Stochastic late accretion to Earth, the Moon, and Mars

William F. Bottke, Richard J. Walker, James M.D. Day, David Nesvorny, Linda Elkins-Tanton

Research output: Contribution to journalArticlepeer-review

172 Scopus citations


Core formation should have stripped the terrestrial, lunar, and martian mantles of highly siderophile elements (HSEs). Instead, each world has disparate, yet elevated HSE abundances. Late accretion may offer a solution, provided that ≥0.5% Earth masses of broadly chondritic planetesimals reach Earth's mantle and that ∼10 and ∼1200 times less mass goes to Mars and the Moon, respectively. We show that leftover planetesimal populations dominated by massive projectiles can explain these additions, with our inferred size distribution matching those derived from the inner asteroid belt, ancient martian impact basins, and planetary accretion models. The largest late terrestrial impactors, at 2500 to 3000 kilometers in diameter, potentially modified Earth's obliquity by ∼10°, whereas those for the Moon, at ∼250 to 300 kilometers, may have delivered water to its mantle.

Original languageEnglish (US)
Pages (from-to)1527-1530
Number of pages4
Issue number6010
StatePublished - Dec 10 2010
Externally publishedYes

ASJC Scopus subject areas

  • General


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