登陆注册
14727000000095

第95章 LE VERRIER.(3)

Certain facts might be immediately presumed with reference to the unknown object. There could be no doubt that the unknown disturber of Uranus must be a large body with a mass far exceeding that of the earth. It was certain, however, that it must be so distant that it could only appear from our point of view as a very small object.

Uranus itself lay beyond the range, or almost beyond the range, of unassisted vision. It could be shown that the planet by which the disturbance was produced revolved in an orbit which must lie outside that of Uranus. It seemed thus certain that the planet could not be a body visible to the unaided eye. Indeed, had it been at all conspicuous its planetary character would doubtless have been detected ages ago. The unknown body must therefore be a planet which would have to be sought for by telescopic aid.

There is, of course, a profound physical difference between a planet and a star, for the star is a luminous sun, and the planet is merely a dark body, rendered visible by the sunlight which falls upon it.

Notwithstanding that a star is a sun thousands of times larger than the planet and millions of times more remote, yet it is a singular fact that telescopic planets possess an illusory resemblance to the stars among which their course happens to lie. So far as actual appearance goes, there is indeed only one criterion by which a planet of this kind can be discriminated from a star. If the planet be large enough the telescope will show that it possesses a disc, and has a visible and measurable circular outline. This feature a star does not exhibit. The stars are indeed so remote that no matter how large they may be intrinsically, they only exhibit radiant points of light, which the utmost powers of the telescope fail to magnify into objects with an appreciable diameter. The older and well-known planets, such as Jupiter and Mars, possess discs, which, though not visible to the unaided eye, were clearly enough discernible with the slightest telescopic power. But a very remote planet like Uranus, though it possessed a disc large enough to be quickly appreciated by the consummate observing skill of Herschel, was nevertheless so stellar in its appearance, that it had been observed no fewer than seventeen times by experienced astronomers prior to Herschel. In each case the planetary nature of the object had been overlooked, and it had been taken for granted that it was a star. It presented no difference which was sufficient to arrest attention.

As the unknown body by which Uranus was disturbed was certainly much more remote than Uranus, it seemed to be certain that though it might show a disc perceptible to very close inspection, yet that the disc must be so minute as not to be detected except with extreme care. In other words, it seemed probable that the body which was to be sought for could not readily be discriminated from a small star, to which class of object it bore a superficial resemblance, though, as a matter of fact, there was the profoundest difference between the two bodies.

There are on the heavens many hundreds of thousands of stars, and the problem of identifying the planet, if indeed it should lie among these stars, seemed a very complex matter. Of course it is the abundant presence of the stars which causes the difficulty. If the stars could have been got rid of, a sweep over the heavens would at once disclose all the planets which are bright enough to be visible with the telescopic power employed. It is the fortuitous resemblance of the planet to the stars which enables it to escape detection. To discriminate the planet among stars everywhere in the sky would be almost impossible. If, however, some method could be devised for localizing that precise region in which the planet's existence might be presumed, then the search could be undertaken with some prospect of success.

To a certain extent the problem of localizing the region on the sky in which the planet might be expected admitted of an immediate limitation. It is known that all the planets, or perhaps I ought rather to say, all the great planets, confine their movements to a certain zone around the heavens. This zone extends some way on either side of that line called the ecliptic in which the earth pursues its journey around the sun. It was therefore to be inferred that the new planet need not be sought for outside this zone. It is obvious that this consideration at once reduces the area to be scrutinized to a small fraction of the entire heavens. But even within the zone thus defined there are many thousands of stars. It would seem a hopeless task to detect the new planet unless some further limitation to its position could be assigned.

It was accordingly suggested to Le Verrier that he should endeavour to discover in what particular part of the strip of the celestial sphere which we have indicated the search for the unknown planet should be instituted. The materials available to the mathematician for the solution of this problem were to be derived solely from the discrepancies between the calculated places in which Uranus should be found, taking into account the known causes of disturbance, and the actual places in which observation had shown the planet to exist.

Here was indeed an unprecedented problem, and one of extraordinary difficulty. Le Verrier, however, faced it, and, to the astonishment of the world, succeeded in carrying it through to a brilliant solution. We cannot here attempt to enter into any account of the mathematical investigations that were necessary. All that we can do is to give a general indication of the method which had to be adopted.

同类推荐
热门推荐
  • 月食寻月

    月食寻月

    这个世界有一个地方,叫做小街。这条街没有人,有的只是鬼魅妖怪。小街原有123号,她的到来,让124号杂货铺生意火了起来。让本就神秘的小街变得更加神秘,一切只因她的身世,是一个未知的谜。洛花是古都皇族的公主,一千年前就死了,可是却莫名其妙的来到了这个地方。这个世界藏着许多秘密,她与他们一起,寻找这些秘密的源头。千年一次的暗月食将至,她要寻回明月,寻回古都。
  • 时间和青春,友情的沙漏

    时间和青春,友情的沙漏

    青春三年,无悔遇见,那是无处安放的青春,回不去的年少时光。岁月如流,再次相遇,你乱了阵脚,而我乱了心跳……车水马龙的都市里,期待着繁华落幕,只为寻找寂静。记忆残缺的只剩思恋,流年撕碎骄傲的容颜,以为时间可以冲淡那些美丽,心痛怎么越来越清晰,有些人的确从你心中走过,可最终是了无痕迹。凤落尘,你的名字是我白若璃的心事。
  • 中国台坛

    中国台坛

    本书介绍了上古基址、帝候高台、神话古台、释道神台、经诗文台、渔乐书台、长城诸台、历代将台、边防炮台、天文台、景观台、古戏台等中国著名台坛。
  • 集一切福德三昧经

    集一切福德三昧经

    本书为公版书,为不受著作权法限制的作家、艺术家及其它人士发布的作品,供广大读者阅读交流。
  • 二次元乱入

    二次元乱入

    我叫华子,好好的过我的生活,直到那天遇到了妲己,然后姜尚成而我二大爷,熊孩子哪吒成了我表弟......我才意识到自己的生活被乱入了,随即而来的是......--------------------都市生活搞笑文,没有升级打怪神马滴,只为在你为生活劳累的时候逗你一笑,足矣,希望大家多多捧场,收藏一下
  • 裂王传

    裂王传

    不一样的世界观不一样的遭遇。光之士的虐心成长历程。
  • 女王驾到,TFBOYS来接驾

    女王驾到,TFBOYS来接驾

    两个当红组合:TFBOYS,Smilinggirls一起回到重庆,经历种种危难的他们还能继续在爱情的道路上走下去吗?
  • 巧遇死神

    巧遇死神

    一名作者,被自己书中的主角,给带到了另一个以书为力量的世界,看他如何用自己的书,闯出一片天
  • 青梅竹马,安之若素

    青梅竹马,安之若素

    高中时的凌夏冉应一次意外,选择性失忆忘记了竹马李星辰,根据内心深处的指示出国留学。三年后,回国归来,再次与竹马相遇,夏冉应种种原因得出星辰则是自己忘记的那个人,俩人约定重新开始,成为朋友。在学院中,夏冉认识了许多的帅哥美女,也遇上了一个喜欢他的“高冷王子”安羽枫,身边发生了许多不可思议的事情。她会恢复记忆吗?她会和星辰在一起呢还是和羽枫在一起呢?还是……?
  • 征服游戏:早安,小娇妻

    征服游戏:早安,小娇妻

    他桎梏她,强逼她交出她给他生的孩子。“没有没有没有!”“没有?那现在就再生一个!”无数个日夜地狱般的索爱,她被他摆布得无路可逃。待孩子生下来后,她正欲逃之夭夭,却依旧被他压在墙上。“宝贝,谁说只生一个的?”【他宠她,宠到每一次心跳都是为了她,全世界,只有她这个傻瓜不知道……】