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canineraytube t1_jddaj5o wrote

Reply to comment by CrustalTrudger in Does the metal in the solid core of a rocky planet have any special properties? by VillagerNo4

>Actually, no.

But the four densest elements—osmium, iridium, platinum, and rhenium—are all in fact highly siderophilic. So wouldn’t we still expect a high concentration of those to be found at the very center of the inner core?

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Global_Lavishness_88 t1_jddh0ga wrote

I think that's because they are very rare and there isn't a lot of them

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Blank_bill t1_jden5e6 wrote

Is the reason they are rare is that they are Siderophilic ?

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aphilsphan t1_jdexzed wrote

Their abundance in the initial cloud that the solar system formed from would be tied to how likely they are to form during a supernova. That’s nuclear physics not chemistry.

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KaiserTom t1_jdgdegp wrote

Also a question of how astrological bodies are formed. There's a large amount of those elements that are easily accessible in asteroids. If there was ever a reason to asteroid mine, it would be for those elements. Iron being pretty prolific in general and in asteroids probably does go well with their siderophilic properties, which is probably why we tend to find those elements in large amounts in asteroids.

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xrelaht t1_jdfzwzx wrote

I am not an expert, but my understanding is this is at least partially correct. As mentioned, asteroids are differentiated core fragments, and impact craters (eg Chicxulub) are sometimes dated by the iridium distribution in geological layers. The iridium comes from the asteroid. I don’t know why iridium gets all the press over other other platinum group elements, but a cursory search suggests they’re also used for impact dating. https://physicsworld.com/a/iridium-in-undersea-crater-confirms-asteroid-wiped-out-the-dinosaurs/

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