Page:Encyclopædia Britannica, first edition - Volume I, A-B.pdf/518

 ( 434 )

ASTRONOMY.

ASTRONOMY is the cience which treats of the nature and properties of the heavenly bodies.

I.

By atronomy we dicover that the earth is at o great a ditance from the un, that if een from thence it would appear no bigger than a point, although its circumference is known to be 25,020 miles. Yet that ditance is o mall, compared with the earth's ditance from the fixed tars, that if the orbit in which the earth moves round the un were olid, and een from the nearet tar, it would likewie appear no bigger than a point, although it is at leat 162 millions of miles in diameter. For the earth, in going round the un, is 162 millions of miles nearer to ome of the tars at one time of the year than at another; and yet their apparent magnitudes, ituations, and ditances from one another till remain the ame; and a telecope which magnifies above 200 times does not enibly magnify them; which proves them to be at leat 400 thouands times farther from us than we are from the un.

It is not to be imagined that all the tars are placed in one concave urface, o as to be equally ditant from us; but that they are cattered at immene ditances from one another through unlimited pace. So that there may be as great a ditance between any two neighboring tars, as between our un and thoe which are nearet to him. Therefore an oberver, who is nearet any fixed tar, will look upon it alone as a real un; and consider the ret as o many hining points, placed at equal distances from him in the firmament.

By the help of telecopes we dicover thouands of tars which are inviible to the naked eye; and the better our glaes are, till the more become viible; o that no limits can be et either to their number or their ditances.

The un appears very bright and large in comparion of the fixed tars, becaue we keep contantly near the un, in comparion of our immene ditance from the tars. For a pectator, placed as near to any tar as we are to the un, would ee that tar a body as large and bright as the un appears to us : and a pectator, as far ditant from the un as we are from the tars, would ee the un as mall as we ee a tar, diveted of all its circumvolving planets; and would reckon it one of the tars in numbring them.

The tars, being at uch immene ditances from the un, cannot poibly receive from him so trong a light as they eem to have : nor any brightnes ufficient to make them viible to us. For the un's rays mut be o cattered and diipated before they reach uch remote objects, that they can never be tranmitted back to our eyes, o as to render thee objects viible by reflexion. The tars therefore hine with their own native and unborrowed lutre, as the un does; and ince each particular tar, as well as the un, is confined to a particular portion of pace, it is plain that the tars are of the ame nature with the un.

It is noways probable that the Almighty, who always acts with infinite widom, and does nothing in vain, hould create o many glorious uns, fit for o many important purpoes, and place them at uch ditances from one another, without proper objects near enough to be benefited by their influences. Whoever imagines they were created only to give a faint glimmering light to the inhabitants of this globe, mut have a very uperficial knowledge of atronomy, and a mean opinion of the Divine Widom : ince, by an infinitely les exertion of creating power, the Deity could have given our earth much more light by one ingle additional moon.

Instead then of one un and one world only in the univere, atronomy dicovers to us uch an inconceivable number of uns, ytems, and worlds, dipered through boundles pace, that if our un, with all the planets, moons, and comets belonging to it, were annihilated, they would be no more mied, by an eye that could take in the whole creation, than a grain of and from the ea-hore: The pace they poes being comparatively o mall, that it would carce be a enible blank in the univere, although Saturn, the outermot of our planets, revolves about the un in an orbit of 4884 millions of miles in circumference, and ome of our comets make excurions upwards of ten thouand millions of miles beyond Saturn's orbit; and yet, at that amazing ditance, they are incomparably nearer to the un than to any of the tars; as is evident from their keeping clear of the attractive power of all the tars, and returning periodically by virtue of the un's attraction.

From what we know of our own ytem, it may be reaonably concluded, that all the ret are with equal widom contrieved, ituated, and provided with accommodations for rational inhabitants. Let us therefore take a urvey of the ytem to which we belong; the only one acceible to us; and from thence we hall be the better enabled to judge of the nature and end of the other ytems of the univere. For although there is almot an infinite variety in the parts of the creation which we have opportunites of examining; yet there is a general analogy running through, and connecting all the parts into one great and universal ytem.

To an attentive coniderer, it will appear highly probable, that the planets of our ytem, together with their attendants called or, are much of the