ESC 1000 Video Notes Name: _________________
Inside Planet Earth (2009)
It's the ultimate voyage our world has to offer: a journey from the temperate surface of our world to the fiery core of the Earth. With the aid of stunning visual effects, the unexplored interior of the Earth is split wide open, giving us an unbelievable view. From glowing seams of pure iron ore to sparkling diamond caverns to the magnetic field that keeps us safe from the lethal radiation of space... for now, this is the fantastical world we live in -- and never see.
From the heights of Mount Everest to the molten lava fields of
How thick is the crust?
How deep into the crust has man gone?
How deep into the crust has man drilled?
Is the mantle molten?
What is a mantle plumb?
Jessika Toothman, HowStuffWorks.com
The Earth's core is not directly accessible to scientists, so they've been forced to ingeniously develop a variety of novel approaches to glean information about the churning hot center of our planet.
Journey to the Center of the Earth
First let's refresh on what we do know about the individual layers of differentiation lying beneath our feet. Traveling down through the crust of the Earth, the first major boundary we reach is the Mohorovicic (Moho) discontinuity, past which we're now in the mantle.
Researchers have been attempting to penetrate the Moho for a number of years, and another effort is currently underway. One of the objectives of the Integrated Ocean Drilling Programme (IODP) is to drill through the planet's crust by tunneling through the ocean floor.
According to Paul Parsons of the Telegraph, "The IODP has
already reached the lower part of the crust, by drilling at a part of the
After we pass through the mantle -- no small task considering about 83 percent of the Earth's volume is contained within it -- we reach the core. This isn't some little nugget cuddled in the center of the planet either; the core is approximately equal to the size of Mars.
Split into two portions, the outer core -- likely a molten layer of liquid iron with some additional elements thrown into the mix -- surrounds the inner core, which is basically a super-hot solid hub of metallic elements, also primarily iron. But if the mantle contains most of the earth's volume, the combined cores take the cake in terms of mass: about 67 percent of the planet's mass lurks within its ultra-dense center.
Studying Seismic Waves
Probably the most well-known method for peering into the depths of the planet is through the use of seismic waves. Measuring the wave patterns that shoot through the Earth when an earthquake strikes helps to distinguish between the various layers buried far below.
This happens because the shock waves travel at different speeds through different mediums. They move quickly through rocks, for example, but more slowly through fluids, and passing from one substance to the next can also deflect the direction of their paths. In some cases, the waves won't penetrate a certain material at all, creating shadow zones around the globe.
Satellite Imagery and Magnetic Fields
Another way scientists can learn about the Earth's core is by measuring fluctuations in the planet's magnetic field. That's because one of the major factors affecting the magnetosphere is the convective motion of all that swirling molten liquid thousands of miles below the surface of the earth.
So by studying the alterations in intensity of the earth's magnetic field, researchers have been able to get a better understanding of the attributes of the Earth's core.
"What is so surprising is that rapid, almost sudden, changes take place in the Earth's magnetic field," says Nils Olsen, senior scientist with DTU Space, a department of the Technical University of Denmark. "This suggests that similar sudden changes take place in the movement of the liquid metal deep inside the Earth which is the reason for the Earth's magnetic field."
Olsen was lead author of a study published by Nature Geoscience in May of 2008, in which satellite data collected over nine years was used to study the planet's magnetic field. The findings concluded that it could be altered in as little as a few months time.
Article posted April 6, 2009.
Humans have explored the moon a quarter million miles away, yet more than 99 percent of Earth remains unexplored. But this final frontier isn't on the surface of the Earth. Below the rainforests and the mountains are thousands of miles of inaccessible rock and metal, searing heat, and crushing pressure. But what if a crack could be opened all the way to the center of the Earth? The Earth is like an onion, divided into layers. Each layer plays a vital role in making the world a place where life can survive. Above Ground: The outermost layer, the atmosphere, is painfully thin. It makes up just one percent of the volume of the planet. The journey begins by discovering what it's like to freefall through 19 miles of atmosphere -- a feat accomplished by American legend Joe Kittinger in the 1960s.
· Ground Level: Plunging through the crust, discover how the Earth's inner heat breaks up this layer into multiple continental rafts, the tectonic plates.
· 1000 Feet Inside Earth: Broken strata and faulted layers created by the process of mountain building. See the awe inspiring effect of underground erosion inside the spectacular Carlsbad Caverns.
· 1.5 Miles Inside Earth: Float past seams of coal to understand the role the crust plays in conserving life on Earth. The crust is a vast reservoir of carbon. At Georgia's Okefenokee Swamp discover how coal is made.
· 2.5 Miles Inside Earth: Find gold in the deep-level mines of South Africa and discover life that can exist up to 7 miles inside Earth, surviving radiation and 130-degree heat, and living on nothing more than iron.
· 20 Miles Inside Earth: Glowing seams of red rock, pure iron ore, laid down in massive volumes by early photosynthesising bacteria.
· 30 Miles Inside Earth: Cross the Moho, the boundary layer between crust and mantle. Discover the significance of this bizarre fudge-like layer and how it acts like a lubrication layer for plate tectonics. Walk along a beach made of Moho in Cornwall, England.
· 100 Miles Inside Earth: Dive deep into the mantle, full of convecting magma and diamond caverns.
· 1500 Miles Inside Earth: Find a place populated by awesome chemical horizons and magnificent mantle plumes 2000 mile high.
· 2000 Miles Inside Earth: Cross into the Core to discover how this moon-sized sphere of molten iron is the Earth's Great Magnet, generating a magnetic field that keeps humans safe from the lethal radiation of space...or is it? Evidence suggests the magnetic field is experiencing a significant wobble and could even be in the early stages of shut down. Mars and its history suggest what Earth would be like if the magnetosphere vanished.
· 3100 Miles Inside Earth: Underground metallic forests growing on the Inner Core, potted divots, and vast subterranean mountains.
· 3981 Miles Inside Earth: The Center of the Earth, where gravity is absent...