Mercury’s Exosphere: A Brief Overview

One of the primary science goals of MESSENGER is to study Mercury's very thin atmosphere, or exosphere. Although observations of the exosphere from orbit have begun, these data must be carefully calibrated, and analysis is still underway. In the meantime, go online to Highlights-of-Mercury-Science.html for a primer on Mercury's exosphere: what it is, how we observe it, and why it is important.