Until the very latest moment of his existence, man has been Bound to the planet on which he originated and developed. Now he had the capability to leave that planet and move 【S1】______ out into the universe to those worlds which he has known previously only directly. Men have exploited parts of the moon, 【S2】______ put spaceships in orbit around another planet and possibly within the decade will land into another planet and explore it. Can we be 【S3】______ too bold as to suggest that we may be able to colonize other 【S4】______ planet within the no-too-distant future? Some have advocated 【S5】______ such a procedure as a solution to the population problem: ship the excess people off to the moon. But we must keep in head the 【S6】______ billions of dollars we might spend in carrying out the project. To maintain the earth't population at its present level, we could have to blast off into space 7,500 people every hour of every day of the year. Why are we spending so little money on space 【S7】______ exploration? Consider the great need for improving many aspects 【S8】______ of the global environment, one is surely justified in his concern for the money and resources that they are poured into 【S9】______ the space exploration efforts. But perhaps we should look at both side of the coin before arriving hasty conclusions. 【S10】______ 【S1】