问题详情

Space is filled with radiant energy and beyond earth"s atmosphere this energy flow steadily and intensely from the sun. An abundant and essential【C1】______of energy would be used in space by developing satellite solar【C2】______stations. To live in space, humans must be protected【C3】______the fierce intensity and penetrating sunlight. The colony will have to have enough energy to【C4】______a fairly uniform. temperature. The sun is not dimmed【C5】______an atmosphere. Shaded materials not【C6】______to direct sunlight will almost be absolute zero, while the temperature can soar above the【C7】______point. The colony will need to have both heaters and【C8】______Fortunately, sun"s energy can be converted【C9】______electricity. Converting sun"s energy, we would【C10】______stations in the space that would intercept【C11】______sunlight. The stations intercept enough sunlight to【C12】______five nuclear reactors and they could be as【C13】______as nine miles long and four miles wide while they weigh twenty thousand tons. This is a【C14】______free way to generate electricity and cost no【C15】______than coal or nuclear energy. Solar cells do the actual converting. A useful material found in lunar soil is silicon which is used to make solar cells.【C16】______we can produce a large amount of these cells and then we avoid any problems of【C17】______the material from earth. A solar cell is made from two thin layers of silicon. Sunlight【C18】______on the cell shakes the electrons【C19】______, and then these electrons move off into an outside circuit, which is detected as an electrical current. Things are arranged【C20】______most of the work involved in generating the electricity is done by forces associated with the atoms themselves.
【C1】
A．treasure
B．property
C．resource
D．source