Skyscript home page

The Asteroids
The Comets
The Origin of Asteroids & Comets
The Meteoroids
Raphael on Astrological Portents

Asteroids and Comets by David McCann

The Asteroids

In 1766 a German astronomer, Titius, discovered a pattern in the distances of the planets from the Sun. This is now known as 'Bodes Law', after a colleague of his who published it. Write down the sequence 0, 3, 6, 12 and so on, doubling each time; add 4 to each number; then divide by 10. The result is the distance of the planets from the Sun in astronomical units:

No. Formula Bode's Law True Distance Planet
0 +4 /10 0.4 0.4 Mercury
3 +4 /10 0.7 0.7 Venus
6 +4 /10 1 1 Earth
12 +4 /10 1.6 1.5 Mars
24 +4 /10 2.8 - ?
48 +4 /10 5.2 5.2 Jupiter
96 +4 /10 10 9.5 Saturn

As Bode remarked, something seems to be missing between Mars and Jupiter. This assumption was strengthened in 1781 when William Herschel identified Uranus at a distance of 19.2 astronomical units, very close to the predicted position after Saturn, which gives a result according to Bode's law of 19.6.

In 1800 Johann Schroeter organised a group of German astronomers, whom he nicknamed the 'Celestial Police', to hunt down the missing planet. They were beaten to it by Giuseppe Piazzi of Palermo, who found Ceres on New Year's Day 1801 - at 2.8 AU, exactly as required. But Ceres was not alone, for two other of the 'policemen' were also successful. Olbers found Pallas in 1802 and Vesta in 1807, while Harding discovered Juno in 1804. Their distances ranged from 2.0 to 2.6 AU.

In the 1840s discoveries began again, and the number has grown steadily. Nearly 4000 have now been catalogued, and there are many more. It is difficult to say just how many - how big does a lump of rock have to be before you call it an asteroid? Not all of the asteroids lie between Mars and Jupiter. Many have elongated orbits which cross the paths of Mars or Jupiter, and some even move inside the orbit of the Earth.

The trouble with asteroids from an astrologer's point of view is that there are too many of them. Ancient astrologers had seven out of ten planets, and so one might expect their interpretations to be at least 70% correct. If each asteroid had the effect of a planet, then, with nearly 4000 missing planets, a conventional chart would be worthless. On the other hand, if the traditional chart is, say, 75% complete, then each planet is over a thousand times more significant than each asteroid.

Those astrologers who employ asteroids frequently differ as to their significance. Ceres is associated with nurturing by Zipporah Dobyns, but with agriculture and the working classes by Barry Lynes. Pallas means creativity for Demetria George, 'prudent intellect' for Emma Donat, but politics for Dobyns. Vesta is dedication to work for Dobyns, service for Donat, the 'focusing of the self' for George, and domesticity for H. C. Meier. It is of course very easy to find meaning where none exists. The classic case is that of the hypothetical planets. Witte and Ram both claimed to have discovered new planets by the careful study of their transits through horoscopes. yet Witte failed to discover Rams 'planets' and Ram failed to discover Witte's; nor did Witte's work in the 1920s reveal the existence of Pluto. Even if we considered the work on asteroids to be valid, we would still have to explain how we can get results from a chart with over 99% of the planets left out.

A typical example of the current approach of those who use asteroids is to be found in J. Lee Lehman's The Ultimate Asteroid Book. For interpretation she relies on names. Now if we consider the outer planets, the name of Pluto is quite appropriate but one can learn little about the astrological Uranus from the mythical one. In the case of Neptune, both god and planet are concerned with the sea, but there is no exact match between them: the god (or at least his Greek counterpart Poseidon) was associated with horses and earthquakes, the planet with mediums and narcotics. To expect that intuition or inspiration has been successful in the naming of over three thousand asteroids is surely naive optimism. The names are at least entertaining though, a popular astronomers' game being to make sentences from them, like 'Rockerfellia Neva Edda McDonalda Hamburga'.

For Lehman the problem of numbers is met with the suggestion that, unlike planets, "not all asteroids properly belong in a reading ... however, if the client is a soprano who is a Verdi freak . . . it might be interesting to find out the position of Aida or at least the nodal position of Aida in her chart". The trouble with this idea is that if we don't know anything about the client, we can't tell which asteroids to use; and if we do, we don't need to use them. And surely if asteroids mean anything, one strongly placed in a chart must mean something. What if Aida is rising in your chart and you are neither a singer nor an opera enthusiast? How can you manifest the asteroid Beer if you were born in Saudi Arabia?

Dr Lehman also holds that "nodal positions have essentially the same properties as the asteroids themselves". This more than doubles the number of factors in the chart. To judge by some of the examples given, when she refers to an asteroid featuring in a chart, this seems to mean when the geocentric or heliocentric position of the asteroid, or one of its nodes, makes some aspect (major or minor) to an angle or to the geocentric or heliocentric position of a planet, without too much attention being paid to which angle or planet is involved. The varying relationship between geocentric and heliocentric longitudes makes it difficult to calculate the exact chance of such a thing happening in any chart, but it is certainly over 95%. By Lehman's criteria, every one of the seven asteroids in the book features in my chart - five of them with the angles or lights. From the list of nodes, I find that my Sun is in partile major aspect to those of Aarhus, Atlantis, Locarno, Suevia, and Yalta, none of which I have ever visited (though I wouldn't mind a week in Atlantis).

The instability of asteroid orbits is completely ignored, yet should we include in a chart an object which is not a permanent member of the solar system? How are we supposed to spot 'wounded healers' if Chiron gets captured by Saturn? The whole approach is very reminiscent of that adopted by those who use hypothetical planets, and about as reliable in my opinion.

The Comets

Since Aristotle believed the heavens to be perfect and unchanging, he considered comets to be atmospheric phenomena like lightning, and his view was accepted by most later astronomers. Some ancient writers did reject it, Senecca arguing that if it were true, the behaviour of comets should be affected by the weather. Aristotle was finally refuted by Tycho Brahe, who worked out the actual orbit of a comet in 1577 and showed it was nearly as far off as Venus. Even then Galileo, in one of his fits of pig-headedness, continued to repeat Aristotle's view.

There are vast numbers of comets in the solar system, more than there are asteroids, but most lie out of sight beyond Pluto. If they are drawn inwards by the planets, they may find new orbits which bring them closer to the Sun. These orbits can be very elongated and their periods vary greatly: three years for Encke's Comet and three million years for the Great Comet of 1864.

Since comets are mostly composed of ices, their outer layer vaporises as they approach the Sun, forming a cloud of gas and dust called the coma, which gives them a fuzzy appearance. Some of the coma is pushed away by solar radiation to form a tail, which consequently always points away from the Sun. Eventually, so much material is lost that the cometary core disintegrates and turns into a swarm of meteors.

Among the most recently discovered comets are the Centaurids, such as Chiron and Pholus. These were first called asteroids, but Chiron has been observed to occasionally develop a coma at its closest approach to the Sun. As will be explained below, Chiron's eccentric orbit cannot be original and the coma confirms that it has not existed for long, or else the outer layers would have been lost by now: the icy outer satellites of Jupiter and Saturn show no comas.

Comets are only used in astrology when they are visible. This is a legacy from Babylonian times, when only observed phenomena counted as omens, but it does not mean that it is not true. Traditionally they are considered to be malefic: Halley's Comet turned up in 1066 for the Battle of Hastings and in 1910 for the deterioration in international relations which culminated in World War I. Sceptics, of course, will naturally point out that such events are always happening!

Considering the attention paid to comets over the millennia, it is surprising how little usable information is available. They are virtually ignored in modern works on mundane astrology, and early authors have little to offer other than obscure classifications by shape and colour, and the suggestion that a comet in a sign affects the countries ruled by it. Comets are obviously an important field for future research.

An interesting case is the passage of Comet Kohoutek through the 1801 chart for the United Kingdom in 1973-4. Faced with industrial action in the coal mining, gas, and electricity industries, the government declared a state of emergency on 13 November, to enable it to take steps to regulate the use of power. On that day the comet was at 8° Libra, transiting the ascendant (the nation) and applying to the square of the Sun (government). On 13 December it was announced that industry would be restricted to a three-day working week, in order to conserve fuel. At that time, Kohoutek was at 24° Scorpio in the 2nd house (the economy) and squaring Saturn in the 11th (state institutions). When this measure came into effect, on Monday 31 December, Kohoutek was at 18° Capricorn, in the 4th house and in opposition to the Moon in the 10th (democratic government). On 28 February 1974 the government lost the election it had called in the hope of a mandate to coerce the Trade Unions. The comet was at 15° Taurus in the 8th house (the death of the government), squaring Venus, lady of the ascendant (national harmony had been disrupted). On 4 March, the government resigned, with the comet at 19° Taurus, squaring the 10th house Moon.

UK: 1801

Coincidence seems a far-fetched explanation for correlations like these. It may be significant that Kohoutek, although not a brilliant comet, was moving close to the ecliptic at the time of these transits, which may have brought it into a closer relationship with the planets.

The Origin of the Asteroids and Comets

Many years ago I owned a children's encyclopaedia which described, with illustrations, two theories of the origin of the solar system. One had both the Sun and the planets condensing out of a cloud of gas. The other had the Sun experiencing a near collision with another star, which drew out of it a long streamer of material which later condensed into the planets. At the time I found the second explanation much more appealing - it certainly made for a better picture! Alas, it wouldn't work: the material pulled out would just disperse into space.

That leaves us with the gas cloud which, as modern computer modelling has demonstrated, would produce the right result. If the cloud were dense enough to start with, it would become denser as the gravitational attraction of the particles became more important than the collisions driving them apart. The particles would also develop a collective motion: as opposing motions would be cancelled out, the cloud would end up rotating. Just as spinning skaters speed up if they pull their arms in, so the cloud speeds up as it contracts, and its outer parts spread and flatten as a result of centrifugal force. Eventually, the pressure and temperature in the centre will set off nuclear fusion, producing a star surrounded by a disk of gas. Such things can actually be seen in the sky today, confirming the theory.

With the passing of time, the gas disk condenses to become a cloud of solid particles. These frequently stick together when striking each other, and the larger the particle so produced, the more it attracts others towards it. More computer simulation shows that the final result of this would be a system of planets in concentric orbits, each rotating on its axis in the same direction as its own orbital motion and the Sun's rotation. The smaller objects would be gradually cleared away: they might collide with the planets, or fall into orbit about them as moons, or be jostled aside by the perturbation of their orbits. Evidence of the collisions is preserved in the craters which cover the inner planets. A really big collision could have the dramatic effect of tilting the planet's axis, and this has happened to all except Mercury and Jupiter: Venus, Uranus, and Pluto have actually been tipped upside down.

One result of the way that the planets formed is a variation in their composition. In warmer regions near the Sun, light materials disperse and the planets from Mercury to Mars are made of rock and metal. Further out, light gases condense in the colder conditions: all the bodies formed contain large amounts of water and hydrocarbons, the bigger ones even able to attract and retain hydrogen.

Not all of the smaller bodies (called planetesimals) are swept up by the planets. Two large groups remain: the asteroid belt, between Mars and Jupiter, and the Kuiper belt, beyond Pluto. The asteroids could never condense into a planet, as they are constantly stirred up by Jupiter, but they are far enough away from Jupiter and Mars not to be pulled out of their orbits. The planetesimals in the Kuiper belt are probably too spread out to coalesce and there is no planet to sweep them away. Because they were formed in two very different areas, the planetesimals in the two belts have different compositions. The asteroids are rocky or metallic, but the Kuiper planetesimals are icy.

Because of their small size and close proximity to each other, planetesimals tend to have unstable orbits: they can be pulled into new orbits by the planets and they may collide, particularly in the asteroid belt. Those in the Kuiper belt are most easily disturbed, as they are so far from the Sun, and they give rise to comets; but members of both groups have ended up in new orbits or have been captured as moons. Any planetesimal in an orbit which crosses that of a planet cannot be in its original position, as all orbits started concentric. Any satellite which goes round its planet backwards or has the wrong composition for its distance from the Sun cannot be original. The planets from Mars to Neptune all have satellites which are recently captured planetesimals. The visible comets reveal their late origin by crossing the planetary orbits and moving too close to the Sun for bodies composed of ice; some (eg., Halley's Comet) also have a retrograde orbit.

Although planets, moons and planetesimals may seem to be very different astronomically, their common origin shows that this is not so. A planet may have more in common with a moon or a planetesimal than with another planet: Mercury and Ceres are both lumps of rock, Saturn and Halley's Comet are both dirty snowballs. Their sizes obviously vary, but these form a continuous series in which the different classes overlap: the Saturnian moon Titan is larger than the planets Mercury and Pluto, and the Martian moon Deimos (a captured asteroid) is the same size as Halley's Comet.

The Meteoroids

The smallest planetesimals are called meteoroids: the traditional names are meteors (for those seen burning up in the sky) and meteorites (for those which hit the ground). The latter, being made of rock or metal, come from the asteroid belt. The meteors are mostly found in swarms, which are the remains of comets that have lost most of their ice and have broken up. It has been recently pointed out by the science journalist John Gribbin that periods of high meteor activity (recorded by Chinese astronomers) have coincided with periods of unrest in Europe: the Hundred Years' War, the Thirty Years' War, and the Napoleonic Wars. Gribbin speculated that the unrest was a psychological effect of the sights, forgetting that the vast majority were tucked up in bed and saw nothing. If their appearance had made a stir in Europe, Gribbin would not have had to rely on Chinese records. It is more likely that the meteor showers may have something of the astrological nature of the comets from which they were formed.


From the appearance of meteors and unusual celestial phenomena in general

The ancient astrologers were accustomed to pay peculiar attention to that part or quarter of heaven in which these celestial appearances were first seen: added to which, they observed in what constellation of heaven, and near what fixed stars of eminence they were posited, in respect to their longitude. They also deduced a system of presages from their colour, shape, resemblance to swords, crowns, halos, wands, flames of fire, &c. But the most philosophical and also natural way, is evidently to cast a theme of heaven, to that hour in which they are first seen, and from which the certain cause of their appearance is more likely to become manifest to the student, than in any other manner.

Raphael, Manual of Astrology, (1828) p.246


© David McCann. First published in The Traditional Astrologer magazine, issue 14; May 1997.

Mundane Astrology