WARC DISCOVERIES

Early histories of the Earth and Moon: Similar, but different

It is commonly accepted that the Moon formed through collision between the Earth and an unknown planetary body very early in the history of the Solar System, but the mass of material that was transferred from this unknown body to the Earth and Moon remains unclear. WARC researchers Mike Spicuzza and John Valley have studied samples from the Moon for the relative amounts of three isotopes of oxygen, ¹⁶O, ¹⁷O, and ¹⁸O, which previous studies have shown are diagnostic of the location of condensation within the Solar Nebula, as well as identification of “extrasolar” material. Their studies, which have been published in the journal Earth and Planetary Science Letters, suggest that the unknown impactor that hit the Earth probably came from a similar orbit as the Earth’s, or that the Moon may contain a much smaller proportion of material from the impactor relative to the Earth. Understanding the early history of the Earth-Moon system has astrobiological implications as new exploration efforts are aimed at the Moon, as well as the possibility that a record of early life on Mars or Earth may lie in the meteorite record that has been preserved on the Moon’s surface.

Citation:
Spicuzza, MJ, Day, JMD, Taylor, LA, and Valley, JW (2007) Oxygen isotope constraints on the origin and differentiation of the Moon.  Earth and Planetary Science Letters 253:254-265. A PDF copy of the paper can be found here. 

Posted January 11, 2008