Questions tagged [core]

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

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34
votes
4answers
13k views

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 ...
24
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7answers
11k 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 ...
16
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2answers
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!
12
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3answers
6k views

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 ...
4
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1answer
576 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 ...
36
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3answers
33k views

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 ...
20
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3answers
6k 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?
18
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1answer
49k 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?
16
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5answers
6k 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 ...
14
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4answers
6k 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 ...
11
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3answers
3k 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 ...
25
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3answers
36k 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 ...
6
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2answers
295 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 ...
30
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4answers
34k views

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 ...
12
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1answer
207 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 ...
7
votes
1answer
380 views

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 ...
9
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3answers
199 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 ...
5
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2answers
971 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 ...
5
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2answers
102 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 $\...
3
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3answers
272 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 ...
2
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1answer
133 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 ...
1
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1answer
66 views

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 ...