Scene 4.

THE SOLAR SYSTEM.

This displays the whole Copernican or Solar System, with every planet and satellite in diurnal and annual motion! With awe and deference I offer this daring but humble transcript of creation! Enough, if one idea can be added, to the ingenuous mind, of the attributes and perfections of the Deity.

The Sun, a huge globe of fire (957,942 miles diameter, and consequently a million times as large as our Earth, and intended to give light, heat, and vegetation, to seven primary and at least eighteen secondary worlds) is placed in the centre of the system; and by spots on his disk is discovered to turn on his axis in about 25 of our days. These spots cannot be permanently fixed, because they are frequently altering in their shape, situation, number, &c. tho’ some have supposed they have seen small indentations on the edge of the Sun, as the spots have passed it, and conjectured that a fluid matter surrounded a dark nucleus, which sometimes becoming bare, might occasion the transient appearance and disappearance of the spots.

Mercury is the first planet in the order of the system; about 3498 miles diameter: he moves round the Sun with the greatest velocity of any of the Planets familiar to our system (as being nearest the Sun) in about 88 of our days; at the rate of 110,680 English miles every hour, but the angle of his distance from the Sun, as seen by us, is so small, that unless by the telescope, we can seldom discern him[2]; (and even then an equatorial instrument to direct to its place, as indicated by the Ephemeris, will be requisite;) and when we do, it is for so short a time, and in twilight, that we can discover no spots on his face, and therefore to this hour know nothing of the length of his days and nights: we see him partially enlightened like the Moon, sometimes like a small crescent, in other situations half enlightened, and sometimes gibbous or oval, and are therefore certain he derives his light from the Sun, as she does: so that no doubt he is a fellow world, with inhabitants adapted to the heat of his situation: altho’ this heat is seven times as great as that of the Earth. He is not much larger than the Moon. Our Earth, viewed from Mercury, must appear much larger and more luminous than any of the Planets, except Venus, appears to us.

Venus is the next planet in the order of the system, and distinguished by her superior brilliancy, as the Sun’s light is twice as great to this planet as to the Earth; from this cause she is sometimes visible to the naked eye in full day-light. She is about 70 millions of miles from the Sun, or about twice the distance of Mercury; and like him, but much longer and more conspicuously, appears under the different phases of the Moon. These, as we have said, are proofs that both planets borrow their light from the Sun. The orbits of these planets (as well as those of the rest of the system) are inclined to the orbit of the Earth. Hence when Venus and Mercury are found in the nodes of their orbits between the Earth and Sun, they are transferred upon the Sun’s face like small round black spots, and which in fact are partial Eclipses of the Sun; these are called the transits of Mercury, or Venus.

Venus is a little larger than the Earth, or 9360 miles diameter; and moves round the Sun in 224½ of our days, at the rate of 80,955 miles every hour. From faint spots seen upon her surface, Mr. Shroeter apprehends she revolves on her axis in 23 hours, 21 minutes; that her surface is irregular like that of the Moon, and some of her mountains four miles high. The atmosphere of Venus has been calculated to be 50 miles high: and the Sun would appear to the inhabitants of this planet twice as large as to us. When Venus is to the west of the Sun, she is a morning star; when to the east of him, an evening star: her orbit or track is included by the Earth’s, and as both move the same way, she appears to be on one side of the Sun longer than the 224½ days she is in going round him. The axis of Venus is said by some astronomers to incline 75 degrees to the axis of her orbit: and therefore her seasons vary very fast, the Sun passing over more of her from pole to pole in one day, than over the Earth in a quarter of a year. Hence the heated places of this planet have time to cool: which suggest to our ideas that provision has been made for inhabitants, that they might not suffer by their vicinity to the Sun; this circumstance also gives her two winters and two summers at her equator, and indicates her inhabited. The discovery lately made by Mr. Shroeter, of a light faintly extended beyond the bounds of direct solar illumination, when she has her falcated appearance like the Moon near to her change, strengthens this probability: as these are signs of twilight, and of an atmosphere. This astronomer has also observed her to have considerable mountains; another character of a globe suited for habitation.

The Earth is the third planet in the order of the system: 8244 miles diameter—moves at the rate of 68,856 miles every hour, and hence completes its revolution in its orbit (the Ecliptic) in 365 days and ¼. The Moon’s diameter is 2183 miles; she moves with respect to the Earth 2290 miles in her orbit every hour; and goes round the Earth from change to change in 29 days and a half. But having devoted so much of this tract to the phænomena of the Earth, as well as its satellite the Moon, we proceed to

Mars, known in the heavens by his peculiarly red appearance, arising from a very thick and dense atmosphere. This Planet is next above the Earth, and hence has considerable less light from the Sun than we have; is much smaller than the Earth, or about 4470 miles diameter. He is near 150 millions of miles from the Sun, and goes round him in something less than two of our years, moving at the rate of 55,783 miles every hour. His day and night is rather longer than ours, or 24h. 39m. 22s. and uniform throughout his year, so that his axis being perpendicular, he has no variety of seasons. When we pass between the Sun and him he has a most fiery and alarming appearance, and is often mistaken for a Comet; but when we are on the opposite side of our orbit, he appears small, and scarcely to be distinguished from a fixed star.

Jupiter, far the largest of our Planets, near 1300 times the size of the Earth, or 93,333 miles diameter, is the next above Mars, at five times the distance from the Sun that we are; so that he enjoys but a twenty-fifth part of the light, heat, and attraction of that luminary we do.—Though indeed of the light and heat he may still possess, we are not so certain as of the degree of attraction: that being invariably proportioned to the distance; while these will be relative to the density and other circumstances of the atmosphere, and the aptness of the surface of the Planet to acquire and retain heat: after Venus he appears the most brilliant Planet of the Universe. He is attended with four satellites that revolve very regularly round him. The three first are eclipsed every revolution, and every seventh day come in conjunction with him and one another, as may be seen on the Eidouranion. Longitude, at land, can be ascertained by the eclipses of Jupiter’s satellites, as well as by a transit of Venus; and these would supercede the necessity of a time-keeper, if they could be observed at sea; hence, in the Nautical Almanack, these eclipses are very exactly calculated for the meridian of Greenwich, and answer very good geographical as well as nautical purposes. Jupiter is near twelve years in making his way round the Sun, altho’ he moves at the rate of 30,193 miles every hour; he turns round his axis in about ten of our hours, so that his days and nights are but five hours each: and he has no variety of seasons; for his axis is perpendicular to the plane of his orbit. Turning so swiftly on his axis, his figure becomes more oblate than that of the Earth, being more than 6000 miles longer in diameter from one side of his equator to the other, than from pole to pole, or in the proportion of 13 to 14.[3] This swiftness of his diurnal motion also draws his clouds and vapours into streaks or lines over his equatorial parts, forming what are called Jupiter’s Belts. An eclipse of the Sun, by this great planet, would be a striking object even to the unassisted sight as viewed from Saturn.

Saturn, 85,782 miles in diameter or about 1000 times as large as the Earth, is still a more remote planet from the Sun, round which he revolves in about 30 of our years, at the distance of 916 millions of miles. He moves in his orbit at the rate of 22,298 miles every hour, and upon his axis in 10h. 16m. by this swift revolution on his axis his figure becomes oblate in the proportion of 11 to 10, and his atmosphere and vapours are drawn like a quintuple belt of 3 darker parts and 2 lighter upon his body. Saturn is attended by seven Satellites, the outermost has been long known to have a period of apparent augmentation and diminution, and hence probably to have a revolution on its axis, and be composed of land and water.

A large, broad, double, and luminous ring of 200,157 miles diameter, surrounds Saturn, at a distance from the planet equal to the breadth of the ring.—This ring inclines about 30 degrees to the plane of the ecliptic, and must appear like a great arch of light to the inhabitants of Saturn. It has a revolution every eleven hours on an axis perpendicular to its plane, and keeps parallel to itself at all times; hence it disappears twice every 30 years, when its edge is presented to us; the Sun shines for near 15 of our years together on the northern plane of the ring; and then leaving it, illumines the southern side for the same period; so there is but one day and one night on each side of the ring, but each will be of 15 years continuance without intermission.

The Sun’s direct light being but about a 90th part so strong to Saturn as to the Earth, this ring is no doubt intended to increase it, by reflecting a very considerable portion upon the planet, which added to that from his seven Satellites, must render him a very comfortable abode for rational and brute inhabitants.

The Georgium Sidus, or Georgian Planet (so called by Dr. Herschell, its ingenious and indefatigable discoverer) makes the seventh in the order of the system; the other planets we have described have been known as such to the highest antiquity, but from its extreme smallness, this has escaped ascertainment till the year 1781, although it had been recognized as a very minute star by several astronomers. It is near twice Saturn’s distance from the Sun, and will be near eighty-two years and six months in going round him; is of a pale colour, and much larger in its telescopic appearance than the fixed stars, being 100 times as large as the Earth, or 37,230 miles diameter, and, on a clear evening, is visible to the naked eye. The Dr. has discovered six satellites to this planet, some of which are said to move retrograde. As familiarity is the principal design of this Treatise and Lecture, it may be useful to exhibit the distances of the planets from the Sun in the most concise form, and in numbers they will stand thus:—if the distance from the Sun of

Mercury—Venus—Earth—Mars—Jupiter—Saturn—Georgium Sidus
is 4will be 710155295190

or, if a body projected from the Sun should continue to fly at the rate of 480 miles per hour, (which is about the swiftness of a cannon-ball), it could reach the orbit of Mercury in 9 years, Venus in 16 years, the Earth in 23 years, Mars in 34 years, Jupiter in 118 years, Saturn in 216 years, and the Georgium Sidus in 432 years.

These we consider as the regular bodies of our system; so regular, indeed, that every phænomenon respecting them is calculated for years before hand, and it is almost considered as a criminal error to be a minute of time wrong in the calculation. But we are sometimes visited by Comets, which may also be recognized as a part of our system: of these our knowledge is very imperfect. By supposing that the same Comet has appeared at equal intervals of time; by observing that, like the planets, they describe equal areas in equal times; and by having three points in an ellipsis given to make out its eccentricity; from these data it was natural for mathematicians to suppose they could calculate the return of all Comets that had been scientifically observed: but the actual return even of that conspicuous one expected by Dr. Halley, has been thought by some not to be sufficiently ascertained: yet, on examining the balance of probability, as stated by Maupertius, Lalande, Messire and Martin, for its re-appearance, probably this doubt will be greatly lessened, if not removed. As new Comets are almost perpetually appearing, on which calculation hitherto has been silent, there is reason to expect, in a proper period of time, an adequate number of observations to decide the question, whether in general they revolve at stated times, or traverse our system without probability of return. Perhaps Comets of each description time and observation may confirm to us. We know that Comets accompanied with tails come very near the Sun, and from all quarters of the Heavens! that the tails keep opposite to the Sun; consequently they are only visible to us when seen obliquely to the Sun. Thus the Comet of August, 1797, was observed to have little or no train during any part of its appearance; but a faint hazy light diffused round it; these trains, like electrical and borealean light, do not refract the light of the fixed stars, &c. The appearance of the Comet of 1682, is copied in the Eidouranion. It descends from the top of the Machine; its train increasing in length and lustre till it arrives at the Sun, diminishing as it ascends. Its orbit is so eccentric that the small part of it visible is not sensibly to be distinguished from the parabolic curve; and in this representation it finally disappears in the roof of the Theatre; it being impossible, if its return were ascertained, to represent the extent of such an orbit, and its motion in it, with any degree of suitable proportion. The velocity of such of these as approach nearest to the Sun, particularly of the Comet of 1680, (whose appearance was tremendous) exceeds any swiftness that falls within observation; except that of the rays of light; it being nearly 2000 times greater than the swiftness of a cannon-ball, at the instant of its discharge; yet scarcely a thousandth part of the velocity of light passing from the Sun[4]. This Comet approached to within 40,000 miles of the Sun’s surface, and was calculated to be heated 2000 times hotter than red hot iron; a globe of iron the size of the Earth in this heat, would be 50,000 years in cooling. These amazing visiters, whom philosophy contemplates with awe very different from that terror with which superstition had long viewed them, moving in such amplitude of space, so numerous as they are, and so great as some of them, must have functions assigned to them proportionally important: either occasionally of terrific revolution; or more generally of recruiting the atmosphere of the planets in their successive appulse to any of them, and supplying the diminution of the solar fires. Perhaps too they are useful in preventing the central tendency of the planets to the Sun, from increasing more than in a certain degree; so that the apparent disturbances, thus produced, will be part of the necessary order and harmony of the system.

It is probable (though their orbits are so much oblique in all directions to those of the planets, that it can rarely happen) that Comets may be instrumental to great shocks; either by direct collision, the effect of which, considering the velocity and mass of some of them cannot be estimated, or by near approach: and of this latter a possible result, and such as seems, in one instance at least, to have already taken place, is noticed in the Remarks annexed to this account of the Eidouranion. But the philosophic observer will have this reflection presented to him from the phænomena of the Universe; that the apparently disturbing and destructive powers are secondary and subservient; while those of the preserving and meliorating kind are primary, continued, and universal. And those incidental causes of a melancholy and distressing aspect, when resolved into their ultimate tendency and necessary effects, manifest themselves, in so far as we can trace them, to be parts essential to the system of pure and perfect benevolence. Stability and duration are stamped on the Universe, and the imagination is lost in the immensity of the prospects; and whether we turn to the past or to the future, our conception vainly pants to grasp the idea of boundless Eternity.

But when we launch in idea into infinite space, and contemplate the systems without number that fill it; here indeed we have a subject truly worthy of the Deity! Whoever supposes the fixed stars placed in a concave sphere, as they appear to us, must have a narrow and contracted idea of the Supreme Being; for one star appears large and another small, because one is immensely distant from us in comparison of another. Through Dr. Herschell’s large telescope many fixed stars appear double: the Polar star is double; (but they are only stars at different distances from us appearing nearly in the same line) some appear like a topaz, others azure, others red; all are round, and many as perfectly defined as a shilling is on black cloth. By telescopes we formerly could see three times the number we can by the naked eye; and now, telescopes having received further improvement, in the most crouded part of the milky way, 116,000 have passed before the instrument in a quarter of an hour. The Nebula of Andromeda must be composed of the united lustre of many millions of stars. Agreeably to this, Dr. Herschell has noticed single nebulous stars surrounded with a faint equable whiteness; such as a system of Planets viewed at that distance from us might be supposed to give: others he has seen, which have the appearance of yet unformed systems. And there are, we may presume, points of view, in the immensity of the Universe, in which all the fixed stars, accessible to the eye or telescope from this station of ours, and all the inconceivable space, through which they extend, vanish into a nebula, and almost an indiscernible point. Such is the order and greatness of that Empire, which these Discoveries, the farther they are pursued, must for ever more and more present to our increasing admiration. Such the relation of parts so astonishingly remote! Such the unity of intelligence, power, and preserving goodness which pervades the whole! And why may not stars be so remote, that their light may not have reached the Earth even since the creation! We know that light takes more time in travelling from the nearest stars to us, than we in making a West India voyage, (which is usually performed in six weeks) a sound would not arrive to us from thence in 50,000 years, nor a cannon-ball in a much longer time. The Sun’s light could not therefore reach the fixed stars, and be reflected back again with their lustre; of course they shine by their own light—if so, they shine as our Sun, and consequently are Suns themselves.—Now, as a principal of uniformity runs through the variety of nature, it is reasonable to conclude these Suns to be centres of systems like ours; and destined for the same noble purposes, viz. that of giving light, heat, and vegetation, to various worlds that revolve round them, but which are too remote for discovery, even with our best telescopes! This idea is infinitely too great for the human mind; or indeed for that of any created Being! For how inadequate must the utmost stretch of finite faculties be to represent infinity! The stars, disposed in constellations, and surrounded by concentric circles, may perhaps assist the imagination a little: The attempt in Scene V. if not admired, we hope will be forgiven. But was it possible we could actually take our flight into infinite space, or be borne on the wings of lightning, to the most distant fixed Star we can now see, even there, perhaps, we should find ourselves on the confines of creation, and see as many stars before us as we left behind! For space has neither top nor bottom in it: it is a circle whose centre is every where, but whose circumference is no where! Even systems themselves may have revolutions round one another; and account for that difference of distance that we are constantly observing to arise amongst the fixed stars; for new stars appear, rise into magnitude, and then diminish and disappear, which would also be accounted for by supposing that our Sun himself is in progressive motion towards some part of infinite space, and carrying his system of worlds along with him. Stars of the first magnitude, in Flamsted’s time, dwindle into those of the third or fourth, in our time. Some of the stars change their magnitude periodically: as Algol, in Medusa’s Head, which rises from the third magnitude to the second, in two days and twenty-one hours.—Where such periodical disappearances are short, they have been referred with probability to quick revolutions of such stars on their axis, with part of their disk opaque; or to the regular intervention of some very considerable Planet to intercept them from us. But re-appearances of this kind, after very long intervals, would indicate rather a revolution in a great orbit. By analogy we conclude, that at a proper distance our Sun would dwindle into a fixed Star among the rest, and his system of worlds disappear. Now as we see that almost every particle of our globe swarms with life and animals, we cannot suppose the other bodies of our system to be only intended as a faint spangle for mortals to gaze at; more especially as they are as well calculated for inhabitants as ours, revolving as regularly round the same Sun, and seeming to have every other convenience for rational and brute inhabitants[5]. But to carry this idea into infinite space; to recognize Suns and Systems, above us, below us, to the East, the West, the North, the South; to consider each Sun as the centre of a system like ours, and every world inhabited!—In short, the astonished fancy turns round, and is entirely lost and sunk in the abyss of nature! Well might the Psalmist say, that, “The heavens declare the glory of God, and the firmament sheweth his handy work.” Well might he express himself as overwhelmed with the idea of the power and omnipresence of the Deity; since all our discoveries serve only to convince us, that a progress of inexpressible extent, continued through ages without number, would find us every where, as here, surrounded with his infinite energy, eternity, and immensity, filled with his vital presence.