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19 votes
Accepted

Are we experiencing lower level of gravity now compared to past?

Earth's radius is about 6400 kilometres. That's 6400000 metres. Let's say that you have a mound 20 metres high, burying an older settlement. Your new "radius" is now 6400020 metres. Let's say that $g ...
Gimelist's user avatar
  • 23.1k
14 votes

Does Earth's magnetic field arise from a fission reactor in its core?

The conventional explanation for the Earth's magnetic field is that some combination of differential rotation and/or convection occurs in the Earth's outer core, primarily in molten iron-nickel (+ ...
Gordon Stanger's user avatar
13 votes
Accepted

How is known that the Earth core is solid?

This is a good observation. The reason we can measure S-wave (transverse) propagation in the inner core is because P-waves can set up S-waves and vice versa. When an S-wave hits the mantle-outer core ...
bon's user avatar
  • 2,211
11 votes
Accepted

How fast does the Earth's inner-core spin?

Roughly once per day, but a tiny bit faster. As the website for Columbia University's Lamont-Doherty Earth Observatory says: The inner core rotates in the same direction as the Earth and slightly ...
Spencer's user avatar
  • 3,638
9 votes
Accepted

Is the iron on Earth's crust a leftover of the Iron catastrophe, or it was brought back by volcanoes?

Not all the iron sank to the core. Have a look at my answer to a previous question: https://earthscience.stackexchange.com/a/7076/725 Your question is similar, but coming the other way. You're ...
Gimelist's user avatar
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8 votes
Accepted

What if we detonated the entire worlds nuclear supply in the center of the earth?

I'll ignore the complete impossibility of getting the world's nuclear arsenal to the center of the Earth and the impossibility of exploding them all at once. The total number of nuclear weapons, ...
David Hammen's user avatar
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8 votes
Accepted

How do scientists confirm iron core at the centre of the earth?

This is more a geophysics than an astronomy question—and thus the available methods of investigation are greatly increased. An Earth model also is not a one-person-show based on one measurement, but ...
planetmaker's user avatar
8 votes

How much does earth's core temperature affect earth's global surface temperature

It's not the earth's core temperature per se that matters, but rather the amount of heat that flows from the core to the surface. Just like holding a cup of hot coffee - if the mug is insulated, it's ...
Ed Doddridge's user avatar
7 votes
Accepted

Does the Earth 'Flare' like the Sun does?

The medium for a solar flare is plasma, so nothing like that occurs in the Earth's core. The outer core fluid is highly conductive and has a low viscosity, so changes may occur in the core's field, ...
A. Newell's user avatar
  • 288
7 votes
Accepted

Does iron in core have chance to come out to crust?

No, we occasionally get fragments of upper mantle overthrust onto the Earth's crust, but then the specific gravity (density) contrast is not so great, roughly 2.7 to 3.0 for crust, about 3.2 for ...
Gordon Stanger's user avatar
7 votes
Accepted

Can there be ice in the core because of pressure?

what happens if you manage to add some water in the inner core or near it. It will probably react with the solid iron to form iron (oxy)hydride: Our observations indicate that H2O is likely ...
Gimelist's user avatar
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6 votes
Accepted

Why is uranium only in the crust, really?

(tl;dr below) First, a correction. Siderophile elements are "iron-loving" elements, those that go in the core with the Fe-Ni liquid. Uranium is lithophile, or "rock-loving". It partitions to silicate ...
Gimelist's user avatar
  • 23.1k
6 votes

How Can We Establish Precisely What Earth's Core is Made Of?

We know the density of the core from seismology. We also know the density of pure iron at given pressure (P) and temperature (T). From these two, people have long noticed that there is a discrepancy: ...
Jean-Marie Prival's user avatar
6 votes

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?

Once you're in the metallic part of the Earth, the compositions of the different constituents (solid and liquid) are not determined by density. The whole metallic part (core) is denser the the ...
Gimelist's user avatar
  • 23.1k
6 votes
Accepted

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

I have four things to say regarding this: The paper is far too new. I'm not saying the first paper is wrong (it is in fact rather interesting), but having been published yesterday, it is far too new ...
David Hammen's user avatar
  • 23.7k
5 votes

Why doesn't the Earth's outer core dissolve into the mantle?

From the comments: And indeed, after browsing trough a few sections they seem to assume that "Liquid metal separates rapidly from liquid silicate", like oil and water, and they don't mix ...
Gimelist's user avatar
  • 23.1k
5 votes

Are we experiencing lower level of gravity now compared to past?

To address your original concern, no, the fact that there are buildings underground does NOT mean that the surface of the earth is higher than in the past. What is actually happening is that these ...
PMar's user avatar
  • 51
5 votes

Can there be ice in the core because of pressure?

The answer is maybe -- if you are looking deep in the mantle rather than in the core, and if you are prepared to accept "superionic" ice in which the molecular structure of water has broken ...
Oscar Lanzi's user avatar
  • 3,926
4 votes

Why is the core of the earth thought to be iron rather than metallic oxygen?

1) The density of the core approximately matches that of high pressure Ni-Fe, but is way denser than solid oxygen (roughly 1.4). 2) If the core was oxygen then the overall elemental abundance of the ...
Gordon Stanger's user avatar
4 votes

How much would a nine inch slice of the Earth's inner core weigh?

An oddly specific question, but quite straightforward to calculate. Let's start by calculating the volume of your slice. I'm taking values for the inner core's physical characteristics from this ...
Pont's user avatar
  • 5,429
4 votes

How much of the Earth's heat is caused by the hot centre?

Given the insulating effect of 6370 km of rock (the average radius of the Earth) & its low thermal conductivity, if the temperature at the center of the earth was 18 °C it contribution to warming ...
Fred's user avatar
  • 24.7k
4 votes

Why is the core of Earth in a reduced state? ($\text{Fe}$ and $\text{Ni}$)

Because there wasn't enough oxygen to oxidise all of it. There is only so much oxygen on Earth. Most of it went to oxidise the elements that have higher affinities to oxygen: silicon, magnesium, ...
Gimelist's user avatar
  • 23.1k
4 votes

Do there exist reasonable numbers on the density/radius/mass of the various geological layers of the Earth?

One model that will help you is the admittedly dated (1981) Preliminary Reference Earth Model. It provides density models for the inner and outer core as functions of distance from the center of the ...
David Hammen's user avatar
  • 23.7k
4 votes

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?

As the comments suggest, there probably is no one factor, but a big one seems to be the gas and ice giants took most of the carbon away. In our Solar System as a whole, the primordial nebula had ...
Oscar Lanzi's user avatar
  • 3,926
3 votes

How Can We Establish Precisely What Earth's Core is Made Of?

No, simply because we cannot access it and the methods for understanding it are essentially indirect geochemical and geophysical measurements (mostly experimental petrology and wave propagation ...
Matheus's user avatar
  • 348
3 votes

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

The earth would be dead without a molten core. There would be no volcanoes, earthquakes etc no plate tectonics. Any material eroded from mountains would eventually end up at the bottom of the sea, and ...
Jason Farmer's user avatar
3 votes

What if we detonated the entire worlds nuclear supply in the center of the earth?

To add to David Hammen's answer. Earth is big. I hate to use the words "really really big" cause there are things much bigger, like the sun, but Earth is quite large. Imagine what would happen if ...
userLTK's user avatar
  • 5,867
3 votes

Why doesn't the Earth's outer core dissolve into the mantle?

This is an interesting question that is maybe a little misguided. Instead of answering your question directly I'd like to draw your attention to some things that might get you to rethink your ...
g.z.'s user avatar
  • 380
3 votes

Why the "Mission to Earth’s core" proposal suggests using liquid iron instead of lead?

I've already commented on this before here. This will not work regardless of whether this is iron or lead or anything else. The fact that it was published in Nature does not mean it is true, always ...
Gimelist's user avatar
  • 23.1k

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