| 课程号 |
00430170 |
学分 |
2 |
| 英文名称 |
An Introduction to Distance Measurement in Astronomy |
| 先修课程 |
Stellar structure and evolution, galaxies, cosmology (minimum 2 years of completed undergraduate coursework in astrophysics) |
| 中文简介 |
在天体物理研究中，距离测量起着关键性的作用： 不知道准确的天体距离，我们就无法得知这个天体的亮度、大小，甚至不知道它是何时产生的（对远距离天体来说）。但是，如何测量天体的距离却是一个很具有挑战性的工作：直到1838年，科学家才第一次测量出另一颗恒星离我们的距离，而对于离我们最近的河外星系，则是到了二十世纪50年代才首次得出准确的距离。这并不令人感到惊讶：我们虽然可以对太阳系中的天体进行精确的距离测量，可一旦超出太阳系，大部分距离的测量依赖于推论出的所研究天体的物理性质，因此这种测量具有根本上的不确定性。而想要研究关于整个宇宙的年龄和大小以及其未来的演化这种最基本的问题却又要求我们必须对星系尺度或更远天体的距离进行准确测量。从这一似乎令人感到无望的起点，现代天文学家发展了各种测距方法，从常规的技术（如类似航海者使用的经纬仪）到奇特的手段（广义相对论中的光线偏折，微波背景辐射谱的振荡行为），从而引领我们从最近的恒星走向最遥远的星系。
本课程将用30个课时来带领学生进行一次宇宙航行，从太阳附近一直到宇宙边缘，途中，将探讨测量各种具有里程碑意义的距离时所使用的方法。我们将着重讲解各种方法的物理原理，引导学生欣赏并领会看似玄妙的现代科学技术是如何真正得以实施并得到自恰的结果。本课程旨在为学生提供一个对天文距离测量方法的全景式快览，不止是了解迄今为止所得到一些科学结果和最新进展，也包括对科学研究中曾遇到的各种陷阱以及结果中所含不确定性的讨论。尽管我们所关注的只是距离测量的技术，但它和天体物理学还有宇宙学的很多方面都有着十分密切的联系。我们的学习内容将会涉及所有类型的，包括单个、成对或处于星团中的恒星，他们的生命周期及爆炸式的结局；星系的恒星成分，动力学及演化；引力作用下星体光线的弯曲；宇宙的膨胀、几何以及演化历史。因此，这一课程不仅提供了有关距离测量的综合知识,同时展示了当今天体物理学的最新进展。
本课程的学习内容适合于高年级的物理学院本科生，其中对各类技术的详细介绍也可为研究生的科研工作提供一个参考。我们强烈鼓励学生踊跃提问并积极地参与讨论。学生的学习水平将通过集体讨论和课后作业的方式被定期评估。另外，每一位学生需要选择一个给定的课题然后进行详细的研究，并最终写出一篇3000字左右的论文。课程的期末成绩将由课后作业（40%）、论文（40%）以及课堂出勤率和讨论参与度（20%）共同构成。
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| 英文简介 |
Knowing the distance of an astrophysical object is key to understanding it: without an accurate distance, we do not know how bright it is, how large it is, or even (for long distances) when it existed. But astronomical distance measurement is a challenging task: we measured the first distance to another star as recently as 1838, and accurate distances to other galaxies – even the nearest – date only to the 1950s. This is not really surprising, since while we can determine highly accurate distances to objects in our Solar System, once we leave the immediate environment of our Sun, most distance measurements depend on inferred physical properties of the object in question, and are therefore fundamentally uncertain. At the same time, accurate distance measurements on scales of galaxies and beyond are crucial to get a handle on even the most basic questions related to the age and size of the Universe as a whole – and to its future evolution. Yet, from this unpromising starting point, modern astronomers have developed methods of measuring distances which can take us from the nearest star to the most distant galaxy, using techniques which vary from the mundane (the astronomical equivalent of the surveyor’s theodolite) to the exotic (the bending of light in general relativity, wiggles in the spectrum of the cosmic microwave background).
In this course we take the students on a journey from the solar neighbourhood to the edge of the Universe in 30 lecture hours, exploring on the way the various methods employed to define the milestones along the road. We will emphasise the physical basis of the methods, leading the students towards an appreciation of the somewhat surprising fact that modern techniques, however apparently esoteric, do actually work and give reasonably consistent results. We aim to provide a snapshot of the field of distance measurement, offering not only up-to-date results and an account of recent progress, but also full discussion of the pitfalls encountered and the uncertainties which remain. Although our focus is techniques of distance determination, this is intimately linked to many other aspects of astrophysics and cosmology. On our journey we shall encounter stars of all types, alone, in pairs and in clusters, their life cycles, and their explosive ends; the stellar content, dynamics, and evolution of galaxies; the gravitational bending of starlight; and the expansion, geometry and history of the Universe. As a result, this course will offer not only a comprehensive study of distance measurement, but a tour of many recent advances in astrophysics.
The intention is to present a level of detail appropriate for senior undergraduate students in the physical sciences. Where appropriate, more technical details will be discussed, making the course a useful reference for post-graduate students as well. Students are strongly encouraged to actively participate, by raising questions and contributing to discussions. Their understanding will be evaluated regularly through discussions and homework assignments. In addition, each student will explore a pre-assigned astronomy-related topic in detail, and write a 3000-word essay. The homework contributes 40% to the final grade, the essay will contribute 40% and class attendance and participation contribute 20%.
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| 开课院系 |
物理学院 |
| 通选课领域 |
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| 是否属于艺术与美育 |
否 |
| 平台课性质 |
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| 平台课类型 |
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| 授课语言 |
英文 |
| 教材 |
Galactic Dynamics,Binney & Tremaine,Princeton University Pres,1987；
An Introduction to Distance Measurement in Astronomy,Richard de Grijs,Wiley-Blackwell,2011；
Galactic Astronomy,Binney & Merrifield,Princeton University Press,1998；
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| 参考书 |
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| 教学大纲 |
The course “An Introduction to Distance Measurement in Astronomy” (天文测距介绍) is aimed at senior undergraduate and post-graduate students who have completed at least two years of coursework in astrophysics or related fields. The understanding of the students will be regularly evaluated through discussions and homework assignments. In addition, each student will explore a pre-assigned related topic in detail and write a 3000-word essay. The homework contributes 30% to the final grade, the essay will contribute 50%, and class attendance and participation contribute 20%.
The course will be taught in English, and all discussions and assignments will be in English. The final essay must be in English.
I propose to give this course for the first time during the spring semester of 2012 (I am unavailable during the autumn semester of 2011), for a minimum of 3–5 years. The lecture series will be organised as follows (following the outline of the textbook associated with the course):
Week 1: Introduction
Weeks 2–3: Local (mostly geometric) methods
Weeks 4–7: Stellar structure and evolution
Weeks 6–8: Galaxies
Weeks 9–11: Cosmology
Weeks 12–13: Statistics
Weeks 14–15: The future
课堂讲授
学生的学习水平将通过集体讨论和课后作业的方式被定期评估。另外，每一位学生需要选择一个给定的课题然后进行详细的研究，并最终写出一篇3000字左右的论文。课程的期末成绩将由课后作业（30%）、论文（50%）以及课堂出勤率和讨论参与度（20%）共同构成。
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| 教学评估 |
理查德：
学年度学期：16-17-1，课程班：天文测距导论1，课程推荐得分：4.69，教师推荐得分：4.38，课程得分分数段：90-95；
学年度学期：17-18-1，课程班：天文测距导论1，课程推荐得分：3.13，教师推荐得分：3.13，课程得分分数段：80及以下；
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