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 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 ...
tux's user avatar
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35 votes
4 answers
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How can we determine the size and composition of Earth's inner core?

From Wikipedia: Earth's inner core is Earth's innermost part and is a primarily solid ball with a radius of about 1,220 km (760 mi). (This is about 70% of the Moon's radius.) It is believed to consist ...
Ben A. Noone's user avatar
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31 votes
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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 ...
Kenshin's user avatar
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30 votes
3 answers
45k views

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 ...
tux's user avatar
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26 votes
7 answers
13k views

Could the Earth's core lose its heat?

Will all the drilling and digging to use the Earth's natural heat as geothermal energy affect the Earth's core, causing it to cool down? If so, would it result in an ice age? If not, how does the ...
tux's user avatar
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23 votes
3 answers
10k views

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?
Steve Farkus's user avatar
18 votes
1 answer
53k views

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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17 votes
2 answers
2k views

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!
rnrneverdies's user avatar
16 votes
6 answers
7k views

Is the Earth's hot inner core necessary for life?

The inner core of the Earth has an enormous temperature of around 4300 degrees Celsius. Is this large inner core temperature an important factor contributing to the ideal temperature that is ...
Kenshin's user avatar
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16 votes
1 answer
514 views

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 ...
Neo's user avatar
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14 votes
4 answers
12k views

Can we really travel through earth's core?

Inspired by the movie, "The Core". Can we really travel through earth's core? I will provide 2 sub questions: Is there any substance that can resist the heat of earth's core? Between the crust and ...
Poomrokc The 3years's user avatar
13 votes
1 answer
1k views

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,...
peterh's user avatar
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12 votes
3 answers
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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 ...
JohnWDailey's user avatar
12 votes
3 answers
4k views

Why does Earth's outer-core rotate in the opposite direction to the inner-core?

Is it true that Earth's outercore rotates in the opposite direction to Earth's inner-core? Is there a plausible explanation for why this phenomenon occurs and what is the available evidence ...
Kenshin's user avatar
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12 votes
1 answer
239 views

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 ...
Chirac's user avatar
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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?
public static's user avatar
11 votes
3 answers
268 views

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 ...
Michael Walsby's user avatar
10 votes
1 answer
4k views

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 ...
EveryBitHelps's user avatar
9 votes
1 answer
1k views

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 ...
user avatar
9 votes
1 answer
756 views

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). ...
Camilo Rada's user avatar
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8 votes
0 answers
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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 ...
DDRRSS's user avatar
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0 answers
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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 ...
Marijn 's user avatar
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7 votes
1 answer
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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 ...
Radja Callier's user avatar
7 votes
1 answer
721 views

How does the rotation of Earth's inner core influence climate?

In the recent paper published in Nature that sugests a 60-70 years inner core rotation cycle, it is said: Interestingly, the same multidecadal periodicity is also well observed in the Earth’s climate ...
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7 votes
3 answers
296 views

Does the high pressure inside the Earth's core contribute to its high temperature?

The explanations for why the Earth's core is hot I found on the internet included: leftover energy from the Earth's formation radioactivity of the elements inside the core friction between the core ...
Probably's user avatar
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7 votes
1 answer
302 views

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 ...
Radja Callier's user avatar
6 votes
2 answers
14k views

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 ...
I should change my Username's user avatar
6 votes
2 answers
843 views

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 ...
Camilo Rada's user avatar
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6 votes
0 answers
75 views

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 ...
torbjorn's user avatar
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5 votes
3 answers
7k views

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 ...
Bej's user avatar
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5 votes
2 answers
248 views

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?

The question is basically the title. I really cannot think of a good reason. Is it a mystery to geologists?
Kurt Hikes's user avatar
5 votes
1 answer
129 views

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 ...
Onyz's user avatar
  • 153
5 votes
1 answer
1k views

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 ...
peterh's user avatar
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5 votes
2 answers
183 views

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 $\...
Meatball Princess's user avatar
5 votes
2 answers
2k views

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 ...
tt_Gantz's user avatar
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5 votes
0 answers
131 views

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 ...
Wiz Kid's user avatar
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4 votes
3 answers
508 views

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 ...
Tardy's user avatar
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4 votes
1 answer
964 views

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 ...
user avatar
4 votes
1 answer
158 views

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)?
Gstestso's user avatar
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4 votes
1 answer
60 views

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 ...
John O's user avatar
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3 votes
4 answers
382 views

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 ...
uhoh's user avatar
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3 votes
4 answers
3k views

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 ...
Natural Number Guy's user avatar
3 votes
3 answers
616 views

If the Earth's core were made up of copper/other metals other than iron-nickel alloy, what would the magnetosphere be like?

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....
Kautham Krishna's user avatar
3 votes
1 answer
107 views

If the universe (and our galaxy) has about twice as many oxygen atoms as carbon ones, why does Earth have 300 times as many oxygen atoms as carbon?

A (relatively) recent 'Sky & Telescope' magazine feature story mentioned how little carbon the Earth has, and how some scientists' models predict we should somehow have even less.... So I looked ...
Kurt Hikes's user avatar
3 votes
1 answer
133 views

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 ...
Probably's user avatar
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3 votes
0 answers
32 views

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?
Chris's user avatar
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2 votes
1 answer
251 views

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 ...
Camilo Rada's user avatar
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2 votes
1 answer
88 views

Is there superionic ice in the earth? and how did it get there?

I recently researched about Superionic Ice which basically is Water under so much pressure and heat that it turns into a black hot ice. I read this article about it too. I found out Superionic ice ...
Tardy's user avatar
  • 574
2 votes
1 answer
100 views

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? ...
Tardy's user avatar
  • 574
2 votes
1 answer
99 views

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 ...
schizoid_man's user avatar