专业英语5_Astrophysics.ppt

* * Astrophysics CosmologyNow we leap to the largest – stars and galaxies. These two extreme realms, elementary particles and the cosmos, are among the most intriguing(引起兴趣的) and exciting subjects in science.Use of the techniques and ideas of physics to study the heavens is often referred to as astrophysics. At the base of our present theoretical understanding of the universe is Einstein’s general theory of relativity and its theory of gravitation – stars 星体 galaxy [‘g?l?ksi] 星系,银河 cosmos [‘k?zm?s] 宇宙 astrophysics [?str??’fIzIks] 天体物理学 general theory of relativity 广义相对论 专 业 英 语 Physics English for in the large-scale structure of the universe, gravity is the dominant force. General relativity serves also as the foundation for modern cosmology, which is the study of the universe as a whole. Cosmology deals especially with the search for a theoretical framework to understand the observed universe, its origin, and its future. cosmology [k?z’m?l?d?i] 宇宙学 专 业 英 语 Physics English planet 行星 telescopic [telis’k?pik] 用望远镜看的 1 Stars and GalaxiesAccording to the ancients, the stars, except for the few that seemed to move (the planets), were fixed on a sphere. The universe was neatly self-contained, and we on Earth were at or near its center. But in the centuries following Galileo’s first telescopic observations of the heavens in 1610, our view of the universe has changed dramatically. 专 业 英 语 Physics EnglishWe no longer place ourselves at the center, and we view the universe as vastly larger. The distances involved are so great that we specify them in terms of the distance traveled (in a vacuum) by light in one year: 1 light-year (ly) = 9.47×1015 m.Besides light-year, in astrophysics, the following distance units are often used: Astronomical unit (AU) This is the mean radius of the Earth’s orbit around the Sun. 1 AU = 1.50 × 1011 m. light-year 光年 astronomical [?str?’n?mIk(?)l] unit(AU) 天文单位 专 业 英 语 Physics English Parsec (pc) This is the distance at which the m