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There Are Mountains Deep Within the Earth
YouTube: | https://youtube.com/watch?v=lFnopD9Xzi4 |
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View count: | 287,197 |
Likes: | 13,571 |
Comments: | 618 |
Duration: | 03:39 |
Uploaded: | 2021-03-23 |
Last sync: | 2024-09-15 14:30 |
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Citation formatting is not guaranteed to be accurate. | |
MLA Full: | "There Are Mountains Deep Within the Earth." YouTube, uploaded by SciShow, 23 March 2021, www.youtube.com/watch?v=lFnopD9Xzi4. |
MLA Inline: | (SciShow, 2021) |
APA Full: | SciShow. (2021, March 23). There Are Mountains Deep Within the Earth [Video]. YouTube. https://youtube.com/watch?v=lFnopD9Xzi4 |
APA Inline: | (SciShow, 2021) |
Chicago Full: |
SciShow, "There Are Mountains Deep Within the Earth.", March 23, 2021, YouTube, 03:39, https://youtube.com/watch?v=lFnopD9Xzi4. |
Scientists think they’ve discovered some peaks taller than Mt Everest deep beneath the earth’s crust, and this range might be the key to one of the biggest mysteries in geology!
Hosted by: Stefan Chin
SciShow has a spinoff podcast! It's called SciShow Tangents. Check it out at http://www.scishowtangents.org
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Silas Emrys, Charles Copley, Drew Hart, Jeffrey Mckishen, James Knight, Christoph Schwanke, Jacob, Matt Curls, Christopher R Boucher, Eric Jensen, Lehel Kovacs, Adam Brainard, Greg, GrowingViolet, Ash, Laura Sanborn, Sam Lutfi, Piya Shedden, KatieMarie Magnone, Scott Satovsky Jr, charles george, Alex Hackman, Chris Peters, Kevin Bealer
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Sources:
https://science.sciencemag.org/content/363/6428/696
https://www.nationalgeographic.com/science/2019/03/rugged-mountains-taller-everest-lurk-deep-inside-earth/
https://science.sciencemag.org/content/363/6428/736
https://link.springer.com/article/10.1007/s11214-020-00649-y
https://www.smithsonianmag.com/science-nature/decades-long-quest-drill-earths-mantle-may-soon-hit-pay-dirt-180957908/
Image Sources:
https://www.usgs.gov/media/images/earth-cross-section
Hosted by: Stefan Chin
SciShow has a spinoff podcast! It's called SciShow Tangents. Check it out at http://www.scishowtangents.org
----------
Support SciShow by becoming a patron on Patreon: https://www.patreon.com/scishow
----------
Huge thanks go to the following Patreon supporters for helping us keep SciShow free for everyone forever:
Silas Emrys, Charles Copley, Drew Hart, Jeffrey Mckishen, James Knight, Christoph Schwanke, Jacob, Matt Curls, Christopher R Boucher, Eric Jensen, Lehel Kovacs, Adam Brainard, Greg, GrowingViolet, Ash, Laura Sanborn, Sam Lutfi, Piya Shedden, KatieMarie Magnone, Scott Satovsky Jr, charles george, Alex Hackman, Chris Peters, Kevin Bealer
----------
Looking for SciShow elsewhere on the internet?
Facebook: http://www.facebook.com/scishow
Twitter: http://www.twitter.com/scishow
Tumblr: http://scishow.tumblr.com
Instagram: http://instagram.com/thescishow
----------
Sources:
https://science.sciencemag.org/content/363/6428/696
https://www.nationalgeographic.com/science/2019/03/rugged-mountains-taller-everest-lurk-deep-inside-earth/
https://science.sciencemag.org/content/363/6428/736
https://link.springer.com/article/10.1007/s11214-020-00649-y
https://www.smithsonianmag.com/science-nature/decades-long-quest-drill-earths-mantle-may-soon-hit-pay-dirt-180957908/
Image Sources:
https://www.usgs.gov/media/images/earth-cross-section
{♫Intro♫}.
When you learned about the inside of the Earth, you might have learned that it’s made of nice, smooth layers: the crust, the upper mantle, the lower mantle, and so on. But the more we discover, the more we find out that that’s anything but true.
Like, scientists have found a whole mountain range between the upper and lower mantle. And these mountains might be the key to one of the biggest mysteries in geology: the case of Earth’s missing elements. Compared to meteorites and other nearby objects in our solar system, .
Earth seems to have lower amounts of certain elements, like silicon. Which is weird, because based on what we know about how the solar system formed, these objects should have come from the same disk of material. So, geologists have been trying to figure out literally where on Earth those elements are hiding.
The lower mantle was a prime suspect, because it and the core beneath it are the only big places we haven’t been able to look. The problem is, the lower mantle begins 660 kilometers underground — way too deep to just drill down to it. But it is possible to explore this part of the
Earth: . You just have to wait for a strong earthquake. Earthquakes send seismic waves through the planet, and how they travel can be affected by things like what kind of rock they’re passing through. So, measuring those waves can tell us something about Earth’s insides — including what the lower mantle is like.
Or more specifically, the boundary between the lower mantle and the upper mantle. At this boundary, an increase in pressure and temperature causes the minerals there to change phase:. Their atoms become more densely-packed, and 30 times more viscous than those above them.
And because of this change, some seismic waves can bounce off this boundary and be detected by seismometers. Now, interpreting these reflections is complex. But basically, if the boundary in the mantle is smooth, the waves will bounce off it and strike the seismometer at the same time. But if the boundary is rough, the reflections will be scattered, and they’ll strike the seismometer at slightly different times.
So in a 2019 study, researchers used reflected seismic waves to piece together what that lower mantle boundary looked like. Using data from 13 earthquakes, they mapped the top of the lower mantle — and realized it isn’t smooth at all. It’s full of huge mountains.
Like, 30 to 40 kilometers high! Mount Everest is only nine kilometers tall! Now, big features like this could signal that the mantle is hotter in one place or cooler in another.
This could slightly shift the point where the minerals change phase, and make the mantle boundary all jagged. But the researchers were pretty sure that wasn’t the case, because these mountains weren’t just tall. They were also rugged, full of bumps between one and three kilometers high.
And this can’t be explained by temperature differences, because fluctuations that small should even out over time. Instead, scientists believe that these bumps likely mark a chemical change — and that the mountains of the lower mantle are made of something different than the upper mantle. They hypothesized that these mountains could be ancient slabs of oceanic crust from the surface that have subducted and sunk down.
And instead of fully melting and mixing back into the mantle, they’re just sitting down there. If this is true, these slabs would block the circulation between the parts of the mantle and possibly form a treasure trove of Earth’s hidden elements — locked away since our planet’s early days. And even if the missing elements turn out to be somewhere else, this is a reminder that Earth is never as neat and tidy as it seems.
And that’s really a theme with everything out there. Like, the mantle also has some gigantic blobs in it, further disproving the idea that Earth is made of neat, concentric circles. If you want to learn more about what those blobs are and what they’re doing, you can watch our episode about it after this. {♫Outro♫}.
When you learned about the inside of the Earth, you might have learned that it’s made of nice, smooth layers: the crust, the upper mantle, the lower mantle, and so on. But the more we discover, the more we find out that that’s anything but true.
Like, scientists have found a whole mountain range between the upper and lower mantle. And these mountains might be the key to one of the biggest mysteries in geology: the case of Earth’s missing elements. Compared to meteorites and other nearby objects in our solar system, .
Earth seems to have lower amounts of certain elements, like silicon. Which is weird, because based on what we know about how the solar system formed, these objects should have come from the same disk of material. So, geologists have been trying to figure out literally where on Earth those elements are hiding.
The lower mantle was a prime suspect, because it and the core beneath it are the only big places we haven’t been able to look. The problem is, the lower mantle begins 660 kilometers underground — way too deep to just drill down to it. But it is possible to explore this part of the
Earth: . You just have to wait for a strong earthquake. Earthquakes send seismic waves through the planet, and how they travel can be affected by things like what kind of rock they’re passing through. So, measuring those waves can tell us something about Earth’s insides — including what the lower mantle is like.
Or more specifically, the boundary between the lower mantle and the upper mantle. At this boundary, an increase in pressure and temperature causes the minerals there to change phase:. Their atoms become more densely-packed, and 30 times more viscous than those above them.
And because of this change, some seismic waves can bounce off this boundary and be detected by seismometers. Now, interpreting these reflections is complex. But basically, if the boundary in the mantle is smooth, the waves will bounce off it and strike the seismometer at the same time. But if the boundary is rough, the reflections will be scattered, and they’ll strike the seismometer at slightly different times.
So in a 2019 study, researchers used reflected seismic waves to piece together what that lower mantle boundary looked like. Using data from 13 earthquakes, they mapped the top of the lower mantle — and realized it isn’t smooth at all. It’s full of huge mountains.
Like, 30 to 40 kilometers high! Mount Everest is only nine kilometers tall! Now, big features like this could signal that the mantle is hotter in one place or cooler in another.
This could slightly shift the point where the minerals change phase, and make the mantle boundary all jagged. But the researchers were pretty sure that wasn’t the case, because these mountains weren’t just tall. They were also rugged, full of bumps between one and three kilometers high.
And this can’t be explained by temperature differences, because fluctuations that small should even out over time. Instead, scientists believe that these bumps likely mark a chemical change — and that the mountains of the lower mantle are made of something different than the upper mantle. They hypothesized that these mountains could be ancient slabs of oceanic crust from the surface that have subducted and sunk down.
And instead of fully melting and mixing back into the mantle, they’re just sitting down there. If this is true, these slabs would block the circulation between the parts of the mantle and possibly form a treasure trove of Earth’s hidden elements — locked away since our planet’s early days. And even if the missing elements turn out to be somewhere else, this is a reminder that Earth is never as neat and tidy as it seems.
And that’s really a theme with everything out there. Like, the mantle also has some gigantic blobs in it, further disproving the idea that Earth is made of neat, concentric circles. If you want to learn more about what those blobs are and what they’re doing, you can watch our episode about it after this. {♫Outro♫}.