The Eddington Mission

The Eddington mission was given full approval by the European Space Agencyon the 23rd May 2002, as part of the new `Cosmic Vision' Science programme, with launch scheduled for 2007/8. Its twin scienceobjectives are asteroseismology and planet finding.In its current design it consists of 4 × 60 cm folded Schmidt telescopes, eachwith 6° × 6° field of view and its own CCD array camera.The current observing plan is to spend 2 years primarily devoted to asteroseismologywith 1–3 months on different target fields monitoring up to 50,000 stars per field,and 3 years continuously on asingle target field monitoring upwards of 100,000 stars as required for planetsearching. The asteroseismic goal is to be able to detect oscillationsfrequencies with a precision 0.1–0.3 Hz.     

太阳系探测的进展与比较行星学的主要科学问题

回顾了太阳系的探测历程,综合分析了太阳系探测的发展趋势。未来的太阳系探测将以月球与火星探测为主线,适度开展太阳系其他行星及其卫星、小行星和彗星的考察性探测。21世纪将是全面探测太阳系并为人类社会长期可持续发展服务的新时代。随着太阳系探测的进展,通过系统比较地球与类地行星的大气层与水体的形成演化过程、地形地貌与地质构造特征、岩石类型、热历史与内部结构等方面的共性与特性研究,表明行星的质量大小和行星与太阳的距离的相互耦合,制约了行星的形成和演化的复杂过程。比较行星学已成为指导太阳系探测的科学理论体系。     

The evolution of planets. Venus as the Earth’s probable future

The general evolution of planets in the Solar System is discussed with a focus on the structure and history of Venus compared with the Earth. The history of the planets of the terrestrial group has been similar and included at least six correlated stages. Many common features the terrestrial planets shared in their early and late evolution have been due to their common origin from the protoplanetary gas-and-dust nebula and plume magmatism widespread on all the planets of the terrestrial group. The characteristic features of the structure and evolution of Venus are most brightly manifested in the specific composition of its atmosphere and of plume magmatism. Venus, with its surface as hot as 450 °C and the near-surface pressure of 92-93 bars, has a hot and dense atmosphere 93 times that of the Earth in mass. Most of its atmospheric mass (99%) belongs to the 65-km thick troposphere consisting of CO₂ (96.5%) and N₂ (3.5%). The upper troposphere includes a 25-30 km thick cloud layer composed mainly of sulfuric acid droplets, water vapor, and SO₂. At a height of 49.58 km, the clouds approach the conditions of the terrestrial surface and might be hospitable to bacterial life. Volcanism, the most active and widespread process of Venusian geology, maintains continuous SO₂ emission. There are diverse volcanic edifices on Venus, which are most often large and are similar to the Earth’s plume-related volcanoes. The evolution before 1 Ga, as well as the share and the role of alkaline rocks and carbonatites among its volcanics, are among the most debatable issues about Venus. Being located closer to the Sun, Venus cooled down more slowly and less intensely than the Earth after the primary accretion. In the Proterozoic, it began heating and reached its present state at ~ 1 or 2 Ga. In the future, as the Sun becomes a red giant, the Earth is predicted to begin heating up in 500-600 Myr to reach the temperature of present Venus in about 1.5 Gyr.     

行星(月球)自转监测望远镜的原理样机地面验证实验

类地行星(月球)自转监测望远镜的科学目标是在行星(月球)表面现场测量行星(月球)自转并研究其内部结构和物理性质.为了验证全新的观测原理和资料处理方法,项目团队设计制造了一套原理样机,在一台商用天文望远镜的光路前端增加3面反射镜组,使其具有同时观测3个视场的能力.自2017年起在地面上开展了观测实验,获得了混合有3视场星象的图像.通过计算星象在前后图像上的位移实现了归属视场识别,使得观测效果与分视场独立观测等同,证明了用一台设备同时观测多视场的可行性.处理图像并通过3个视场中心的指向变化归算地球自转轴的空间指向,与理论值比较偏差平均约1′′,证明了观测原理和数据处理方法有效.对各种观测误差来源进行了分析,包含大气折射、仪器热稳定性和光学分辨能力的影响等,指出采用更长焦距的望远镜可以提高空间分辨率,优化形变控制可以提高观测稳定性.改进多视场同时观测中的光学设计也有助于精度的提高.     

行星构造:寻求地球演化的踪迹

地质构造是记录地球内、外动力地质作用过程的标志.和地球相似,太阳系其他天体上也发育丰富的地质构造.以研究天体表面的地质构造及其动力学机制为目的的"行星构造学"是建立在构造地质学、遥感地质学和地球物理学等学科基础上的一门新兴前沿学科.由于天体的大小、组分和轨道位置不同,表面构造特征及其形成机制各异.对比研究地球和其他天体...