13 votes

Why is Earth's Core Iron?

I can only answer the question of why is it mostly iron. Not too sure of the magnetic properties of iron versus nickel. As said in another answer, there is simply much more iron around than nickel. ...
Gimelist's user avatar
  • 23.1k
12 votes
Accepted

Pangaea - Why did all the land mass form in one area?

The formation and break up of supercontinents have happened throughout Earth's history in almost a cyclical manner. There may have been many others supercontinents before Pangaea and the total number ...
arkaia's user avatar
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8 votes
Accepted

Why is there so much more silicon than carbon in the Earth's crust?

So where did it go? Carbon was never there (or here) to begin with. You need to look at this from the opposite way. By asking "where did it go" you assuming the Earth was here first, with carbon, and ...
Gimelist's user avatar
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8 votes

Do scientists ever make rock vapor in a laboratory? If so, is it ever used to study planetary or lunar formation?

Not quite "rock vapour", but scientists do study gas-rock interactions. Some of that is used to understand processes forming in the moon. For example, this paper looked at volatile metals (...
Gimelist's user avatar
  • 23.1k
7 votes

Why is Earth's Core Iron?

The main reason that there is more iron than nickel in the Earth's core, and in the universe generally, is that Nickel-56 beta-decays to Iron-56 (via cobalt-56). Much nickel-56 forms in Asymptotic ...
DavePhD's user avatar
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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
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5 votes

How did hydrogen make its way into proto-Earth?

The article you've shared doesn't assume the hydrogen in the core came from the hydrogen in the protosolar nebula. In fact it ignores all modern literature on planet formation, and just cites lab ...
AtmosphericPrisonEscape's user avatar
5 votes

Were all of Earth's minerals created before Earth's formation, during, or after?

This is a very interesting topic that in the past several years has reached the spotlight because of the work of Robert Hazen on the concept of "mineral evolution". Minerals are basically just ...
Gimelist's user avatar
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4 votes
Accepted

Why does the Earth's crust have more aluminum than magnesium while the Sun has more magnesium than aluminum?

On the earth as a whole, there is much more magnesium than aluminium. Your question is why, specifically in the crust, there is more aluminium than magnesium. The reason is that Mg is a compatible ...
Gimelist's user avatar
  • 23.1k
4 votes

Is the giant impact hypothesis still alive?

The giant impact hypothesis was not formulated to address the issue of how the Earth acquired its waters. At the time the giant impact hypothesis was formulated, the dominant theory for how the Earth ...
David Hammen's user avatar
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4 votes
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Plate Tectonics vs Gravity for Creating Highs and Lows

I think this question is less intuitively obvious than it appears. and I like @Universal_learner 's answer. I thought I'd give a different approach to the question. Earth is the only object in the ...
userLTK's user avatar
  • 5,847
3 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?

When they are molten these metals dissolve within each other - ie they are in solution. Convection and diffusion will disperse and mix them; convection and accompanying turbulence mixes them at large ...
Ken Fabian's user avatar
  • 2,056
2 votes

Why is Venus so cracked?

I found the picture with a small write up on a JPL site. It's a picture of the Aine Corona with pancake domes. P-38340 MGN-48 5/21/91 This Magellan radar image shows a region approximately ...
Fred's user avatar
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2 votes
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How can radiometric dating of meteorites determine the age of the earth? Wouldn't this only determine the age of the decaying nuclide in each rock?

Many of your questions are answered in this question and associated answers: Why is Earth's age given by dating meteorites rather than its own rocks? To add to some of your other questions: ...
Gimelist's user avatar
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1 vote

Was Earth completely covered in Oceans prior to the onset of plate tectonics?

This all comes down to a single issue. Define plate tectonics. There are several ways it can be defined which is why estimates of when it started vary by more than half the age of the planet. At the ...
John's user avatar
  • 6,906
1 vote
Accepted

Geological Differentiation: variables and size requirement

Not really. Assuming even minor igneous bodies differentiate (stocks), and that differentiation is basically a process of decantation of the solid magmatic phase (a process known as fractional ...
Matheus's user avatar
  • 348
1 vote

Were all of Earth's minerals created before Earth's formation, during, or after?

Minerals are naturally occurring chemical compounds composed of elements. Much of these elements were originally deposited with the earth saw formed. However, meteorites and asteroids have carried new ...
Earth Science Expatriate's user avatar
1 vote

Pangaea - Why did all the land mass form in one area?

Just to add, cause I don't see it in the answers above. Continents are no heavier than oceans. As far as the Earth is concerned, they weigh about the same and they drift according to the flow of ...
userLTK's user avatar
  • 5,847
1 vote
Accepted

Why is "at least a small tilt" between rotation and magnetic axis required by models of magnetic field formation?

It sounds like Ingersoll was referring to Cowling's Theorem -- that flow in a planet's core that is purely symmetric around the planet's rotation axis (that would give a magnetic dipole field with no ...
WJB's user avatar
  • 921
1 vote

Why is "at least a small tilt" between rotation and magnetic axis required by models of magnetic field formation?

"Tilt" is a consequence of a convecting metal inner core....not a "necessity". In the earth's case, that tilt has, over time, wandered from 0 to 180 degrees, sometimes with some temporal regularity, ...
Knob Scratcher's user avatar

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