r/theydidthemath • u/Kioga101 • 1d ago
[REQUEST] How long would it take for an average island to fall from sea level to the center of the Earth?
I was reading a fiction book (One Piece), and a certain situation that happens WAY LATE into the story intrigued me, and thinking about what could have happened led me to make this weird question.
If there was a hole big enough for the mass and area of an entire island (average) to fall through to the center of the Earth, considering drag in either water or air or magma, how long would it take? Because whenever I search it up, the quickest answer always discounts any resistance from any fluid at all, and example results that do take it into account wouldn't translate well into this particular question.
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u/jericho 1d ago
Well, an island wouldn’t fall through magma, islands aren’t dense enough. And if we wave our hands and make it dense enough, the question just becomes ‘how dense?’ . If it was neutron star dense, it would basically free fall, magma be damned. In that case, 21 minutes.
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u/Varlex 1d ago
Well, an island wouldn’t fall through magma, islands aren’t dense enough.
Why do you think so xD.
Just think about what islands really are and rethink your comment.
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u/jericho 1d ago
Density: The average density of continental crust is approximately 2.7 g/cm3.
Comparison to Oceanic Crust: Oceanic crust, composed of basalt, is denser (around 3.0 g/cm3) due to its higher content of iron and magnesium.
Comparison to Mantle: The mantle, which lies beneath the crust, is even denser than oceanic crust, with an average density of around 3.3 g/cm3.
Am I missing something?
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u/Varlex 1d ago
But he was talking about a hole.
Magma has a density of 2,4-2,9 g/cm³.
Anyway, the whole question is useless anyway.
No "island" will ever be sunk to the core. It will be melted first.
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u/Varlex 1d ago
Islands aren't floating around (in 99% of the cases). They are just at the top of an underwater mountain.
Also, it's not possible to have empty holes in the inner core of the earth.
Every hole is filled with magma. If something would exist, it would just melt before everything else happens.
Finally: fiction is fiction.
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u/Kioga101 12h ago
Thank you. I will never try to imagine anything other than the most realistic situation ever again.
No more circular cows. No more ignoring any little contributor to a number. I am a changed person now.
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