-Sobel/O. Rötz/M. Zimmermann/Maximilian Mohr, https://commons.wikimedia.org/wiki/File:Entstehung_und_Quellen_des_Himalaya-Gebirges.webm depiction of Ur: by mrAnmol,https://commons.wikimedia.org/wiki/File:Artistic_depiction_of_Ur.png Tectonic plate: by Andrew Merdith, https://ru.wikipedia.org/wiki/%D0%A4%D0%B0%D0%B9%D0%BB:Tectonic_plate_model_1Ga.webm Ess2650: by Christopher R. Scotese, Ben A. van der Pluijm, https://commons.wikimedia.org/wiki/File:Ess2650-sup-0001-2019ea000989-ms10.webm CC BY-SA 3.0 https://creativecommons.org/licenses/by-sa/3.0/:  Pangaea-proxima: by Orolenial, https://commons.wikimedia.org/wiki/File:Pangaea-proxima250ma.jpg Tectonic plates: by M.Bitton, https://commons.wikimedia.org/wiki/File:Tectonic_plates_(2022).svg Animation is created by Bright Side.  ---------------------------------------------------------------------------------------- Music by Epidemic Sound https://www.epidemicsound.com   Check our Bright Side podcast on Spotify and leave a positive review! https://open.spotify.com/show/0hUkPxD34jRLrMrJux4VxV   Subscribe to Bright Side: https://goo.gl/rQTJZz  ---------------------------------------------------------------------------------------- Our Social Media: Facebook: https://www.facebook.com/brightside  Instagram: https://www.instagram.com/brightside.official TikTok: https://www.tiktok.com/@brightside.official?lang=en   Stock materials (photos, footages and other): https://www.depositphotos.com https://www.shutterstock.com https://www.eastnews.ru ----------------------------------------------------------------------------------------  For more videos and articles visit: http://www.brightside.me

Transcript

00:00Now, at first glance, it seems like we're on a giant raft, called a continent, that's

00:05just floating around on some molten lava until it hits another continent.

00:10Okay, let's make a quick stop at high school science class.

00:15Our home planet is like a cake, with different layers of ingredients stacked up on top of

00:21each other – the Earth's core, mantle, and crust.

00:25Hey, where's the frosting?

00:27The cake batter on top represents the crust of the Earth, made up of three types of tasty

00:33rock – igneous, sedimentary, and – say it with me – metamorphic.

00:39These rocks are formed in different ways, such as from solidified lava, or from the

00:44deposits of particles and minerals.

00:47The crust is what we stand on, a home to our continents, oceans, and everything we see

00:52around us.

00:54Then you have the mantle – not the baseball player – the layer that lies right below

00:58the crust.

01:00Many people think that the mantle is just lava, but it's not quite like that.

01:05Just like how you mix different ingredients in the cake batter, the mantle is made up

01:09of different types of rocks that are constantly moving and shifting.

01:14And finally, we get to the sweetest part of the cake – the center, or in the case of

01:19Earth, the core.

01:21It has two parts, the outer and inner core.

01:24The outer core is made of molten rocks and metals that are incredibly hot, even hotter

01:30than the surface of the Sun.

01:32The inner core is solid, even though temperatures there are crazy.

01:36It doesn't turn into liquid because the pressure down there is amazingly strong.

01:41When you see all this, you can easily think that below us there are endless miles of lava

01:47and hot rocks.

01:49So how come tectonic plates move at all?

01:53The continents don't float on a sea of molten rock.

01:56The oceanic and continental crusts really sit on a mantle.

02:00Sure, there's a layer of liquid rock in our planet, the outer core, around 1,800 miles

02:06below the surface.

02:08But it's separated from the surface by the mantle that's thick and solid.

02:13So the Earth's tectonic plates move around because they're on a thick layer of solid

02:19rock, the upper mantle.

02:21Basically, this rock is under incredible pressure and heat, which makes it flow in slow motion

02:27over time.

02:28Think of it like honey or syrup that you pour over your cake layers.

02:33As you move the cake around, the honey or syrup will also move and flow.

02:38Similarly, the upper mantle can flow and drag the parts above it along, just way slower

02:44than honey.

02:46And the rock is both breakable and flexible.

02:49It can crack and break like a cookie, now I'm getting hungry.

02:53But it can also stretch and bend like a piece of taffy.

02:56When the plates get caught on each other, they can't move anymore.

03:00But when they break free, they start drifting again, like puzzle pieces shifting around

03:05until they find their perfect fit.

03:09Extremely high temperatures and pressure are the reason this flow happens.

03:13It's like a big pot of soup on the stove.

03:15As the soup heats up, it starts to move around, carrying heat from one spot to another.

03:21Is it lunch time?

03:23And speaking of lunch, I mean lava, it's not just molten rocks that travel all the

03:28way up from the outer core to volcanoes.

03:31When tectonic plates come together and one slides underneath the other, they create a

03:36lot of heat and pressure while grinding against each other.

03:41It's like rubbing your hands together fast and they start to get hot.

03:45Or when you start a fire with rocks.

03:47And as the melted rock, or magma, rises to the surface, it can create volcanoes.

03:54Now long ago, the Earth's land was not divided into continents as it is today.

03:59Instead, there was one giant landmass, known as Pangaea, meaning all-Earth in Greek.

04:07Whoa, imagine being stuck in the middle of this giant ocean!

04:11So over time, this supercontinent slowly broke apart.

04:16Its parts drifted away from each other and formed the separate lands we call continents.

04:22This idea first popped out in the 16th century when one cartographer realized the coastlines

04:28of Africa, America, and Europe appear like they could fit together like puzzle pieces.

04:35Later researchers realized the rock composition of their coastlines was similar, which means

04:41they used to be part of one giant mass, and they call that the theory of continental drift.

04:47At first, people were pretty skeptical about that idea because they didn't know how such

04:52massive lands could move around.

04:55Now we'd all be able to explain that part, right?

04:58So the Earth's crust is divided into a couple of large plates and many smaller ones.

05:04All of them are still moving, even though it's in slow motion.

05:08We can't sense it, and we won't see any particular changes during our lifetime.

05:13It's a process that lasts hundreds of millions of years.

05:17As the plates move, they interact with one another in fascinating ways.

05:22For example, when two plates collide, one may be forced beneath the other, which would

05:28help create a subduction zone.

05:31Over time, this is the way you get many cool things like volcanic islands, trenches, and

05:36even entire mountain ranges.

05:39Plates apparently started moving around 3.5 billion years ago.

05:44It took them a while to group into the first jigsaw supercontinent we know about called

05:49Ur.

05:50Today, its remains make up parts of Madagascar, India, and Australia.

05:56Pangaea formed 335 million years ago, but it probably won't be the last continent

06:01that will form.

06:03So some new generations in the distant future could live on something called the next Pangaea.

06:10When the oceanic crust of the Atlantic Ocean slowly takes its place under the continental

06:16crust, the oceanic basin of the Atlantic is going to close, which is why the continents

06:21will end up pulled together.

06:24This means the Americas will meet Africa, and Eurasia will be flipped on its side.

06:30So people might live on a giant landmass in the shape of a ring, clustered around the

06:35inner sea, or at least what's left of it.

06:38Or maybe continents will take another direction and make up a different jigsaw puzzle called

06:44Amasia.

06:45In this scenario, the Americans will drift westward, fuse with Australia, and pivot to

06:51around Siberia.

06:53And then there's more.

06:54Novo Pangaea is the option where the Americas swing together to embrace Antarctica and Australia,

07:02and Africa legs off to the northwest.

07:04Basically, all continents here get together to form a giant landmass that stretches from

07:10one pole to the other.

07:12Ready for one more?

07:13Nah, come on.

07:15A recent projection called Aurica gives an idea similar to Novo Pangaea.

07:21It's just that all continents here unite to become one gigantic land that clusters

07:26around the equator.

07:28Hmm, maybe this would be my favorite one to live at, with the sunny weather and the beach

07:33all the time.

07:35And who knows what kind of magnificent trenches, mountains, islands, and other geological beauties

07:41we'd get with this giant supercontinent.

07:44Novo Pangaea broke up about 175 million years ago.

07:48As the Atlantic and Indian Oceans began to widen towards the east, the Ring of Fire was

07:54formed.

07:55It's a path that goes along the Pacific Ocean with so many frequent earthquakes and

08:00active volcanoes.

08:01This way, Eurasia was unable to cross this border and continue moving westward.

08:07And now, Eurasia could move laterally along the Ring of Fire.

08:11The subduction zones kind of act like a barrier that forces the tectonic plates to move in

08:17different directions.

08:18So Eurasia could eventually collide with the Americas and form something similar to Amasia.

08:25It would be cool to sit there, grab the popcorn, and watch it from the side.

08:30But this is something that won't happen for the next 50 million years at least.

08:34I'm willing to bet I probably won't be here to see it.

08:38Different theories talk about different positions where this new supercontinent might end up

08:43one day.

08:44But it seems it will probably be somewhere in the polar area, centered on what we today

08:50recognize as the Arctic Ocean.

08:54Not my cup of tea.

08:55Bring me back the sunny one.

08:57Wait, scratch that.

08:58Let's go eat.

09:01That's it for today, so hey, if you pacified your curiosity, then give the video a like

09:05and share it with your friends.

09:07Or if you want more, just click on these videos and stay on the Bright Side!

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