Questions tagged [core]

For questions about the Earth's core. The center of the Earth is primarily iron-nickel.

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Why is the inner core about 85% iron and the rest (mostly) nickel, while the outer is roughly 80%/20%, if nickel is denser than iron?

As stated above.... I really cannot think of a good reason, on my own, why this should be so.... Is it a mystery to geologists?
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How much does earth's core temperature affect earth's global surface temperature

Has anyone managed to read the (latest) full IPCC-report and do you know whether they have taken into account the Earth's core temperature in their models. Besides the IPCC-report, do we know how much ...
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Can changing magnetic fields or a solidifying core cause the Earth to rotate faster?

I had a small quarrel about this on the physics site. A question was asked about what could cause a change in the rotation speed of the Earth. In addition to the answers given I proposed the ...
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What would happen if the inner core bulged and moved a tiny bit?

The inner core is solid only because of the very high pressure of the outer core and mantle . Say, if the inner core moved a teeny tiny bit would some of it liquify and melt? Or does it stay solid? ...
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Can there be ice in the core because of pressure?

Because there is so much pressure in the earth's core, the inner core is solid but what happens if you manage to add some water in the inner core or near it. Does the pressure make the water solid or ...
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How much role does radioactivity play in making Earth geologically active [duplicate]

A hot molten core is important for making the Earth geologically active. I believe most of the heat is from the time of the planet formation, and the high pressures due to everything pushing down to ...
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How do scientists confirm iron core at the centre of the earth?

How do scientists confirm iron core at the centre of the earth? We know scientists couldn’t yet drill to the core of our planet earth. Yet we know they confirmed there is a core of iron at the centre ...
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How do we know the speed of S-waves (shear waves) in the Earth's inner core? Has this been measured?

Wikipedia's Seismic wave includes the plot below of the speed of S and P waves as a function of depth in the Earth. In the region of the outer core the speed of S-waves or shear waves is shown to be ...
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Do we know anything about the nature of Earth's core that hasn't come from magnetic or seismic measurements?

There is much known about Earth's core from painstaking analysis of seismic data, and from detailed magnetic field maps and trends over time. Are there any other measurements that have contributed to ...
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Are we experiencing lower level of gravity now compared to past?

Whole civilizations have been buried underground and we have built new landscapes over them. The fact that tall buildings and houses are being excavated from under the ground means that we are living ...
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On the solidity of the Earth's core [duplicate]

From what I know from various textbooks, pop-science shows and my classes, the earth's core is solid. But how does the concept of solid and liquid make sense at these high temperatures.
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If the earth's core is made up of copper/other metals other than iron-nickel alloy, how our magnetosphere will be?

We know that our earth's core is made up of iron-nickel alloy and it is spinning to create magnetic flux all around our planet to create our life-saving Magnetosphere. And this also influences our 9.8 ...
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How was the Earth's core made?

All I've heard until now is that when the Earth was very hot and slimy, the relatively heavier elements went down to the center of the Earth to form the core. But lately I've come up a contradiction ...
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How Can We Establish Precisely What Earth's Core is Made Of?

The consensus view is that that the Earths core is composed mainly of iron alloyed with about 10 percent nickel and traces of other heavy metals, but I have seen at least one account which says it is ...
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Why doesn't the Earth's outer core dissolve into the mantle?

It is well accepted that the outer core is made out of liquid iron and nickel, and as everything else it should tend to reach chemical equilibrium with its surrounding. In particular, I would expect ...
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Why the "Mission to Earth’s core" proposal suggests using liquid iron instead of lead?

Nature communications article "Mission to Earth's core — a modest proposal", suggests placing a large volume of liquid iron in a crack and let it sink all the way to the Earth's core, carrying along a ...
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Why is the core of Earth in a reduced state? ($\text{Fe}$ and $\text{Ni}$)

I understand gravitational differentiation caused the layered structure of Earth when it is still molten. However, why are the heavier constituents in a reduced state, i.e. metal $\text{Fe}$ and $\...
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By how much did the Earth's diameter decrease due to cooling, if at all, since it was formed?

The answer to How long until Earth's core solidifies? question cites an estimation that the Earth (as a planet, not the surface of it) has cooled down by about 250K since it was formed. The question ...
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Do there exist reasonable numbers on the density/radius/mass of the various geological layers of the Earth?

I've been doing some math on the radius of the core (inner core in particular), and I keep getting what look like nonsense results. The composition is supposedly nearly all iron, close enough to it ...
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How much does the Earth's center of mass move around?

How much does the Earth's center of mass move around relative to the most stationary objects on the surface? I'm wondering whether the molten outer core has enough asymmetry to move the center of ...
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What if we detonated the entire worlds nuclear supply in the center of the earth? [closed]

What would the effects of detonating every single nuclear bomb currently in existence at once in the center of the earth? Would the earth simply explode into bits? Would the heat have some sort of ...
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Does the Earth 'Flare' like the Sun does?

Solar Flares are a commonly discussed phenomenon, which have effects ranging from geomagnetic storms to radio disruptions to absolutely nothing noticeable. Given that part of the core of the Earth ...
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How do we know what Earth's core is made of? [duplicate]

There are many graphic representations of the Earth's core, but I would like to know how did scientists determine what the core is made of, how hot it is, rotation etc. without actually being there?
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Is the iron on Earth's crust a leftover of the Iron catastrophe, or it was brought back by volcanoes?

When pondering the hypothesis of the Iron catastrophe, that seem to be widely accepted nowadays. It surprises me that currently the crust still contain a significant amount of Iron (5.6% in weight). ...
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How much would a nine inch slice of the Earth's inner core weigh? [closed]

If one took a slice of the Earth's inner core measuring nine inches across how much would that slice weigh? Or, conversely, how much mass would that contain?
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Why is the Inner Core of the Earth solid in spite of being the deepest and the hottest layer of the Earth [duplicate]

I have been recently studying about the layers of the earth and I got stuck with the question that why is the inner core of the Earth solid in spite of being the deepest and the hottest layer. I hope ...
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Earth's inner core has an inner core inside itself. Are there three inner cores?

The Seeker.com article Earth's Inner Core Has Its Own Inner Core states that researchers at University of Illinois and Nanjing University in China have made a bizarre discovery. They've found that ...
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Are there any signs on the Earth's surface that indicate a shrinking iron core? [duplicate]

It appears that Mercury shows some cracks on its surface that were not caused by moving tectonic plates but by shrinking due to the inner metal core cooling. The Earth is also cooling down, but are ...
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How much of the Earth's heat is caused by the hot centre?

What is the percentage of the Earth's warmth that the Earth's hot centre is responsible for? What would be the temperature of the atmosphere if the Earth's centre was 18° C (average temperature on the ...
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Are Helium 3 and 4 being produced by earth's core?

J. Marvin Herndon claims that the evidence of the georeactor comes from 3He/4He ratios released to the oceans at the mid oceanic ridges. Georeactor-produced 3He/4He ratios are related to the extent of ...
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7 votes
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Does Earth's magnetic field arise from a fission reactor in its core?

I heard about the georeactor hypothesis (Herndon, 1993), which claims that there is a natural atomic fission reactor in the Earth's core giving rise to the geomagnetic field. Further, Herndon claims ...
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How fast does the Earth's inner-core spin?

How fast does the Earth's inner-core rotate compared to the Earth's daily rotation? The inner core is always described as a spinning/rotating solid core while the Earth has a single revolution per ...
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Why is the core of the earth thought to be iron rather than metallic oxygen? [duplicate]

The pressure at the top of the core is about 1 million bar. That should be enough to create metallic oxygen. So why is the core thought to be iron rather than just metallic oxygen?
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As the earth's core cools, will the size be affected?

Objects can change in size when their temperature changes. I'm wondering whether the cooling of the earth's core will affect it's size? Or will the change be insignificant due to the elements and ...
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Does iron in core have chance to come out to crust?

Is the iron in the inner core of Earth trapped forever? Are there any mechanisms that allow some iron to leave the core and come to the surface (eg: magma convention)?
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Does the Earth's core have the same rotation period as its surface? [duplicate]

Does the Earth's core have the same rotation period as the surface?
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Why is uranium only in the crust, really?

As I know, uranium is currently thought that it is mainly in the crust and not in the core or in the mantle. The reason for that it is a siderophile element which means it won't be solved in molten ...
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How is known that the Earth core is solid?

As I know, the Earth core is solid. This is known, because it conducts also transverse waves, while liquids conduct only longitudinal waves. But, how was it found? The inner core is in the outer core,...
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Why is Earth's Core Iron?

The two major constituents of the Earth's core are iron and nickel. In documentaries and scientific conversations, iron gets more attention than nickel, probably because it makes up a bigger ...
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Digging depth and heat

I have a question about the underground heat at different distances from the core of the Earth. I was wondering if there was a depth at which you can dig that the decrease in heat (as a result of ...
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21 votes
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What percent of the Earth's core is uranium?

What percent of the Earth's core is uranium? And how much of the heat at the core is from radioactive decay rather than other forces?
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How isotropic is the Earth's inner core boundary?

Often, in texts (particularly for schools etc) depict a smooth spherical isotropic boundary between the inner and outer core, as shown in the image from this USGS public education page: The inner ...
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12 votes
1 answer
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Why does seismic activity shed light on the inner core rigidity?

Reading Introduction to Geology (MIT 2005) and Wikipedia's article on Earth's inner core, it is specified that: Earth was discovered to have a solid inner core distinct from its liquid outer ...
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At what point does plate tectonics stop?

As the core and mantle of the earth cools, it will reach a point where new crust cannot be produced. How can this point be calculated? If we can, has anyone done such calculations? Thanks!
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16 votes
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How much silicon is in the Earth's core, and how did it get there?

With some informal conversation with a peer of mine, he had suggested that there is evidence (which he couldn't find,but had remembered reading) that there was Silicon in the Earth's core. I referred ...
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How long until Earth's core solidifies?

How much longer does Earth have until the core turns solid? Does global warming change these estimates at all?
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11 votes
5 answers
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Which theory is stronger, that iron came from outside or was formed within earth?

Where is the current body of science learning towards, that iron came from meteor or it was somehow formed on earth?
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28 votes
3 answers
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Why is Earth's inner core made of an iron-nickel alloy?

This question has puzzled me for a while. I know that earth's mantle is made of different minerals, metals and rocks etc. and that has always made complete sense to me. But why is the inner core made ...
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Why is Earth's outer-core liquid?

The Earth's inner core is solid because despite the enormous temperature in this region, there is also enormous pressure there, which in turn raises the melting point of iron and nickel to a value ...
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Why is Earth's inner core solid?

I have never understood why earth's inner core is solid. Considering that the inner core is made of an iron-nickel alloy (melting point around 1350 C to 1600 C) and the temperature of the inner core ...
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