Department of History
University of California, Irvine
 Instructor:    Dr. Barbara J. Becker

Week 5.  The Age of Enlightenment.

excerpts from
An Original Theory or New Hypothesis of the Universe (1750)
by Thomas Wright (1711-1786)

Letter the Seventh
The Hypothesis, or Theory, fully explained and demonstrated, proving the sidereal Creation to be finite.

...As I have said before, we cannot long observe the beauteous Parts of the visible Creation, not only those of this World on which we live, but also the Myriads of bright Bodies round us, with any Attention, without being convinced, that a Power supreme, and of a Nature unknown to us, presides in, and governs it....

And notwithstanding the many wonderful Productions of Nature in this our known Habitation, yet the Earth, when compared with other Bodies of our own System, seems far from being the most considerable in it; and it appears not only very possible, but highly probable, from what has been said, and from what we can farther demonstrate, that there is as great a Multiplicity of Worlds, variously dispersed in different Parts of the Universe, as there are variegated Objects in this we live upon.  Now, as we have no Reason to suppose, that the Nature of our Sun is different from that of the rest of the Stars; and since we can no way prove him superior even to the least of those surprising Bodies, how can we, with any Shew of Reason, imagine him to be the general Center of the whole, i.e. of the visible Creation, and seated in the Center of the mundane Space?  This, in my humble Opinion, is too weak even for Conjecture, their apparent Distribution, and irregular Order argue so much against it.

The Earth indeed has long possessed the chief Seat of our System, and peaceably reigned there, as in the Center of the Universe for many Ages past; but it was human Ignorance, and not divine Wisdom, that placed it there; some few indeed from the Beginning have disputed its Right to it, as judging it no way worthy of such high Eminence.  Time at length has discovered the Truth to every body, and now it is justly displaced by the united Consent of all its Inhabitants, and instead of being thought the most majestick of all Nature's lower Works, now rather disgraces the Creation, so much it is reduced in its present State from what it had Reason to expect in the former.

Now it is no longer the only terrestrial Globe in the Universe, but is proved to be one of the least Planets of the solar System, and surprizingly inferior to some of its Fellow Worlds.  The Sun, or rather the System, has almost as long usurped the Center of Infinity, with as little Pretence to such Pre-heminence; but now, Thanks to the Sciences, the Scene begins to open to us on all Sides, and Truths scarce to have been dreamt of, before Persons of Observation had proved them possible, invades our Senses with a Subject too deep for the human Understanding, and where our very Reason is lost in infinite Wonders.  How ought this to humble every Mind susceptible of Reason!....

[W]e may readily imagine ... that ... as the Planets would, if viewed from the Sun, there may be one Place in the Universe to which [the stars'] Order and primary Motions must appear most regular and most beautiful.  Such a Point, I may presume, is not unnatural to be supposed, although hitherto we have not been able to produce any absolute Proof of it.

This is the great Order of Nature, which I shall now endeavour to prove, and thereby solve the Phænomena of the Via Lactea; and in order thereto, I want nothing to be granted but what may easily be allowed, namely, that the Milky Way is formed of an infinite Number of small Stars.

Let us imagine a vast infinite Gulph, or Medium, every Way extended like a Plane, and inclosed between two surfaces, nearly even on both Sides, but of such a Depth or Thickness as to occupy a Space equal to the double Radius, or Diameter of the visible Creation, that is to take in one of the smallest Stars each Way, from the middle Station, perpendicular to the Plane's Direction, and, as near as possible, according to our Idea of their true Distance.

But to bring this Image a little lower, and as near as possible  level to every Capacity, I mean such as cannot conceive this kind of continued Zodiack, let us suppose the whole Frame of Nature in the Form of an artificial Horizon of a Globe, I don't mean to affirm that it really is so in Fact, but only state the Question thus, to help your Imagination to conceive more aptly what I would explain.  Plate XXIII will then represent a just Section of it.

Plate XXIII (above; erroneously labelled Plate XXI).  This drawing shows a small portion of the shell of stars depicted in Plate XXVII (below).  Point A in each illustration represents an observer who sees many stars (the Milky Way) when looking toward point E, but fewer stars when looking toward either point B or C.

Now in this Space let us imagine all the Stars scattered promiscuously, but at such an adjusted Distance from one another, as to fill up the whole Medium with a kind of regular Irregularity of Objects.  And next let us consider what the Consequence would be to an Eye situated near the Center Point, or any where about the middle Plane, as at the Point A.

Is it not, think you, very evident, that the Stars would there appear promiscuously dispersed on each Side, and more and more inclining to Disorder, as the Observer would advance his Station towards either Surface, and nearer to B or C, but in the Direction of the general Plane towards H or D, by the continual Approximation of the visual Rays, crowding together as at H, betwixt the Limits D and G, they must infallibly terminate in the utmost Confusion.  If your Opticks fails you before you arrive at these external Regions, only imagine how infinitely greater the Number of Stars would be in those remote Parts, arising thus from their continual crowding behind one another, as all other Objects do towards the Horizon Point of their Perspective, which ends but with Infinite:  Thus all their Rays at last so near uniting, must meeting in the Eye appear, as almost, in Contact, and form a perfect Zone of Light; this I take to be the real Cause, and the true Nature of our Milky Way, and all the Irregularity we observe in it at the Earth, I judge to be intirely owing to our Sun's Position in this great Firmament, and may easily be solved by his Excentricity, and the Diversity of Motion that may naturally be conceived amongst the Stars themselves, which may here and there, in different Parts of the Heavens, occasion a cloudy Knot of Stars, as perhaps at E.

But now to apply this Hypothesis to our present Purpose, and reconcile it to our Ideas of a circular Creation, and the known Laws of orbicular Motion, so as to make the Beauty and Harmony of the Whole consistent with the visible Order of its Parts, our Reason must now have recourse to the Analogy of Things.

It being once agreed, that the Stars are in Motion..., we must next consider in what Manner they move.  First then, to suppose them to move in right [straight] Lines, you know is contrary to all the Laws and Principles we at present know of; and since there are but two Ways that they can possibly move in any natural Order, that is, either in right Lines, or in Curves, this being one, it must of course be the other, i.e. in an Orbit; and consequently, were we able to view them from our middle Position, as from the Eye seated in the Center of Plate XXV. we might expect to find them separately moving in all manner of Directions round a general Center, such as is there represented.

It only now remains to shew how a Number of Stars, so disposed in a circular Manner round any given Center, may solve the Phænomena before us.  There are but two Ways possible to be proposed by which it can be done, and one of which I think is highly probable....

The first is in the Manner I have above described, i.e. all moving the same Way, and not much deviating from the same Plane, as the Planets in their heliocentric Motion do round the solar Body....

The second [and my preferred] Method of solving this Phænomena, is by a spherical Order of the Stars, all moving with different Direction round one common Center, as the Planets and Comets together do round the Sun, but in a kind of Shell, or concave Orb....

Plate XXIV.  A Representation of the Convexity ... of the intire Creation, as a universal Coalition of all the Stars consphered round one general Center, and as all governed by one and the same Law.

Plate XXV.  A central Section of the same, with the Eye of Providence seated in the Center, as in the virtual Agent of Creation....

Plates XXXI (above) and XXXII (below) show the universe filled with many systems like our own, each a star-filled shell surrounding its own "eye of Providence."

Thus, Sir, you have had my full Opinion, without the last Reserve, concerning the visible Creation, considered as Part of the finite Universe; how far I have succeeded in my designed Solution of the Via Lactea, upon which the Theory of the Whole is formed, is a Thing will hardly be known in the present Century, as in all Probability it may require some Ages of Observation to discover the Truth of it....

Letter the Eighth
Of Time and Space, with regard to the known Objects of Immensity and Duration.

...I will try by some less mathematical Method than that of meer Numbers, to imprint an Idea in your Mind of the true Extent of the solar System, and the magnitude of all its moving Bodies, by natural Objects most familiar to your Senses....

Modern Astronomers have made use of the swiftest Velocity of a Cannon-Ball as continued thro' the Space they would so describe, and in this Light, the Distance to the Sun has been by many compar'd to twenty-five Years Motion of a Cannon-Ball, supposing it to travel at the Rate of 100 Fathom in a Moment, i.e. the Pulse of an Artery; and that a Journey so performed to one of the nearest fix'd Stars, would take the same Body at least 100,000 Years before it could arrive there.

But the Method I have chose to convey my Ideas of the Magnitude of the planetary Bodies, and the Extent of the visible Creation to you, I am willing to hope you will find still more familiar, comprehensive, and easy:  And it only depends upon your Remembrance of a very few known Objects, and their neighbouring Distances, which may be presumed you are, or have been very well acquainted with.  You have not only very lately but very often been in London, and must, I think, retain some Idea of the Dome of St. Paul's, tho' I own I ought not to be sorry if you should chance to have forgot it, provided it might prove a Means of making your Visits more frequent.  The Diameter of the Dome of this Church is 145 Feet:  Now if you can imagine this to represent the Surface of the Sun, a spherical Body 18 Inches diameter, will justly represent the Earth in like Proportion; and another of only five Inches diameter, will represent the Moon....

From the Magnitude of the Earth on which we live, as from a known Scale with respect to its Parts compared with our own Bodies, we naturally frame our first Ideas of Extent, and fix our Rationale of Remoteness; by which we are sufficiently enabled to judge of all other sensible Distances within one finite view.  And hence by the undoubted Principles of Geometry, having first given the Measurement of the Earth in any known Proportion with any other Quantity most familiar to our Senses, and the Angle of Appearance, or Parallax to any perceivable Object, we can easily find in homogenial Parts its true Distance from the Eye.  And thus allowing for some small tho' unavoidable Errors, that may possibly arise from the Difficulties of Observations (especially small Angles and minute Quantities) we can always determine to a sufficient, and very frequently to a just Exactness, the relative Distance of all visible Bodies, remote or near, such as the Planets, Comets, and the Sun....

The Sun is found to be mean distant from the Earth nearly 81 Millions of Miles, or 6877.5 Diameters of the Earth; and Saturn, the remotest Planet from him is at his greatest Distance from us about 858 Millions of Miles:  Yet these Distances are but the beginning of Space, and only serve to open our Ideas for farther Search....

[W]e may reasonably suppose, that the nearest Star can be no nearer than a triple Radius of its active Sphere; and provided they are all in regular Order, and much of the same Magnitude with one another (which no Arguments can possibly contradict) this Radius we may justly make 2000 times the Distance of our Earth.  For admitting the utmost Limits of the Sun's Attraction to exceed this Sphere of the Comets, as far as the Sphere of the Comets exceeds that of the Planets, which is nearly 14.4 times, the Radius of the solar System will be extended every way 200 Radius's of the Orbit of Saturn, and consequently the Distance from Star to Star will not be less than 6000 times the Radius of our Orbis Magnus, and consequently upwards of 480,000,000,000 Miles.  That this is even less than the real Truth, and may be defended as a very moderate Computation, grounded upon Reason, we have infallible Demonstration to witness....

[T]o pass from any one Star to another, we must fly thro' so vast a Tract of pure Expanse or Ether, that to visit any one of the most neighbouring Systems, could we travel even as fast as the swiftest Eagle flies, for Instance, 500 Miles per Day, yet should we be 3,000,000 of Years upon our way before we could arrive there; and if continuing on to view the Regions of the rest within the known Creation, Myriads of Ages would be spent, and yet we could not hope to see the whole of but the smallest Constellation.

But what Idea of Distance can you receive from this sort of Estimation, where Numbers arise so very high.  I own to you mine are soon quite lost by this Method of counting, either, Distances or Duration.  I believe few People can range their Ideas with such Perspecuity, as to arrive at any adequate Notion of any Number above a thousand.

To give you therefore a clearer Idea of Distance, and impress the Proportions of Space more strongly and fully in your Mind, let us suppose the Body of the Sun, as I have said before, to be represented by the Dome of St. Paul's; in such Proportion a spherical Body eighteen Inches Diameter, moving at Mary-le-bone, will justly represent the Earth, and another of five Inches Diameter, describing a Circle of forty-five Feet and a half Radius round it, will represent the Orbit and Globe of the Moon.

London area landmarks illustrate the scale of the solar system.

A Body at the Tower of 9.7 Inches, will represent Mercury; and one of 17.9 Inches at St. James's Palace will represent the Planet Venus; Mars may be supposed at a Distance, like that of Kensington or Greenwich, 10 Inches Diameter; Jupiter, imagined to be at Hampton-Court, or Dartford in Kent; and Saturn, at Cliefden, or near Chelmsford:  The first represented by a Globe 15 Foot 4 Inches Diameter, the latter by one of 11 Feet 1/2 and his Ring four Feet broad:  These would all naturally represent the planetary Bodies of our System in their proper Orbits and proportional Magnitudes, as moving round the Cupola of St. Paul's, as their common Center the Sun.  And preserving the same natural Scale, the Aphelion of the first Comet would be about Bury, the second at Bristol, and the third near the City of Edinburgh.  But if you will take into your Idea one of the nearest Stars; instead of the Dome of St. Paul's, you must suppose the Sun to be represented by the gilt Ball upon the Top of it, and then will another such upon the Top of St. Peter's at Rome represent one of the nearest Stars....

Such vast room in Nature, as Milton finely expresses it, cannot be without its Use; and nothing but absolute Demonstration is wanting (which from their Nature and Distance cannot be expected) to confirm the grand Design, so suited to the Deity's infinite Capacity, and of eternal Benefit to all his Creatures, especially Beings of a rationale Sense, and in particular Mankind.

Of these habitable Worlds, such as the Earth, all which we may suppose to be also of a terrestrial or terraqueous Nature, and filled with Beings of the human Species, subject to Mortality, it may not be amiss in this Place to compute how many may be conceived within our finite View every clear Star-light Night.

It has already been made appear, that there cannot possibly be less than 10,000,000 Suns, or Stars, within the Radius of the visible Creation; and admitting them all to have each but an equal Number of primary Planets moving round them, it follows that there must be within the whole celestial Area 60,000,000 planetary Worlds like ours.  And if to these we add those of the secondary Class, such as the Moon, which we may naturally supposed to attend particular primary ones, and every System more or less of them as well as here; such Satellites may amount in the Whole perhaps to 100,000,000, or more, in all together then we may safely reckon 170,000,000, and yet be much within Compass, exclusive of the Comets which I judge to be by far the most numerous Part of the Creation.

In this great Celestial Creation, the Catastrophy of a World, such as ours, or even the total Dissolution of a System of Worlds, may possibly be no more to the great Author of Nature, than the most common Accident in Life with us, and in all Probability such final and general Doom-Days may be as frequent there, as even Birth-Days, or Mortality with us upon the Earth.

This Idea has something so chearful in it, that I own I can never look upon the Stars without wondering why the whole World does not become Astronomers; and that Men endowed with Sense and Reason, should neglect a Science they are naturally so much interested in, and so capable of inlarging the Understanding, as next to a Demonstration, must convince them of their Immortality, and reconcile them to all those little Difficulties incident to human Nature, without the least Anxiety....

Go to:
  • The World, or Treatise on Light (1629-1633), by Réné Descartes (1596-1650)
  • The Description of a New World, Called The Blazing World (1666), by Margaret Cavendish, Duchess of Newcastle (1623-1673)
  • Conversations on the Plurality of Worlds (1686), by Bernard le Bovier de Fontenelle (1657-1757)
  • Micromegas:  A Tale of Interplanetary Travel (1752), by Voltaire (François Marie Arouet; 1694-1778)
Weekly Readings
Lecture Notes