Why Continents Haven’t Sunk Into Lava Yet

0:00Now, at first glance, it seems like we're on a giant raft called a continent that's just floating around on some molten lava until it hits another continent. Okay, let's make a quick stop at high school science class. Our home planet is like a cake with different layers of ingredients stacked up on top of each other. The earth's core, mantle, and crust. Hey, where's the frosting? The cake batter on top represents the crust of the earth, made up of three types of tasty rock, igneous, sedimentary, and, say it with me, metamorphic. These rocks are formed in different ways, such as from solidified lava or from the deposits of particles and minerals. The crust is what we stand on. A home door, continents, oceans, and everything we see around us. Then you have the mantle, not the baseball player, the layer that lies right below the crust.

1:00Many people think that the mantle is just lava, but it's not quite like that. Just like how you mix different ingredients in the cake batter, the mantle is made up of different types of rocks that are constantly moving and shifting. And finally, we get to the sweetest part of the cake, the center, or in the case of earth, the core. It has two parts, the outer and inner core. The outer core is made of molten rocks and metals that are incredibly hot, out, even hotter than the surface of the sun. The inner core is solid, even though temperatures there are crazy. It doesn't turn into liquid because the pressure down there is amazingly strong. When you see all this, you can easily think that below us there are endless miles of lava and hot rocks. So how come tectonic plates move at all? The continents don't float on the sea of molten rock. The oceanic and continental crusts really sit on a mantle.

2:00Sure, there's a layer of liquid rock in our planet, the outer core, around 1800 miles below the surface, but it's separated from the surface by the mantle that's thick and solid. So the earth's tectonic plates move around because they're on a thick layer of solid rock, the upper mantle. Basically, this rock is under incredible pressure and heat, which makes it flow in slow motion over time. Think of it like honey or syrup that you pour over your cake layers.

3:03As you move the cake around, the honey or syrup will also move in flow. Similarly, the upper mantle can flow and drag the parts above it along, just way slower than honey. And the rock is both breakable and flexible. It can crack and break like a cookie, now I'm getting hungry. But it can also stretch and bend like a piece of taffy. When the plates get caught on each other, they can't move anymore. But when they break free, they start drifting again, like puzzle pieces shifting around until they find their perfect fit. Extremely high temperatures and pressure are the reason this flow happens. It's like a big pot of soup on the stove. As the soup heats up, it starts to move around, carrying heat from one spot to another. Is it lunchtime? And speaking of lunch, I mean lava, it's not just molten rocks that travel all the way up from the outer cord of volcanoes. When tectonic plates come together and when slides underneath the other, they create

4:06a lot of heat and pressure while grinding against each other. It's like rubbing your hands together fast and they start to get hot, or when you start a fire with rocks. And as the melted rock, or magma, rises to the surface, it can create volcanoes. Now long ago, the Earth's land was not divided into continents as it is today. Instead, there was one giant landmass, known as Pangaea, meaning all Earth and Greek. Whoa, imagine being stuck in the middle of this giant ocean. So over time, this supercontinent slowly broke apart. Its parts drifted away from each other and formed the separate lands we call continents. This idea first popped out in the 16th century when one cartographer realized the coastlines of Africa, America, and Europe appear like they could fit together like puzzle pieces. Later researchers realized the rock composition of their coastlines was similar, which means

5:11they used to be part of one giant mass and they called that the theory of continental drift. At first people were pretty skeptical about that idea because they didn't know how such massive lands could move around. Now we'd all be able to explain that part, right? So the Earth's crust is divided into a couple of large plates and many smaller ones. All of them are still moving, even though it's in slow motion. We can't sense it, and we won't see any particular changes during our lifetime. It's a process that lasts hundreds of millions of years. As the plates move, they interact with one another in fascinating ways. For example, when two plates collide, one may be forced beneath the other, which would help create a subduction zone. Exema is unpredictable, but you can blur a less with ebglyce, a once-monthly treatment for moderate to superior eczema. After an initial four-month or longer dosing phase, about four in ten people taking ebglyce,

6:13achieved itch relief and glare are almost glare skin at 16 weeks, and most of those people maintain skin that's still more glare at one year with monthly dosing. Ebglyce, Library Kizumap, LBKZ, a 250-mg per 2-ml injection is a prescription medicine used to treat adults and children 12 years of age and older who weigh at least 88 lbs or 40kg with moderate to severe eczema. Also called atopic dermatitis that is not well controlled with prescription therapies used on the skin, or topicals, or who cannot use topical therapies. Ebglyce can be used with or without topical corticosteroids. Don't use if you're allergic to ebglyce. A allergic reaction can occur that can be severe. Eye problems can occur. Tell your doctor if you have new or worsening eye problems. You should not receive a live vaccine when treated with ebglyce. Before starting ebglyce, tell your doctor if you have a parasitic infection. Ask a doctor about ebglyce and visit ebglyce.lily.com or call 1-800-LilyRx or 1-105-4-5-5-9-7-9. Over time, this is the way you get many cool things like volcanic islands, trenches, and even entire mountain ranges. Plates apparently started moving around 3.5 billion years ago.

7:14It took them a while to group into the first jigsaw supercontinent we know about called Urr. Today, its remains make up parts of Madagascar, India, and Australia. Pangaea formed 335 million years ago, but it probably won't be the last continent that will form. So, some new generations in the distant future could live on something called the next Pangaea. When the oceanic crust of the Atlantic Ocean slowly takes its place under the continental crust, the oceanic basin of the Atlantic is going to close, which is why the continents will end up pulled together. This means the Americas will meet Africa, and Eurasia will be flipped on its side. So, people might live on a giant landmass in the shape of a ring, clustered around the inner sea, or at least what's left of it, or maybe continents will take another direction and make up a different jigsaw puzzle called Amasia.

8:15In this scenario, the Americans will drift westward, fused with Australia, and pivot to a round Siberia. And then there's more. Novo Pangaea is the option where the Americas swing together to embrace Antarctica and Australia, and Africa legs off to the northwest. Basically, all continents here get together to form a giant landmass that stretches from one pole to the other. Ready for one more? Nah, come on. A recent projection called Orika gives an idea similar to Novo Pangaea. It's just that all continents here unite to become one gigantic land that clusters around the equator. Hmm, maybe this would be my favorite one to live at, with the sunny weather and the beach all the time. And who knows what kind of magnificent trenches, mountains, islands, and other geological beauties we'd get with this giant supercontinent. Pangaea broke up about 175 million years ago.

9:18As the Atlantic and Indian oceans began to widen towards the east, the ring of fire was formed. It's a path that goes along the Pacific Ocean with so many frequent earthquakes and active volcanoes. This way, Eurasia was unable to cross this border and continue moving westward. And now Eurasia could move laterally along the ring of fire. The subduction zones kind of act like a barrier that forces the tectonic plates to move in different directions. So Eurasia could eventually collide with the Americas and form something similar to Amazia. It would be cool to sit there, grab the popcorn, and watch it from the side. This is something that won't happen for the next 50 million years, at least. I'm willing to bet I probably won't be here to see it. Different theories talk about different positions where this new supercontinent might end up one day. But it seems it will probably be somewhere in the polar area, centered on what we today

10:20recognize as the Arctic Ocean. Not my cup of tea. Bring me back to sunny one. Wait, scratch that. Let's go eat. That's it for today. So hey, if you pacified your curiosity, then give the video a like and share it with your friends. Or if you want more, just click on these videos and stay on the Bright Side.