The immediate result of Barbicane's proposition was to place upon the orders of the day all the astronomical facts relative to the Queen of the Night. Everybody set to work to study assiduously.One would have thought that the moon had just appeared for the first time, and that no one had ever before caught a glimpse of her in the heavens.The papers revived all the old anecdotes in which the“sun of the wolves”played a part；they recalled the influences which the ignorance of past ages ascribed to her；in short, all America was seized with selenomania, or had become moon-mad.

The scientific journals, for their part, dealt more especially with the questions which touched upon the enterprise of the Gun Club. The letter of the Observatory of Cambridge was published by them, and commented upon with unreserved approval.

Until that time most people had been ignorant of the mode in which the distance which separates the moon from the earth is calculated. They took advantage of this fact to explain to them that this distance was obtained by measuring the parallax of the moon.The term parallax proving“caviare to the general”，they further explained that it meant the angle formed by the inclination of two straight lines drawn from either extremity of the earth's radius to the moon.On doubts being expressed as to the correctness of this method, they immediately proved that not only was the mean distance 234，347 miles, but that astronomers could not possibly be in error in their estimate by more than seventy miles either way.

To those who were not familiar with the motions of the moon, they demonstrated that she possesses two distinct motions, the first being that of rotation upon her axis, the second being that of revolution round the earth, accomplishing both together in an equal period of time, that is to say, in twenty-seven and one-third days.

The motion of rotation is that which produces day and night on the surface of the moon；save that there is only one day and one night in the lunar month, each lasting three hundred and fifty-four and one-third hours. But, happily for her, the face turned toward the terrestrial globe is illuminated by it with an intensity equal to that of fourteen moons.As to the other face, always invisible to us, it has of necessity three hundred and fifty-four hours of absolute night, tempered only by that“pale glimmer which falls upon it from the stars”.

Some well-intentioned, but rather obstinate persons, could not at first comprehend how, if the moon displays invariably the same face to the earth during her revolution, she can describe one turn round herself. To such they answered，“Go into your dining-room, and walk round the table in such a way as to always keep your face turned toward the center；by the time you will have achieved one complete round you will have completed one turn around yourself, since your eye will have traversed successively every point of the room.Well, then, the room is the heavens, the table is the earth, and the moon is yourself.”And they would go away delighted.

So, then the moon displays invariably the same face to the earth；nevertheless, to be quite exact, it is necessary to add that, in consequence of certain fluctuations of north and south, and of west and east, termed her libration, she permits rather more than half, that is to say, fifty-seven percent, to be seen.

As soon as the ignoramuses came to understand as much as the director of the observatory himself knew, they began to worry themselves regarding her revolution round the earth, whereupon twenty scientific reviews immediately came to the rescue. They pointed out to them that the firmament, with its infinitude of stars, may be considered as one vast dial-plate, upon which the moon travels, indicating the true time to all the inhabitants of the earth；that it is during this movement that the Queen of Night exhibits her different phases；that the moon is full when she is in opposition with the sun, that is when the three bodies are on the same straight line, the earth occupying the center；that she is new when she is in conjunction with the sun, that is, when she is between it and the earth；and, lastly that she is in her first or last quarter, when she makes with the sun and the earth a right angle of which she herself occupies the apex.

Regarding the altitude which the moon attains above the horizon, the letter of the Cambridge Observatory had said all that was to be said in this respect. Every one knew that this altitude varies according to the latitude of the observer.But the only zones of the globe in which the moon passes the zenith, that is, the point directly over the head of the spectator, are of necessity comprised between the twenty-eighth parallels and the equator.Hence the importance of the advice to try the experiment upon some point of that part of the globe, in order that the projectile might be discharged perpendicularly, and so the soonest escape the action of gravitation.This was an essential condition to the success of the enterprise, and continued actively to engage the public attention.

Regarding the path described by the moon in her revolution round the earth, the Cambridge Observatory had demonstrated that this path is a re-entering curve, not a perfect circle, but an ellipse, of which the earth occupies one of the foci. It was also well understood that it is farthest removed from the earth during its apogee, and approaches most nearly to it at its perigee.

Such was then the extent of knowledge possessed by every American on the subject, and of which no one could decently profess ignorance. Still, while these principles were being rapidly disseminated many errors and illusory fears proved less easy to eradicate.

For instance, some worthy persons maintained that the moon was an ancient comet which, in describing its elongated orbit round the sun, happened to pass near the earth, and became confined within her circle of attraction. These drawing-room astronomers professed to explain the charred aspect of the moon—a disaster which they attributed to the intensity of the solar heat；only, on being reminded that comets have an atmosphere, and that the moon has little or none, they were fairly at a loss for a reply.

Others again, belonging to the doubting class, expressed certain fears as to the position of the moon. They had heard it said that, according to observations made in the time of the Caliphs, her revolution had become accelerated in a certain degree.Hence they concluded, logically enough, that an acceleration of motion ought to be accompanied by a corresponding diminution in the distance separating the two bodies；and that, supposing the double effect to be continued to infinity, the moon would end by one day falling into the earth.However, they became reassured as to the fate of future generations on being apprised that, according to the calculations of Laplace, this acceleration of motion is confined within very restricted limits, and that a proportional diminution of speed will be certain to succeed it.So, then, the stability of the solar system would not be deranged in ages to come.

There remains but the third class, the superstitious. These worthies were not content merely to rest in ignorance；they must know all about things which had no existence whatever, and as to the moon, they had long known all about her.One set regarded her disc as a polished mirror, by means of which people could see each other from different points of the earth and interchange their thoughts.Another set pretended that out of one thousand new moons that had been observed, nine hundred and fifty had been attended with remarkable disturbances, such as cataclysms, revolutions, earthquakes, the deluge, etc.Then they believed in some mysterious influence exercised by her over human destinies—that every Selenite was attached to some inhabitant of the earth by a tie of sympathy；they maintained that the entire vital system is subject to her control, etc.But in time the majority renounced these vulgar errors, and espoused the true side of the question.As for the Yankees, they had no other ambition than to take possession of this new continent of the sky, and to plant upon the summit of its highest elevation the star-spangled banner of the United States of America.

巴比凯恩的提议使得所有有关月球的天文现象都成为人们的谈资。人人都在潜心研究月球。好像月球是首次出现在地平线上，谁都未曾在天空中见过它似的。各种报纸连篇累牍地再次掀起“狼的太阳”那古老传说的热潮。人们回味着原始时代由于愚昧而赋予月亮这个称呼所产生的影响。简而言之，全美国人都变成了月球迷。

而那些科学杂志则更加专业地探讨了大炮俱乐部所提出的问题。剑桥天文台的那封回信被公布出来，人们做了高度评价，毫无保留地表示了赞同。

在此之前，大多数人都弄不明白人们是如何计算出月球和地球之间的距离的。天文学家们趁此机会告诉他们，这个距离是通过测量月球的视差求得的。如果“视差”一词人们听不懂的话，天文学家们就进一步解释说，那是从地球半径的两端到月球的两条直线构成的角。要是他们怀疑这种方法的精确性的话，就会有人立即向他们证明，不但这个平均距离是二十三万四千三百四十七英里，而且天文学家们计算的误差不会超过七十英里。

对于那些不太了解月球运行规律的人，报纸每天都刊登文章为他们介绍，月球有着两种不同的运动：一种是绕着轴心的自转，另一种是围绕地球的公转。这两种运动都在一个相同的时间段——二十七又三分之一天——里完成。

自转运动也就是在月球表面产生白昼与黑夜的运动。而每个朔望月只有一个白昼和一个黑夜，而且二者的持续时间都是三百五十四又三分之一小时。不过，对于月球来说，幸运的是，它面对地球的那一面被地球那相当于十四个月亮光照强度的光线照亮。至于它那背朝地球的一面，始终没人看见，当然是三百五十四小时都处于绝对的黑夜之中，只是依靠“从其他的星星上散落下来的光亮保持温度而已”。

有一些一根筋的、脑子有点儿冥顽不灵的人，一开始并不明白月球在公转时始终不变地面朝着地球，而实际上它也在自转着。对于这些人，人们便告诉他们：“如果您去餐厅，而且眼睛始终盯着餐桌的中心绕着餐桌转，当您转完了一圈之后，您其实已经自己绕着自己转了一圈，因为您的目光相继扫视了一遍餐桌的各个点。喏，我们不妨把餐厅视作天空，餐桌就是地球，而月球就是您自身！”经这么一比喻，他们就明白了，于是就高高兴兴地离开了。

因此，月球总是只有一个面对着地球。但是，为了准确起见，必须补充一点：由于月球由北向南、由西向东的某种“摆动”的缘故，人们可以看到的月面比它的实际月面的一半还要大一点儿，也就是能看到百分之五十七的月面。

当那些无知的人对月球的自转了解得与剑桥天文台台长一样多的时候，他们就开始非常担心月球绕着地球公转的情况，因此，二十家科学杂志便立即向他们介绍这是怎么一回事。它们向人们指出：挂着满天星斗的天穹可以被视作一个巨大的钟面，月球便在上面运行着，向地球上的居民们指示着准确的时间；月球正是在运行过程中呈现各种月相的。当它背向太阳时，也就是说，当三个星体连成一线，而地球夹在中间的时候，月球呈满月状；当月球与太阳合在一起时，也就是说当它位于地球和太阳之间时，月球呈新月状；最后，当月球与太阳和地球构成一个直角而它又居于直角顶端时，呈现的就是上弦月或下弦月。

至于月球所能达到的天际高度问题，剑桥天文台的回信中已经详细回答了。人人皆知，这一天际高度是随着观测点纬度的变化而变化的。但是，月球通过天顶最高点，也就是说，它直接位于观测者头顶上方的唯一的地区，必须是在南北纬的28°和地球赤道之间。因此，回信中强调指出，试验必须是在地球这一地区的任意一个点进行，这样炮弹才能垂直发射，从而尽快地摆脱地心引力。这是保证试验成功的一个重要条件，而公众对此也极其关注。

至于月球围绕地球公转的轨迹问题，剑桥天文台已经解释得十分清楚：这个轨迹是一条凹曲线，不是圆形而是椭圆形，地球位于某一个圆心上。所有的行星或卫星，它们的轨迹都是这种形状，而且理论力学也证实了它们的轨迹不会出现其他形状。当然，月球在远地点时距离地球最远，而在近地点时距离地球最近。

任何一个美国人不管愿意与否，都得了解这一点，任何人都不可以不懂得。然而，虽然说这些科学原理很快地普及开来，但也必然会出现很多的谬误，会出现一些毫无道理的担忧，而且很难消弭。

例如，有一些正直的人坚称，月球曾是一颗古老的彗星，它在沿着扁长的轨道绕着太阳转，恰好经过地球附近时，被地球的引力圈吸引住。这些坐而论道的天文学家声称，这样就可以解释月球表面的焦黑状况了，认为这是光亮的月球无法弥补的不幸。只不过，当人们向他们指出彗星上有空气，而月球上则空气稀薄或者根本没有空气时，他们便瞠目结舌，无言以对了。

另有一些好像很胆怯的人，他们对月球感到有些害怕。他们听说自从哈里发[24]时代所进行的观测以来，月球的公转在按照一定的比例加速。他们由此而进行了推断，倒也十分符合逻辑：运行速度的加快必然导致两个星球之间的距离缩小；而且，如果这种双重作用没完没了地继续下去的话，月球总有一天会掉落到地球上。不过，当人们告诉他们，根据法国的一位名叫拉普拉斯的著名数学家的计算，这种运行的加速只局限在极其有限的范围之内，而且会出现一定比例的减速，因此，太阳系的平衡在未来的几个世纪中是不会被打破的。这么一来，他们也就放下心来，不再为子孙后代担忧了。

最后，只剩下那些愚昧而迷信的人了。这些人倒也不是完全无知，他们对并不存在的事物倒甚为了解；对于月亮，他们知道得就更多了。他们中的一些人把月亮视作一面光滑的镜子，通过它，人们可以看见地球的各个不同的地方，并相互交流沟通。另有一些人则声称，在观察过的一千次新月中，有九百五十次导致了重大的变故，诸如大灾大难、革命、地震、洪水等。他们因此而认为，这个黑夜星球对人类的命运有着神秘的影响；他们觉得每一个月球人都与某个地球人有感应；他们坚持认为，生命体系完全受它的支配；等等。但是随着时间的推移，这些无稽之谈终究要被抛弃，唯一的真理必须回归。至于美国佬们，他们不再存有其他的野心，只是想要独霸这块天空中的新大陆，在月球的最高峰上插上美利坚合众国的星条旗。