Life in the future（Period 3　Listening and Speaking）

the characteristic temperature in the lower atmosphere is about 200 k, which is generally colder than the average daytime surface temperature (250 k).it decreases upward from the surface at about 1.5 k per vertical kilometer.unlike that of the earth, the total mass (and pressure) of the atmosphere experiences large seasonal variations, as carbon dioxide“snows out”at the winter pole.the annual variation of surface pressure was measured to be about 26 percent of the mean atmospheric pressure (7-8 millibars) at the lander sites, equivalent to some 7.9×1012 metric tons of carbon dioxide��.although the martian atmosphere is thin, it supports a variety of clouds.white clouds are water ice, while the“yellow”ones are dust storms that throw dust into the atmosphere to heights of 10 km (6 miles) or more.even in the absence of storms, the atmosphere is never clear of dust, which greatly affects atmospheric structure.

reference for teaching

exploring the planet marspeople on earth have always been interested in the planet mars.recently, that interest has increased because several successful spacecraft have been placed in orbit around mars.these include the american space agency’s mars global surveyor and mars odyssey and the european space agency’s mars express.

教學資源，完全免費，無須注冊，天天更新！" type="#_x0000_t75">perhaps the most exciting event took place on january third.that is when the first of two mars exploration vehicles successfully landed on the red planet.the first lander is named“spirit”.it came to rest in an area of mars named gusev crater.millions of people used their computers to link with nasa’s internet web site to see photographs sent back by spirit.on january fifteenth, nasa scientists told spirit to use its six wheels to move off the landing device.it did this successfully and rolled on to the surface of mars.excited nasa officials said spirit was now ready to begin its task of exploring the surface of the red planet.

教學資源，完全免費，無須注冊，天天更新！" type="#_x0000_t75">on january twentieth, scientists told the exploration rover to use one of its tools to study the soil near the rock.the next day, spirit began having problems.it answered radio signals, but it would not send back scientific information.��nasa officials began to work to correct the problem with spirit’s computer.the part of the computer that stores information was not working correctly.on february 1st, nasa announced that spirit’s computer memory had been successfully repaired.it will begin scientific examinations of rocks later this week.