MESSENGER's flight through Mercury's "tail"

This animation shows an artist's conception of Mercury's magnetosphere at the time of the MESSENGER flyby. The graphs at the bottom show observations made by the Fast Imaging Plasma Spectrometer (FIPS) instrument as the spacecraft flew past the night side of Mercury. The top plot depicts low-energy plasma -- which comes from the solar wind -- and the bottom plot shows heavy ion intensities associated with the planet.