Kepler's World

 

开普勒的世界

Much has been made of the 400th anniversary this year of Galileo pointing a telescope at the moon and jotting down what he saw.

400年前伽利略用望远镜观测月球并简要记录了观测结果，400年后的今天我们很隆重地纪念了这一历史性事件。

But 2009 is also the 400th anniversary of the publication by Johannes Kepler,a German mathematician and astronomer,of "Astronomia Nova".

不过，2009年也是德国数学家和天文学家约翰尼斯?开普勒发表《新天文学》400周年。

This was a book that contained an account of his discovery of how the planets move around the sun,correcting Copernicus's own more famous but incorrectly formulated description of the solar system.

这部著作论述了他发现的行星围绕太阳运行的规律，从而修正了哥白尼给太阳系作的错误描述，尽管哥白尼的论述更加广为人知。

And it established the laws for planetary motion on which Isaac Newton based his work.

另外，该著作还创立了行星运行定律，为艾萨克?牛顿的发现奠定了基础。

Four centuries ago the received wisdom was that of Aristotle,who asserted that the Earth was the centre of the universe,

四个世纪以前，人们普遍接受的是亚里斯多德的观点。他认为地球是宇宙的中心，

and that it was encircled by the spheres of the moon,the sun, the planets and the stars beyond them.

月球、太阳以及其他所有的行星和恒星都绕着地球旋转。

Copernicus had noticed inconsistencies in this theory and had placed the sun at the centre,with the Earth and the other planets travelling around the sun.

但是，哥白尼注意到这个理论的一些观点自相矛盾，他认为太阳才是宇宙的中心，地球和其他星球都绕着太阳运行。

Some six decades later when Kepler tackled the motion of Mars,he proposed a number of geometric models,checking his results against the position of the planet as recorded by his boss.

大约60年后，开普勒为研究火星运行轨迹假设了大量的几何模型，但是根据这些模型预测出的结果和他上司记录的火星位置不一致。

Kepler repeatedly found that his model failed to predict the correct position of the planet.

当开普勒反复发现他的模型无法正确预测火星的位置时，他决定对它进行改造。

He altered it and, in so doing,created first egg-shaped "orbits" and,finally, an ellipse with the sun placed at one focus.

开普勒先是建立了一个蛋型“轨道”，并在此基础上提出了椭圆轨道的模型，在这个模型中，太阳位于椭圆轨道的其中一个焦点上。

Kepler went on to show that an elliptical orbit is sufficient to explain the movement of the other planets and to devise the laws of planetary motion that Newton built on.

接着，开普勒又证明椭圆轨道模型同样适用于解释其他行星的运行轨迹，并且依此模型足以归纳出行星运行定律，而这些定律日后成为了牛顿的理论基础。

A.E.L. Davis this week told astronomers and historians that it was the rotation of the sun that provided Kepler with what he thought was one of the causes of the planetary motion that his laws described,although his reasoning would today be considered entirely wrong.

A．E.L. Davis在这周告诉天文学家和历史学家说，正是太阳自转现象让开普勒得到启发，从而得出他在行星运行定律中所描述的引起行星运动的其中一个原因，尽管他的论证过程在现在看来是完全错误的。

In 1609 astronomy and astrology were seen as intimately related;mathematics and natural philosophy,meanwhile, were quite separate areas of endeavor;however, Kepler sought physical mechanisms to explain his mathematical result.

1609年，天文学和星象学被视为联系紧密的两个学科．而数学和物理学则是完全独立的两个研究领域．但开着勒却试图以物理机制来验证数学结墨。

He wanted to know how it could be that the planets orbited the sun.

他想弄清楚行星怎么会沿一定的轨迹绕太阳运行。

Once he learned that the sun rotated,he comforted himself with the thought that the sun's rays must somehow sweep the planets around it while some magnetism accounted for the exact elliptical path.

当他得知太阳存在自转现象时，他就自欺欺人地认为太阳的光线无论如何一定会照射到周围的行星，而某种磁力使堡这些行星沿着规则的椭圆轨道运行。

As today's astronomers struggle to determine whether they can learn from the past,Kepler's tale provides a salutary reminder that only some explanations stand the test of time.

现在的天文学家们极力想知道他们是否能从历史中得到一些启示，而开普勒的故事的积极意义在于：它提醒我们并不是所有理论都经得起时间的考验。