Friday, May 4, 2018, 3pm
Location: Planetary Hall Room 212

Prabal Saxena
NASA Goddard Space Flight Center
Greenbelt, Maryland

The History of the Sun is Probably Buried in the Lunar Crust: The Story of Sodium

Abstract

While the Moon and Earth are similar in terms of composition, there exist variations in the abundance of certain elements among the two. These differences are a likely consequence of differing physical evolution of the two bodies over the solar system's history. Our past and current modeling efforts indicate that a significant fraction of the initial sodium budget of the Moon may have been depleted and transported from the lunar surface since the Moon's formation. The dominant driver of this loss was likely increased solar activity from the young Sun.  Importantly, this period of greatest solar activity occurred at the same time as the greatest impact frequency on the lunar surface, which created and churned a lunar regolith that recorded this changing solar activity.  Using profiles of sodium abundances from lunar crustal samples may thus serve as a powerful tool towards exploring conditions on the Moon's surface throughout solar system history.