Part 7

’Tis certain moreover, that the Moon has no Air or Atmoſphere ſurrounding it as we have. For then we could never ſee the very outermoſt Rim of the Moon ſo exactly as we do, when any Star goes under it, but its Light would terminate in a gradual faint Shade, and there would be a ſort of a Down as it were about it; not to mention that the Vapours of our Atmoſphere conſiſt of Water, and conſequently that where there are no Seas or Rivers, there can be no Atmoſphere. This is that notable difference between the Moon and us that hinders all probable Conjectures about it. If we could but once be ſure that there were Seas and Rivers in it, it would be no weak Argument to prove that it has alſo all other Furniture which belongs to our Earth, and the Opinion of Xenophanes might be true, that it has its Inhabitants, Cities, and Mountains. But as ’tis, I cannot imagine how any Plants or Animals, whole whole nouriſhment comes from liquid Bodies, can thrive in a dry, waterleſs, parch’d Soil.

[The Conjecture of its Plants and Animals very dubious.]

What then, is it credible that this great Ball was made for nothing but to give us a little Light in the Night-time, or to raiſe our Tides in the Sea? May there not be ſome People there that may have the Pleaſure of ſeeing our Earth turn upon itſelf, preſenting them ſometimes with a Proſpect of Europe and Africa, and then of Aſia and America; ſometimes half of it bright, and ſometimes full? And muſt all thoſe Moons round Jupiter and Saturn be condemned to the ſame Uſeleſneſs? I do not know what to ſay concerning it, becauſe I know of nothing like them to found a Conjecture upon. And yet ’tis not improbable that thoſe great and noble Bodies have ſomewhat or other growing and living upon them, though very different from what we ſee and enjoy here. Perhaps their Plants and Animals may have another ſort of Nouriſhment there. Perhaps the Moiſture of the Earth there is but juſt ſufficient to cauſe a Miſt or Dew, which may be very ſuitable to the Growth of their Herbs. This I remember is Plutarch’s Opinion, in his Dialogue upon this Subject. For in our Earth a very little Water drawn from the Sea into Dew, and falling down again upon the Herbs, would be ſufficient for all our Needs, without any Rain or Showers. But theſe are mere Gueſſes, or rather Doubts, but yet they are the [Jupiter’s and Saturn’s Moons turn always the ſame Side to them.] beſt we can make of this, and all thoſe other Moons: for, as I ſaid before, they are all of the ſame nature, which is proved likewiſe by this, that as our Moon can afford us the Sight never but of one Side of her, ſo they turn always the ſame Face to their primary Planets. It may perhaps ſeem ſtrange, how we ſhould come to know this; but ’tis no hard matter, after that Obſervation which I juſt now made, that the outermoſt of Saturn’s Moons can never be ſeen but when ſhe is on the Weſt-ſide of her Planet. The reaſon of which is plainly this, that one Side of her is darker, and does not reflect the Light ſo much as the other, which when it is turned towards us, we cannot ſee by reaſon of its weak Light. This always happening when ’tis Eaſt of him, and never on the other Side, is a manifeſt proof that ſhe always keeps the ſame Side toward Saturn. Now ſince the outermoſt of Saturn’s and our Moon carry themſelves thus to the Planets round which they move, who can well doubt it of all the reſt round Jupiter and Saturn? And there’s a very good reaſon for it, namely, that the matter of which thoſe Moons conſiſt, being heavier, and more ſolid on the Side that is averſe from us, than on that which we have the Sight of, does conſequently fly with a greater force from the Centre of its Orbit: for otherwiſe, according to the Laws of Motion, it ſhould turn the ſame Side always, not to its Planets, but to the ſame fix’d Stars.

This Poſition of the Moons, in reſpect of their Planets, muſt occaſion a great many very ſurprizing Appearances to their Inhabitants, if they have any, which is very doubtful, but may for the preſent be ſuppos’d. An enquiry into our Moon may ſerve for all the reſt. Its Globe is divided into two Parts, in ſuch a manner, that thoſe who live on one Side never loſe the ſight of us, and thoſe on the other never enjoy it. Except only ſome few who live on the Confines of each of theſe, who loſe us, and ſee us again by turns. The Earth to them muſt ſeem [The Aſtronomy of the Inhabitants of the Moon.] much larger than the Moon doth to us, as being in Diameter above four times bigger. But that which is moſt ſurprizing, is, that Night and Day they ſee it always in the very ſame part of the Heaven, as if it never moved: ſome of them as if ’twas falling upon their Heads: others ſomewhat above the Horizon, and others always in the Horizon, ſtill turning upon it ſelf, and preſenting them every twenty ſour Hours with a View of all its Countries, even of thoſe that lie near the Poles (I could wiſh my ſelf in the Moon only for the ſight of them) yet unknown and undiſcovered by us. They have it in its monthly Wane and Increaſe, they ſee it half, and horned, and full, by turns, juſt as we do the Body of the Moon. But the Light that they receive of us is five times larger than what we receive from them. So that in dark Nights that part that hath the Advantage of being towards us, receives a very glorious Light from us, tho’ Kepler thought otherwise. Their Days are always of the ſame Length with their Nights; and the Sun riſing and ſetting to them but once in one of our Months, makes the time both of their Light and Darkneſs to be equal to 15 of our Days. If their Bodies were of the ſame Materials with ours, thoſe that have the Sun pretty high in their Horizon, would be almoſt roaſted in ſuch long Days. For the Sun is not farther from them than he is from us. This will be the Caſe of thoſe that live upon the Borders of the two Hemiſpheres we mentioned; but thoſe that live under the Poles of the Moon will be juſt about as hot as our Whale-fiſhers about Iſland and Nova Zemla are, in the Summer-time: who are in ſo little danger of being roaſted, that in the middle of their Summer, in their Days of three Months length, they very often find it extreme Cold. I call thoſe the Poles of the Moon, round which the fix’d Stars ſeem to turn to its Inhabitants, which are different from ours, and alſo from thoſe of the Ecliptick, although they move round theſe latter, at the diſtance of five Degrees, in a period of nineteen Years. Their Year they count by the Motion of the Stars, and their return to the Sun, and ’tis the ſame with ours. They can eaſily do it, becauſe they have the Stars Day and Night, notwithſtanding the Light of the Sun: for they have no Atmoſphere (which is the only reaſon that we don’t every Day enjoy the ſame Sight) to hinder their Obſervations. Nor have they any Clouds to obſtruct their View, ſo that it is eaſier for them to find out the Courſes of the Planets, but more difficult to make a true Syſtem of them. For they will be apt to lay a wrong Foundation, by ſuppoſing that their Earth ſtands ſtill, which will lead them into more dangerous Errors than [This may be applied to the Moons about Jupiter and Saturn.] ever it did us. All that I have ſaid belongs as well to Jupiter’s and Saturn’s Satellites as to our Moon, in reſpect of the Planets they move round. The Length of their Day and Night is always equal to the Time of their Revolution: For example, the fifth Moon moves round Saturn in 80 Days, and the Days and Nights there are equal to Forty of ours. Both their Summer and Winter (Saturn moving round the Sun in thirty Years) are fifteen Years long. Therefore it is impoſſible but that their way of living muſt be very different from ours, having ſuch tedious Winters, and ſuch long watching and ſleeping times.

Having thus explained the primary and ſecondary Planets round the Sun, we ſhould next ſet about the third Sort, the Sun and fix’d Stars; but before we do that, it would be worth while to ſet before you at once, in a clearer and more plain Method than hitherto, the Magnificence and Fabrick of the Solar Syſtem. Which we can’t poſſibly do in ſo ſmall a Space as one of our Leaves will but admit of, becauſe the Bodies of the Planets are ſo prodigiouſly ſmall in companion of their Orbs. But what is wanting in Figure ſhall be made up in Words. Going back then to the firſt Scheme, ſuppoſe another [Fig. 1.] like it, and proportionable, drawn upon a very large ſmooth Plain; whoſe outermoſt Circle repreſenting the Orb of Saturn, muſt be conceived three hundred and ſixty Foot in Semidiameter. In which you muſt place the Globe and Ring of Saturn of that [Fig. 2.] Bigneſs as the 2d Figure ſhows you. Let all the other Planets be ſuppoſed every one in his own Orbit, and in the middle of all the Sun, of the ſame Bigneſs that That Figure repreſents, namely, about four Inches in Diameter. And then the Orbit or Circle in which the Earth moves, which the Aſtronomers call the Magnus Orbis, muſt have about ſix and thirty Foot in Semidiameter. In which the Earth muſt be conceived moving, not bigger than a grain of Millet, and her Companion the Moon ſcarcely perceivable, moving round her in a Circle a little more than two Inches Diameter, as in [Fig. 5.] the Figure here adjoined, where the Line A B repreſents a ſmall portion of that Circle which the Earth moves in: the ſmall Circle therein C is the Earth, and the Circle D E the Path of the Moon round it, in which the Body of the Moon is D.

The outermoſt of Saturn’s Moons moves in an Orbit whoſe Semidiameter is 29 Inches; that of Jupiter in a ſomewhat ſmaller, whoſe Semidiameter is 19 and a quarter.

And thus we have a true and exact Deſcription of the Sun’s Palace, where the Earth will be Twelve thouſand of its Semidiameters diſtant from him, which in German Miles makes above ſeventeen Millions. But perhaps we may have a clearer Comprehenſion of this vaſt Length, by comparing it with ſome very ſwift Motion after the Example of Heſiod the Poet, who imagin’d that an Anvil let fall from the Top of Heaven, reach’d the Earth the tenth Day of its Journey, and in ten more arriv’d at the Bottom of Hell, the end of it: ſo making the Earth the mid-way between Heaven and Hell. I ſhan’t make uſe of the Anvil, but of ſomething as good, namely, a Bullet ſhot out of a great Gun, which may travel perhaps in a Moment, or Pulſe of an Artery, about a hundred Fathom, as is proved by thoſe Experiments that Merſennus in a Treatiſe of his relates; by which the Sound was found to extend itſelf eighty hundredth parts in the [The immenſe diſtance between the Sun and Planets illuſtrated.] ſame time. I ſay then, that ſuppoſing a Bullet to move with this Swiftneſs from the Earth to the Sun, it would ſpend 25 Years in its Paſſage. To make a Journey from Jupiter to the Sun, would require 125, and from Saturn thither 250 Years. This account depends upon the meaſure of the Earth’s Diameter, which, according to the accurate Obſervations of the French, is 6538594 times ſix Paris Feet, one Degree being 57060 of that Meaſure. This ſhows us how vaſt thoſe Orbs muſt be, and how inconſiderable this Earth, the Theatre upon which all our mighty Deſigns, all our Navigations, and all our Wars are tranſacted, is when compared to them. A very fit Conſideration, and Matter of Reflection, for thoſe Kings and Princes who ſacrifice the Lives of ſo many People, only to flatter their Ambition in being Maſters of ſome pitiful Corner of this ſmall Spot. But to return to the matter in hand, now we have given you an account of the Sun’s proportion to thoſe Orbs and Bodies, we’ll ſee what more we can ſay of him.

[No ground for Conjecture in the Sun.]

And ſome have thought it not improbable but that the Sun himſelf has alſo his Inhabitants. But upon what reaſon I cannot imagine, there being leſs ground for a Probability in him than in the Moon. For we are not yet ſure, whether he be a ſolid or liquid Globe; altho’, if my Notion of Light be true, upon that account I ſhould rather think him liquid: which his Roundneſs and equal diſtribution of his Light to all parts are an Argument for. For that very ſmall inequality on his Surface, which is diſcovered by the Teleſcopes, (and that not always neither) which makes Men fancy they ſee boiling Seas and belching Mountains of Fire, is nothing but the trembling Motion of the Vapours our Atmoſphere is full of near the Earth; which is likewiſe [The Faculæ in the Sun not eaſily ſeen.] the Cauſe of the Stars twinkling. Nor could I ever have the Luck to diſcern thoſe bright Spots in the Sun which they boaſt as much of as they do of his dark ones, which latter I have very often ſeen; ſo that I have very good Reaſon to doubt whether there be any thing in the Sun brighter than the Sun itſelf. For by the moſt exact Obſervations, I could never find any ſuch pretended to be ſeen any where but juſt about his dark Spots; and it is no great wonder that thoſe Parts which are ſo near the darker, ſhould appear ſomewhat [By reaſon of its Heat no Inhabitants like ours can live in the Sun.] brighter than the reſt. That the Sun is extremely hot and fiery, is beyond all diſpute, and ſuch Bodies as ours could not live one Moment in ſuch a Furnace. We muſt ſuppoſe a new ſort of Animals then, ſuch as we have no Idea or Likeneſs of among us, ſuch as we can neither imagine nor conceive: which is as much as to ſay, that we can make no Suppoſition at all about them. No doubt that glorious and vaſt Body was made for ſome noble End and Uſe, and fram’d with excellent Deſign. And I think we all very well know and feel its Uſefulneſs in that effuſion of Light and Heat to all the Planets round it; in the Preſervation and Happineſs of all living Creatures, and that not only in our Ball, but in thoſe vaſt Globes of Jupiter and Saturn, not contemptible when compared with its own. Theſe are ſuch great, ſuch wiſe Ends, that it is not ſtrange that the Sun ſhould have been made, if it had been only upon their account. For, as for Kepler’s Fancy, that he hath another Office, namely, to help on the Motion of the Planets in their own Orbs, by turning about his own Axis (which he would fain eſtabliſh in his Epitome of the Copernican Syſtem) I ſhall give good Reaſons why I cannot aſſent to it.

[The ſix’d Stars so many Suns.]

Before the Invention of Teleſcopes, it ſeemed to contradict Copernicus’s Opinion, to make the Sun one of the fix’d Stars. For the Stars of the firſt Magnitude being eſteem’d to be about three Minutes Diameter; and Copernicus (obſerving that tho’ the Earth changed its Place, they always kept the ſame diſtance from us) having ventur’d to ſay that the Magnus Orbis was but a Point in reſpect of the Sphere in which they were placed, it was a plain Conſequence that every one of them that appeared any thing bright, muſt be larger than the Path or Orbit of the Earth: which is very abſurd. This is the principal Argument that Tycho Brahe ſet up againſt Copernicus. But when the Teleſcopes took away thoſe Rays of the Stars which appear when we look upon them with our naked Eye, (which they do beſt when the Eye-glaſs is black’d with Smoke) they ſeemed juſt like little ſhining Points, and then that Difficulty vaniſhed, and the Stars may yet be ſo many Suns. Which is the more probable, becauſe their Light is certainly their own: for it’s impoſſible that ever the Sun ſhould ſend, or they reflect it at ſuch a vaſt Diſtance. This is the Opinion that commonly goes along with Copernicus’s Syſtem. [They are not all in the ſame Sphere.] And the Patrons of it do alſo with reaſon ſuppoſe, that all theſe Stars are not in the ſame Sphere, as well becauſe there’s no Argument for it, as that the Sun, which is one of them, cannot be brought to this Rule. But it’s more likely they are ſcatter’d and diſpers’d all over the immenſe Spaces of the Heaven, and are as far diſtant perhaps from one another, as the neareſt of them are from the Sun.

Here again too I know Kepler is of another Opinion in his Epitome of Copernicus’s Syſtem, that we mention’d above. For tho’ he agrees with us, that the Stars are diffus’d through all the vaſt Expanſe of the Heavens, yet he cannot allow that they have as large an empty Space about them as our Sun has. For then ’twas his Opinion, we ſhould ſee but very few, and thoſe of very different Magnitudes: For, ſeeing the largeſt of all appear ſo ſmall to us, that we can ſcarce obſerve or meaſure them with our beſt Inſtruments; how muſt thoſe appear that are three or four times farther from us? Why, ſuppoſing them no larger than theſe, they muſt ſeem three or four times leſs, and ſo on ’till a little farther they will not be to be ſeen at all: Thus we ſhall have the ſight of but very few Stars, and thoſe very different one from another; Whereas we have above a Thouſand, and thoſe not conſiderably bigger or leſs than one another. But this by no means proves what he would have it; and his Miſtake was chiefly, that he did not conſider the Nature of Fire and Flame which may be ſeen at ſuch diſtances, and at ſuch ſmall Angles as all other Bodies would totally diſappear under. A thing that we need go no farther than the Lamps ſet along the Streets to prove. For altho’ they are a hundred Foot from one another, yet you may count Twenty of them in a continued Row with your Eyes, and yet the twentieth Part of them ſcarce makes an Angle of ſix Seconds. Certainly then the glorious Light of the Stars muſt do much more than this; ſo that it’s no wonder we ſhould ſee a Thouſand or two of them with our bare Eyes, and with a Teleſcope diſcover twenty times that number. But Kepler had a private Deſign in making the Sun thus ſuperiour to all the other Stars, and planting it in the Middle of the World, attended with the Planets: For his Aim was hereby to ſtrengthen his Coſmographical Myſtery, that the Diſtances of the Planets from the Sun are in a certain proportion to the Diameters of the Spheres that are inſcribed within, and circumſcribed about Euclid’s Regular Bodies. Which could never be ſo much as probable, except there were but one Chorus of Planets moving round the Sun, and ſo the Sun were the only one of his kind.

But that whole Myſtery is nothing but an idle Dream taken from Pythagoras or Plato’s Philoſophy. And the Author himſelf acknowledges that the Proportions do not agree ſo well as they ſhould, and is fain to invent two or three very ſilly Excuſes for it. And he uſes yet poorer Arguments to prove that the Univerſe is of a ſpherical Figure, and that the Number of the Stars muſt neceſſarily be finite, becauſe the Magnitude of each of them is ſo. But what is worſt of all is, that he ſettles the Space between the Sun and the Concavity of the Sphere of the fix’d Stars, to be ſix hundred thouſand of the Earth’s Diameters. For this reaſon, which he has no Foundation for, that as the Diameter of the Sun is to that of the Orbit of Saturn, which he makes to be as 1 to 2000, ſo is this Diameter to that of the Sphere of the fixed Stars. I cannot but wonder how ſuch things as theſe could fall from ſo ingenious a Man, and ſo great an Aſtronomer. But I muſt be of the ſame Opinion with all the greateſt Philoſophers of our Age, that the Sun is of the ſame Nature with the fix’d Stars. And this will give us a greater Idea of the World, than all thoſe other Opinions. [The Stars have Planets about them like our Sun.] For then why may not every one of theſe Stars or Suns have as great a Retinue as our Sun, of Planets, with their Moons, to wait upon them? Nay, there’s a manifeſt reaſon why they ſhould. For if we imagine our ſelves placed at an equal diſtance from the Sun and fix’d Stars; we ſhould then perceive no difference between them. For, as for all the Planets that we now ſee attend the Sun, we ſhould not have the leaſt glimpſe of them, either becauſe their Light would be too weak to affect us, or that all the Orbs in which they move would make up one lucid Point with the Sun. In this Station we ſhould have no occaſion to imagine any difference between the Stars, and ſhould make no doubt if we had but the Sight, and knew the Nature of one of them, to make that the Standard of all the reſt. We are then plac’d near one of them, namely, our Sun, and ſo near as to diſcover ſix other Globes moving round him, ſome of them having others performing them the ſame Office. Why then may not we make uſe of the ſame Judgment that we would in that caſe; and conclude, that our Star has no better attendance than the others? So that what we allowed the Planets, upon the account of our enjoying it, we muſt likewiſe grant to all thoſe Planets that ſurround that prodigious number of Suns. They muſt have their Plants and Animals, nay and their rational Creatures too, and thoſe as great Admirers, and as diligent Obſervers of the Heavens as our ſelves; and muſt conſequently enjoy whatſoever is ſubſervient to, and requiſite for ſuch Knowledge.

What a wonderful and amazing Scheme have we here of the magnificent Vaſtneſs of the Univerſe! So many Suns, ſo many Earths, and every one of them ſtock’d with ſo many Herbs, Trees, and Animals, and adorn’d with ſo many Seas and Mountains! And how muſt our Wonder and Admiration be increaſed when we conſider the prodigious Diſtance and Multitude of the Stars?