介绍： A VISIT TO THE MOON

Last month I was lucky enough to have a chance to make a trip into space with my friend Li Yanping, an astronomer. We visited the moon in our spaceship!
Before we left, Li Yanping explained to me that the force of gravity would change three times on our journey and that the first change w...

介绍： A VISIT TO THE MOON

Last month I was lucky enough to have a chance to make a trip into space with my friend Li Yanping, an astronomer. We visited the moon in our spaceship!
Before we left, Li Yanping explained to me that the force of gravity would change three times on our journey and that the first change would be the most powerful. Then we were off. As the rocket rose into the air, we were pushed back into our seats because we were trying to escape the pull of the earth's gravity. It was so hard that we could not say anything to each other. Gradually the weight lessened and I was able to talk to him. "Why is the spaceship not falling back to the earth? On the earth if I fall from a tree I will fall to the ground." I asked. "We are too far from the earth now to feel its pull," he explained, "so we feel as if there is no gravity at all. When we get closer to the moon, we shall feel its gravity pulling us, but it will not be as strong a pull as the earth's." I cheered up i月球之旅

我的朋友李彦平是一位宇航员。上个月我有幸得到一个机会同他一起去太空旅行。我们乘宇宙飞船参观了月球。

在启程以前，李彦平向我解释说，在我们的航行中会有三次引力的改变，而第一次的改变将是最强的。随后我们就起航了。随着火箭徐徐升空，我们慢慢逃离地球的引力。但这种引力太强了，把我们重重地向后推在座位上，以至于我们彼此间都不能说话了。随后，这个力量慢慢减小，我才能够同他讲话。我问道：“为什么太空船不会向后朝地球的方向落下去呢？在地球上的时候，如果我从书上掉下来，总会朝地上落下去的。”李彦平解释说：“现在我们离地球太远了，感觉不到地球的拉力，所以我们好像一点儿也感觉不到地球引力了。当我们更接近月球时，就会感到月球的引力在拉我们。但是，月球的引力不像地球的引力那么大。”我立刻感到很高兴，由于失重我在太空舱里飘来飘去，我望着（身后的）地球越来越小，而（前方的）月球越来越大。

我们到达月球时，我就想立即进行探测。“来吧，”我说，“要是你讲得对，我的重量就会比地球小，而我就能够更自由地活动了。如果我在月球上呆的时间足够长的话，我甚至可能长得更高，我的体重肯定也会变得更轻！”我笑着从火箭的阶梯上爬下来。而当我试着向前迈步的时候，我发觉我被送出去很远，步子的跨度竟然是在地球上的两倍，因而我摔倒了。“天哪，”我大声说，“重力改变了，看来走路也的确需要练一练了。”过了一会儿，我才掌握了走路的诀窍，这才开始感到自如了。

摆脱月球引力不想摆脱地球引力那样痛苦。但是返回到地球的经历却是非常吓人的。我们惊奇地看着，随着丢引力的增加，宇宙飞船的外层燃烧起火。当我们回到地面时，我们又感到被重重地推到在座位上。我说道：“真是精疲力竭了，但也很激动人心。关于引力，我现在就懂得更多了。你认为下次我们可以上星球上去参观吗？”“当然可以，”他笑着说，“你想到那颗星球上去呢？”