Imagining Other Earths

所在平台: Coursera

课程主页: https://www.coursera.org/learn/life-on-other-planets

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课程简介

课程名称：想象其他地球 课程概述：我们是否孤单？本课程介绍了天文学、生物学和行星科学的核心概念，使学生能够科学地推测这个深刻的问题，并创造自己的太阳系。所有课程功能均免费提供，完成课程后不提供证书。 课程大纲： 第1部分：生命是什么？ 本讲将介绍定义生命的不同方法，这是我们搜索生命的必要步骤。同时介绍生物化学的基本构建块。通过检测生命的副产品（如甲烷）来发现生命的方法，并讨论在火星上寻找生命的努力。 第2部分：行星大气 本讲首先介绍气体、液体和固体的基本物理学，然后阐述气体压力和引力之间的平衡如何塑造行星大气结构。 第3部分：月球 通过研究月球的特性，我们不仅了解它的历史，还了解地球的形成历史。本讲讨论了陨石坑的物理学以及地球与月球之间的潮汐相互作用，最后应用潮汐物理学来探讨M星周围行星的特性。 第4部分：开普勒与过境 过境现象在天文学中已有400多年的重要性。本讲描述了金星的过境及其如何用于测量太阳系的大小。随后讨论了美国宇航局开普勒任务如何观察行星过境以及其观察结果如何影响我们对系外行星系统特性的理解。 第5部分：恒星演化 像行星一样，恒星的结构也受引力与压力之间平衡的影响。核聚变，作为恒星内部的能量源，将氢转化为更重的元素。本讲介绍了这些概念，并展示核燃烧如何推动恒星的演化。 第6部分：地球的形成与水的起源 本讲讨论恒星与行星形成的物理学。由于角动量守恒， collapsing gas clouds形成盘状结构，随后分裂形成行星。我们观察到丰富的行星系统多样性，这表明行星具有更广泛的特性。 第7部分：极端微生物 极端微生物是能够在极端环境中繁衍生存的生命形式，这些环境可能是高温、低温、高酸度，甚至强辐射。本讲描述了一些令人着迷的生命形式，包括黄石公园的细菌垫和地衣短杆菌，这是一种地球上最坚韧的生物。这些极端微生物有助于我们理解天体生物学。 第8部分：可居住区、费米悖论与SETI 最后一讲讨论在银河系中寻找技术先进生命的工作。我们描述了“费米悖论”：如果技术先进的生命很常见，那么它们早已在银河系中传播。因此，我们应该早就遇到生命。最后，本讲提出了“他们为什么不来？”的思考。

课程大纲

Part: 1

Title:What is Life?

Description:This lecture introduces different approaches to defining life, a necessary step if we are going to search for life. We then introduce the basic building blocks of biochemistry. One potential way of detecting life is through its byproducts like Methane. We discuss efforts to discuss life on Mars.

Part: 2

Title:Planetary Atmospheres

Description:This lecture begins by introducing the basic physics of gases, liquid and solids. The lecture then describes how the balance between gas pressure and gravity shapes the structure of planetary atmospheres.

Part: 3

Title:The Moon

Description:By studying the properties of the Moon, we learn not only about its history but about the formation history of the Earth. This lecture discusses the physics of craters and the tidal interactions between the Earth and the Moon. We then apply the physics of tides to see how it shapes the properties of planets around M stars.

Part: 4

Title:Kepler and Transits

Description:Transits have been an important event for astronomy for over 400 years. This lecture describes the transit of Venus and how it was used to measure the size of our Solar System. This lecture then discusses how NASA’s Kepler mission observes planetary transits and how its observations have shaped our understanding of the properties of extrasolar planetary systems.

Part: 5

Title: Stellar Evolution

Description:Like planets, the structure of stars are shaped by the balance between gravity and pressure. Nuclear fusion, the energy source at the star’s interior, converts Hydrogen to heavier elements. This lecture introduces these concepts and shows how nuclear burning drives the evolution of stars.

Part: 6

Title:Formation of the Earth and the Origin of Water

Description:This lecture discusses the physics of star and planet formation. Because of the conservation of angular momentum, collapsing gas clouds form disks that then fragment to eventually form planets. We observe a tremendous diversity of planetary systems which implies that planets, unlike Stars, have a much wider range of properties.

Part: 7

Title:Extremophiles

Description:Extremophiles are life forms that flourish in extreme environments—regions of very high (or low) temperatures, acidities, and even intense radioactivity. The lecture describes some of these fascinating life forms including the bacterial mats of Yellowstone and Deinococcus Radiodurans, the toughest creature on Earth. These extremophiles inform our understanding of astrobiology.

Part: 8

Title:Habitable Zone, Fermi Paradox & SETI

Description:The final lecture discusses the search for technologically advanced life in the Galaxy. We describe the “Fermi Paradox”: if technologically advanced life is common, then it would have long ago spread through the Galaxy. Thus, we might have expected to have already encountered life. This lecture ends by contemplating “why aren’t they here?”

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