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I know atomic mass can be (over) simplified as the average mass of all isotopes of a given element weighted by the ratio of their natural occurrence. I also know that, as far as we know, refining relative atomic mass is a matter of finding new significant figures, not finding new isotopes. Are we reasonably sure these ratios won't change as we explore the universe?

As an over simplified example, do we have a reasonable certainty that 70% of the Calcium on Mars won't turn out to be Ca-41?


marked as duplicate by Curt F., Community Jun 22 '15 at 18:22

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  • $\begingroup$ Your question is equivalent to asking "is the isotopic abundance for the isotopes of all elements constant from planet to planet, star to star, galaxy to galaxy, eon to eon, etc" I think this stack exchange question is identical and has quality answers to boot: chemistry.stackexchange.com/questions/33056/… $\endgroup$ – Curt F. Jun 22 '15 at 18:21
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