克卜勒(1571～1630年)

Kepler, Johannes

德国天文学家。出身贫穷，他获得奖学金到图林根大学就读。1594年获得硕士学位，此後在奥地利担任数学教师。他发展出一种神秘理论，认为宇宙由五种规律的多面体包成球形而造成，每对多面体之间有一个行星。他把这个主题的报告寄送给第谷，他乃邀请克卜勒加入自己的研究小组。为了理解大气中光的折射，他成为正确解释眼睛如何见物、眼镜如何改善视力、望远镜中光线如何作用的第一人。1609年发表了他的发现：火星轨道为椭圆形，而非正圆形，因此他假设所有天体的轨道都是这样。这个事实成为克卜勒第一个行星运动定律的基础。他也确定，行星在靠近太阳时会移动较快，1619年他表示由一个简单的数学公式可以得出行星距日远近的轨道周期。1620年因母亲被控行巫而辩护，其实也是为了维护自己的名誉。

English version：

1571～1630年

Kepler, Johannes

German astronomer. Born into a poor family, he received a scholarship to the University of Tübingen. He received an MA in 1594, after which he became a mathematics teacher in Austria. He developed a mystical theory that the cosmos was constructed of the five regular polyhedrons, enclosed in a sphere, with a planet between each pair. He sent his paper on the subject to Tycho Brahe, who invited Kepler to join his research staff. In attempting to understand atmospheric refraction of light, he became the first to explain accurately how the eye sees, how eyeglasses improve vision, and what happens to light in a telescope. In 1609 he published his finding that the orbit of Mars was an ellipse and not the perfect circle hitherto presumed to be the orbit of all celestial bodies. This fact became the basis of the first of Kepler's laws of planetary motion. He also determined that planets move faster as they near the sun, and in 1619 he showed that a simple mathematical formula related the planets' orbital periods to their distance from the sun. In 1620 he defended his mother from charges of witchcraft, thereby preserving his own reputation as well.