内容简介：

       Astrobiology is the study of the origins of biology, the distribution of biology in the cosmos and the search for extraterrestrial intelligence. Exploration of both the origins of life and the habitability of other worlds is performed by the study of planetary bodies such as planets, asteroids, comets and planetary satellites. Fragments of those bodies as planetary materials provide a forensic account of the formation and evolution of those bodies revealing for instance, the action of water on Mars and evolution of abiotic organic material (OM) in the early Solar System.
       Meteorites provide the highest sample yield of planetary materials. Prebiotic chemicals from the early Solar System are found in chondritic meteorites. The major form of OM is insoluble organic matter (IOM). Aqueous alteration and mild thermal metamorphism recorded in the OM describe its geophysical and geochemical evolution on early planetesimals. Abiotic chondritic organics also display some geochemical affinities with natural OM from Earth such as shale kerogen and early microfossils. The delivery of OM to the surface of Mars is evident; its surface peppered by impact craters caused by fragments of early planetesimals. The need to therefore disambiguate between biogenetic OM and chondritic OM on the surface of Mars is paramount in the search for biomarkers from other worlds.
       In this presentation we will delve into the action of water on Mars, the organic delivery to Mars and the prebiotic chemistry of the early Solar System from a planetary materials perspective.

报告时间：2019年5月30日（周四）下午2:30
报告地点：闻天南楼211会议室
报告人简介：

       Hitesh Changela 博士出生于英国。本科毕业于物理学方向，硕士阶段在伦敦大学国王学院、加州大学伯克利分校从事生物、纳米和X射线光子学研究。2011年博士毕业于英国莱斯特大学，利用电子探针和X射线技术开展火星Nakhlites、星尘号返回的彗星样品研究。之后在美国海军研究实验室、乔治华盛顿大学、新墨西哥大学开展博士后阶段研究。因在星尘号星际颗粒样品研究中的出色表现，被授予NASAGroup Achievement Award。目前在中科院地质与地球物理研究所，从事太阳系早期有机物和火星样品研究。
       他利用各种尖端分析方法，如纳米离子探针、同步辐射X射线吸收精细结构分析等，重点研究碳质球粒中纳米级有机物，来认识太阳系早期物质中有机物的分布和成因，探索生命的起源。