landing in Mars it is like the landing of an invasion army. 2.Europa is extremely cold.Many signs show there might be an ocean below the surface of the planet. Para.11 1.SETI .each year. So far the scientists have not received any message or detected any signal from a civilization in other parts of the universe 2.The optimists.channel Those who are optimistic think that as time goes on,they will some day get the signal sent out by an alien civilization. Para.12 l.Pay attention to the“if not'”pattern Eg.The breakthrough is many years,if not decades,away. We may well be alone in this galaxy if not in the universe Para.13. 1.the reasons which sustain the search for alien organism:(1)the universe looks to be a place suitable for the existence of life:(2)if that is the case,life will give out signs of its existence and these can be detected 2.life radiates information about itself:Life snds out signals of its existence,the signal being light or heat or electromagnetic waves or other manifestations. Para.14 1.Why would contact with an alien civilization be an epochal and culturally challenging event? It would be epochal,that is to say,it ushers in an entirely new period in human history because that would be the first time for human beings to have direct communication with civilization on another planet in the universe.It would be culturally challenging because alien civilization might be totally different from anything in human history and night be much superior to our civilization. 2.The long process .true cosmic context The long process of regarding this human inhabited world as only one example of the universe humming with life.Originally we regard our world as the only one in the universe which inhabited by intelligent humans,but we need to change our view andlanding in Mars,it is like the landing of an invasion army. 2. Europa is extremely cold.Many signs show there might be an ocean below the surface of the planet. Para. 11 1. SETI . each year. So far ,the scientists have not received any message or detected any signal from a civilization in other parts of the universe. 2. The optimists . channel Those who are optimistic think that as time goes on,they will some day get the signal sent out by an alien civilization. Para. 12 1. Pay attention to the “if not” pattern: Eg. The breakthrough is many years,if not decades,away. We may well be alone in this galaxy if not in the universe. Para. 13. 1. the reasons which sustain the search for alien organism: (1) the universe looks to be a place suitable for the existence of life; (2) if that is the case,life will give out signs of its existence and these can be detected 2. life radiates information about itself: Life sends out signals of its existence,the signal being light or heat or electromagnetic waves or other manifestations. Para. 14 1. Why would contact with an alien civilization be an epochal and culturally challenging event? It would be epochal,that is to say,it ushers in an entirely new period in human history because that would be the first time for human beings to have direct communi cation with civilization on another planet in the universe.It would be culturally challenging because alien civilization might be totally different from anything in human history and night be much superior to our civilization. 2. The long process . true cosmic context. The long process of regarding this human inhabited world as only one example of the universe humming with life.Originally we regard our world as the only one in the universe which inhabited by intelligent humans,but we need to change our view and