人教高中英语必修3课件：Unit 4　Astronomythe science of the stars4.1.pptxVIP

Unit4 Astronomy:thescienceofthestars 课标导航主题导读 Another “Earth” Spotted in Corner of Milky Way?????Another “Earth” which may hold liquid water and could sustain life has been spotted orbiting a distant sun in our galaxy.It is the first time that astronomers have observed a rocky planet that is the same size as our own “Goldilocks Zone”—an area that is neither too hot,nor too cold.The planet—named Kepler-186f—is 500 light years away and orbits a red star in our corner of the Milky Way.课标导航主题导读 The planet which is just 0.1 times bigger than the Earth,is at a distance from its sun where lakes,rivers or oceans on the surface will not freeze or boil away.Since liquid water is important to life on the Earth,many scientists believe the search for life out of the Earth should focus on planets where liquid water occurs.The size of the planet also means it has enough gravity to pull in gases like hydrogen and helium(氦) to form an atmosphere.Kepler-186f is orbiting at the outer edge of the habitable zone around its star,which could mean that any liquid surface water would be in danger of freezing.However,it is also slightly larger than the Earth,and so the hope would be that this would result in a thicker atmosphere that would make the surface warm enough to keep water liquid.课标导航主题导读 课标导航主题导读So far more than 3,800 possible planets have been detected by Kepler,but this is the first that is so much like the Earth.However it would be impossible to visit the planet to find out if it contained life.Not only is it 2,939 trillion miles away,the light we are seeing is 500 years old. 课标导航主题导读诱思探究 1.Do you believe there in another Earth in the universe?Why or why not?2.Would you be able to visit the planet to find out if there is life on it?Give your reasons.答案1.Different students have different opinions.2.Different students have different opinions. 课标导航主题导读Section Ⅰ　Warming Up,Pre-reading,Reading & Comprehending 基础导练文本感知知识精要基础导练Ⅰ.词汇拓展1.　　　　　　　 n.天文学→　　　　　　　 n.天文学家?答案astronomy;astronomer