星系与宇宙
Galaxies and the universe
描述宇宙的尺度，包括星系的结构、太阳在银河系中的位置，以及用光年作为距离单位；并理解为什么太空探索需要极其漫长的时间尺度。
Describe the scale of the universe, including the structure of galaxies, the position of the Sun in the Milky Way, and the use of light years as a unit of distance, and appreciate why space exploration requires enormous timescales
学习证据 / Evidence
- 将光年定义为光在一年内传播的距离。
- 描述星系的结构，并指出太阳是银河系中的一颗恒星。
- 比较太阳系内的距离与恒星之间、星系之间的距离，并用合适的单位来表示这些距离。
- Defines a light year as the distance light travels in one year
- Describes the structure of a galaxy and states that the Sun is a star in the Milky Way galaxy
- Compares the distances within the solar system with the distances between stars and between galaxies, expressing them in appropriate units
评估问题 / Assessment
如果{{name}}听说一颗恒星距我们400光年，他们能解释光年是什么意思、这个距离大概有多远，以及为什么用目前的航天器永远无法到达那里吗？
If {{name}} heard that a star is 400 light years away, could they explain what a light year means, roughly how far that is, and why we will never be able to visit it with current spacecraft?