Lunar Crustal Magnetic Anomalies:

The Intersection of Space Plasmas and Geology

月殼磁異常：空間等離子體與地質學的交叉

主講人：David T. Blewett研究員

Johns Hopkins University Applied Physics Lab, USA

時間：2017年8月31日，上午10:00 – 11:30

地點：遙感樓517會議室

摘要：Strange and beautiful bright markings known as lunar swirls are found in many locations on the lunar surface. The most famous of these is the Reiner Gamma swirl in Oceanus Procellarum, on the western nearside. It has been known since the late 1970's that lunar swirls are correlated with areas of magnetized crustal rocks, although the relationship between the swirls and the magnetic anomalies is not clear. There are several hypotheses for the formation of the swirls. One idea is modification of the surface by a comet impact. Other concepts involve interaction of the solar wind with the crustal magnetic fields. The presence of the magnetic anomaly may shield the surface from sputtering and implantation by solar wind ions, causing abnormal conditions of space weathering. Thus, the swirls are a natural laboratory for the study of space weathering and planetary magnetism. I will review the characteristics of lunar swirls, examine their relationship with magnetic anomalies, and discuss recent evidence from spacecraft that sheds light on the formation of these enigmatic features.

報告人簡介：David T. Blewett is a member of the Principal Professional Staff in the Planetary Exploration Group at the Johns Hopkins University Applied Physics Laboratory in Maryland, USA. He was a member of the science team for the NASAMESSENGERMercury orbiter mission. He was also a member of theDawnscience team for the Vesta phase of the mission. His research interests are planetary surface processes, space weathering, remote sensing, and reflectance spectroscopy. He received a bachelor's degree in astronomy and astrophysics from the University of Pennsylvania, and master's and Ph.D. degrees (geology and geophysics) from the University of Hawaii.