About 350 years ago Galileo made a telescope and looked through it at the sun. What he saw both surprised and frightened him, for he saw dark spots on the sun which at once suggested to him that God had not made the world quite as perfect as he had previously believed. He hesitated to make his discovery known. Meanwhile other scientists noticed the same lack of solar perfection and proclaimed (宣布) the fact.
大约在350年前，伽利略发明了望远镜，并利用它观察太阳。令他震惊和恐惧的是，他在太阳表面看到了太阳黑斑。这个结果立刻让他联想到上帝创造的世界并非他以前相信的那样完美。他犹豫是否把他的发现公之于众。与此同时，其他的科学家也注意到了太阳的这个缺陷，并且公布了这个事实。
But Galileo continued his observations and was soon rewarded with another discovery. Fixing his attention on a single sunspot (太阳黑子) group, he noticed that in a few days it had moved in position, just as if the sun itself were turning. Afterwards he found a sunspot group which lived long enough to disappear from view on the western limb (边缘) of the sun, to re-appear on its eastern limb, and finally to regain its old position. This led him to conclude that the sun itself was rotating and that the time it took to make one complete turn was about twenty-five to twenty-seven days. Actually we know from the drawings which Galileo made of sunspots that there must have been quite a lot of them at the time of his observations in the years 1611 and 1612. If he had gone on making his drawings in the years that immediately followed, we know that he would almost certainly have noticed that sunspots were becoming fewer and smaller. But he became interested in other things and so he failed to recognize that there is a kind of long-term cycle in sunspot activity, the sunspots increasing and decreasing as the years go on. Later this discovery of the sunspot activity was made by one of the most patient observers in the history of science, a German chemist, Charles Schwabe.
但是伽利略继续他的观测，不久又获得了新的发现。他把注意力固定到一个单个太阳黑子群上，他注意到一些天之后黑子回到原来的位置，就好像太阳自身在转。之后他发现一个黑子群，其从太阳西边消失，从太阳东边再现，最终回到原来的位置。这个引导他得出太阳自身在转这个结论，旋转一个完整周期大约需要25到27天。实际上我们从伽利略在1611年和1612年画的太阳黑子观测图可以得知当时出现大量的太阳黑子。如果他在接下来的数年中继续画图，那么我们知道他将一定会发现太阳黑子变得越来越少和越来越小。但是他开始对别的事情感兴趣，所以他没能认识到太阳黑子活动有一种长期循环性，太阳黑子会随着时间增加和减少。后来这个太阳黑子活动的发现被科学史上最耐心的人之一，德国化学家Charles Schwabe所发现。