IBT阅读真经: 一闪一闪亮晶晶, 满天都是小星星
来自我不喜欢考试-知识库
一天老师问小明说，
为什麼飞机撞不到天上的星星呢。
小明想说：这麼容易的天文常识就想要考倒我。
小明回答：因为星星会闪。
冷到了…
[编辑] Astronomy（天文学）
[编辑] 星体的形成：(06.07.29)
how stars originated. first son exploded to dust and gas, stars accumulate the gas and crust , that's why some planets are alike. other planet differ...
上课补充知识：
- STARS
- A star develops from a giant, slowly rotating cloud that consists almost entirely of the chemical elements hydrogen and helium.
- Due to the force of its own gravity, the cloud begins to collapse inward, thereby becoming smaller. As the cloud shrinks, it rotates more and more rapidly, just as spinning ice skaters turn more rapidly when they pull in their arms.
- Stars are balls of gas that shine or used to shine because of nuclear fusion in their cores.
- The most familiar star is the Sun. The nuclear fusion in stars produces a force that pushes the material in a star outward. However, the gravitational attraction of the star’s material for itself pulls the material inward.
- A star can remain stable as long as the outward pressure and gravitational force balance.
- Astronomers study stars by measuring their brightness or, with more difficulty, their distances from Earth. They measure the “color” of a star—the differences in the star’s brightness from one part of the spectrum to another—to determine its temperature.
- They also study the spectrum of a star’s light to determine not only the temperature, but also the chemical makeup of the star’s outer layers.
- Stellar evolution
- The Sun is a type of star known as a main-sequence star. Eventually, main-sequence stars such as the Sun swell into giant stars and then evolve into tiny, dense, white dwarf stars. Main-sequence stars and giants have a role in the behavior of most variable stars and novas. A star much more massive than the Sun will become a supergiant star, then explode as a supernova. A supernova may leave behind a neutron star or a black hole.
[编辑] 引用
康老師的Blog[1]
