UNIVERSE, (Encycl.) As space is in its own nature every way infinite, it gives us an idea of the infinity of the universe, which can therefore be only in part comprehended by us: and that part of the universe which we can have any notion of, is that which is the subject of our senses; and of this the eye presents us with an idea of a vast extended prospect, and the appearance of various sorts of bodies disseminated through the same.
The infinite abyss of space, which the Greeks call to paq, the Latins inane, and we the universe, does undoubtedly comprehend an infinity of systems of moving bodies round one very large central one, which the Romans called sol, and we the sun. This collection of bodies is therefore properly called the solar system, and sometimes the mundane system, from the Latin word mundus the "world."
That the universe contains as many solar systems or worlds as there are what we call fixed stars, seems
reasonable to infer from hence, that our sun, removed to the distance of a star, would appear just as a star does, and all the bodies moving about it would disappear entirely. Now the reason why they disappear is, because they are opaque bodies, and too small to be seen at so great a distance, without an intense degree of light; whereas theirs is the weakest that can be, as being first borrowed, and then reflected to the eye.
But the sun, by reason of his immense bulk and intense light, which is the strongest possible, will be visible at an immense distance; but the greater the distance, the less bright it will appear, and of a lesser magnitude: and therefore every star of every magnitude may probably be a sun like our own, informing a system of planets or moving bodies; each of which may be inhabited, like our earth, with various kinds of animals, and studded with vegetable and other substances.
We can perceive, says Mr MacLaurin, no bounds of the vast expanse in which natural causes operate; nor can we fix any border or termination of the universe; and we are equally at a loss to trace things to their elements, and to discover the limits which enclose the subdivisions of matter. The objects which we commonly call great, vanish when we contemplate the vast body of the earth. The terraqueous globe itself is soon lost in the solar system; being in some parts seen as a planet or distant star, and in great part of the system unknown, or visible only at rare times to vigilant observers, assisted perhaps with instruments like our telescopes. The sun itself dwindles into a star: Saturn's vast orbit, and the orbits of all the comets, crowd into a point when viewed from numberless places between the earth and the nearest fixed stars. Other suns illuminate other systems where our sun's rays are unperceived: but all these are also swallowed up in the vast expanse of the universe. Even all the systems of the stars that sparkle in the clearest sky, must possess a small corner only of that space over which such systems are dispersed. And after we have risen so high, and left all definite measures so far behind us, we find ourselves no nearer to a term or limit; for all this is nothing to what may be displayed in the infinite expanse, beyond the remotest stars that ever have been discovered.
In this view of the universe, an august idea arises in the mind, worthy of the infinite and wise Author of nature, who can never be supposed to have created so many glorious orbs, to answer so trifling a purpose as the twinkling to mortals by night now and then; besides that the far greatest part of the stars are never seen by us at all.