At the earths core

February 6, Format: Blu-rayVerified Purchase I collect classic sci-fi films from the 60's on and thus purchased At the Earth's Core as soon as it was available. I was not disappointed. Watching a guy in a big bird suit stomp around after Peter Cushing is about as good as it gets for this sci-fi lover.

At the earths core

The central point of the Earth is over 6,km down, and even the outermost part of the core is nearly 3, km below our feet. All the familiar events on Earth also happen close to the surface. The lava that spews from volcanoes first melts just a few hundred kilometres down. Even diamonds, which need extreme heat and pressure to form, originate in rocks less than km deep.

And yet, we know a surprising amount about the core. We even have some idea about how it formed billions of years ago — all without a single physical sample.

This is how the core was revealed. It turns out that the mass of the Earth is 5. The next step is to ask which heavy materials make up the core. An iron core would account for all that missing mass The main At the earths core for this is the huge amount of iron in the universe around us.

It is one of the ten most common elements in our galaxy, and is frequently found in meteorites. Given how much there is of it, iron is much less common at the surface of the Earth than we might expect. So the theory is that when Earth formed 4.

But wait a minute. How did that iron get down there in the first place? View image of The San Andreas fault can trigger major earthquakes Credit: Most of the rest of the Earth is made up of rocks called silicates, and molten iron struggles to travel through them.

Rather like how water on a greasy surface forms droplets, the iron clings to itself in little reservoirs, refusing to spread out and flow. The pressure actually changes the properties of how iron interacts with the silicate A possible solution was discovered in by Wendy Mao of Stanford University in California and her colleagues.

They wondered what happened when the iron and silicate were both exposed to extreme pressure, as happens deep in the earth. By pinching both substances extremely tightly using diamonds, they were able to force molten iron through silicate.

At this point you might be wondering how we know the size of the core. What makes scientists think it begins km down? All the seismic stations dotted all over the Earth recorded the arrival of the tremors When an earthquake happens, it sends shockwaves throughout the planet.

Seismologists record these vibrations. Early in the history of seismology, it was realised that some vibrations were going missing. These "S-waves" were expected to show up on one side of the Earth after originating on the other, but there was no sign of them.

It turned out that rocks became liquid around km down The reason for this was simple. They must have come up against something molten in the centre of the Earth. That suggested the entire core was molten.

But seismology had another surprise in store. In the s, a Danish seismologist named Inge Lehmann noticed that another kind of waves, called P-waves, unexpectedly travelled through the core and could be detected on the other side of the planet.

P-waves really were travelling through the core She came up with a surprising explanation: The "inner" core, which begins around 5,km down, was actually solid.

It was only the "outer" core above it that was molten. Sure enough, they still ended up on the other side of the planet. In fact, seismology owes a lot of its success to the development of nuclear weapons. A nuclear detonation also creates waves in the ground, so nations use seismology to listen out for weapons tests.

During the Cold War this was seen as hugely important, so seismologists like Lehmann got a lot of encouragement. Seismology is still used to detect nuclear detonations today. But there is a lot more to try and tease out, especially about the inner core. For starters, how hot is it?

They subjected pure iron to pressures a little over half that at the coreand extrapolated from there.Earth's Core Is More Than Just A Store: It's a step into a whole new way of engaging your senses. You can spend hours perusing the thousands of different types of stones and marvel at the artistic majesty of nature herself while studying the colorful marvel of a "made by nature" Geode.

Iron is a relatively dense element under normal conditions, and under the extreme pressure at the Earth's core it would be crushed to an even higher density, so an iron core would account for all.

The inner core is solid, but the outer core is a hot liquid. Scientists think that movements of metal, like currents in the oceans, create the magnetic field that surrounds the Earth.

Iron is a relatively dense element under normal conditions, and under the extreme pressure at the Earth's core it would be crushed to an even higher density, so an iron core would account for all.

Earth's core is the deepest, hottest layer, and it's made up of two layers itself: the outer core which borders the mantle and the inner core, which is a ball-shaped layer made almost entirely of metal. Oct 10,  · miles below the Earth's surface, there is a vast ocean of molten iron.

At the earths core

The spinning outer core of the Earth generates a protective magnetic shield around the planet, defending life from.

BBC - Earth - How we know what lies at Earth's core