They gloss over a lot with the term "crustal differentiation". This page (intro of a book) explains a bit about how magma gets separated into silicate-rich and -poor fractions: <a href="https://www.sciencedirect.com/topics/earth-and-planetary-sciences/magmatic-differentiation" rel="nofollow">https://www.sciencedirect.com/topics/earth-and-planetary-sci...</a> .
"Earth is the only planet we know of with continents..." -- links to a paper comparing Earth with only the inner rocky planets of our own solar system and citing other planet's lack of water, and therefore granite.<p>I think that intro sentence is implying a lot more than the paper it cites is stating.<p>Paper cited: <a href="https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/GL010i011p01061" rel="nofollow">https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/GL01...</a>
If you like speculative fiction, John Brunner wrote very odd fiction about mobile and ultimately intelligent plants who come into being in a meteor rich planet, from water to land, to space..<p><a href="https://en.wikipedia.org/wiki/The_Crucible_of_Time" rel="nofollow">https://en.wikipedia.org/wiki/The_Crucible_of_Time</a>
The article mentions that other planets don't have continents, but isn't that an argument against this hypothesis? The same process of asteroid collisions would have happened there too.
Since we already know a pretty decent-sized meteor hit in the Yucatan, shouldn't we expect to see evidence of this process (at least starting to) happening there? I'm not certain what that evidence would look like, and maybe 65 million years is too short a time period?
We are on such a Goldilocks planet it isn’t even funny. Or life is so exquisitely tuned to optimize for earth’s conditions it isn’t even funny. Or both.<p>We see magnetic fields this strong on gas giants, but not on inner planets. I wonder too if we will find that some asteroid impacts and the formation of the moon didn’t goose up the magnetic flux of the core while they were at it. Maybe habitable zones only appear on tortured worlds, like earth and some of the moons of a Jupiter, because normal planets are just too boring, don’t have enough building blocks for life.