Tiny Pluto

Fact File:

Diameter: 2500 km

Distance to Sun: 39 AU

Solar Orbit: 248 years

No of Moons: 3

Astronomers are normally quite tranquil people, however fierce rows have been erupting in recent years over whether Pluto is still 'really' a planet, or merely the largest member of the Kuyper belt. The latter is a huge belt of rocks and debris out beyoAstronomers are normally quite tranquil people, however fierce rows have been erupting in recent years over whether Pluto is still 'really' a planet, or merely the largest member of the Kuyper belt. The latter is a huge belt of rocks and debris out beyond Neptune. But Pluto's days of planethood were numbered, and astronomers in 2006 demoted it to a 'dwarf planet' - whatever that is.s in 2006 demoted it to a 'dwarf planet' - whatever that i

In mythology, Pluto was the underworld ruler of Hades who could wear a helmet of invisibility. At the position given in the ephemeris for Pluto, there is, literally, empty space. Pluto has an extra-large moon, called Charon (the Ferryman, who carried people across the Styx in mythology), and the two of them both orbit around an empty centre- point. Emptiness is present at the joint centre of gravity of Pluto and its moon, around which they both travel, ever facing it. 

Perceval Lowell was the US astronomer who predicted where Pluto was going to be.  He spent years scribbling out calculations, concerning Pluto's gravity pull on Neptune, and had the Flagstaff Observatory in Arizona built so he could spend years searching for it, and eventually died disheartened. (1) After his death, a young man Clyde Tombaugh was employed by the observatory to continue the search, and found it, just where Lowell had predicted it would be.


At four o'clock in the afternoon, the 24-year old Clyde Tombaugh was routinely checking over photographs of star-fields, when he became convinced that he had solved the great quest: 'I was walking on the ceiling. I was now 100% sure', he recorded. 'For the next forty-five minutes or so, I was in the most excited state of mind in my life.' (2) Later that same day, Clyde's father told his mother while she was hanging out the washing, 'Clyde's discovered a planet!' Two days later it was first viewed with a human eye, and then on March 13th, Lowell's birthday, the discovery was publicly announced. Journalists swarmed up Mars Hill to the observatory.

Thereby Perceval Lowell was the only mortal to get his initials onto a planetary glyph, as PL. Neptune's discovery had been a powerful vindication of the law of gravity, having its position exactly predicted thereby, and Pluto's discovery was hailed in similar terms: 'The Orbit, now that we know it, is found to be so similar to that which Lowell predicted from his calculations fifteen years ago, that it is quite incredible that the agreement can be due to accident,' intoned the Scientific American, in December 1930. Lowell's predicted orbit was within five degrees of zodiac longitude, and three degrees for perihelion position! Also, he had predicted a steep inclination of the orbit to the ecliptic, though not quite as steep as was actually found.

Subsequent events showed the prediction was rather a celestial mockery of this rigorous deductive process. Indeed, it invites some comparison with Lowell's earlier quest for Martian canals. Percival Lowell, who set up the observatory that discovered Pluto, had earlier become famous for his espousal of the canals on Mars he claimed to have seen, and which he described in detail as showing intelligent and pacific life there.  His reputation collapsed as these evaporated, and his quest for Pluto was an attempt to restore his shattered reputation.  Eventually, all his detailed predictions of Pluto's position turned out to be just as baseless as his Mars canals - the single difference being, that in the latter case, he happened to be right.


An American astronomer Russell concluded:


The question arises ... why is there an

 actual planet moving in an orbit

 which is so uncannily like the one predicted?...

 There seems no escape from the conclusion that

 this is a matter of chance. That so close a set

 of chance coincidences should occur is almost

 incredible, but the evidence employed

by Brown permits of no other conclusion (3)



Instead of demonstrating the rigorous power of deductive logic, its discovery was rather demonstrating after all the concept of synchronicity. Pluto crossed the ecliptic in September of 1930, that being the only period in which the Flagstaff Observatory's quest could have been successful. With its steep inclination to the ecliptic at 17°, much more than any other planet, Pluto only stays close to it for a comparatively short period. It was in the one part of its orbit when it was amenable to being discovered by the methods then used, being discovered at its node.


Estimates of Pluto's size kept shrinking throughout the 1970s, so that the prospect of its total disappearance became a standing joke amongst astronomers. The circumstances of its discovery from the perturbation of the orbit of Neptune had to be dismissed as a mere computation error.  Its mass was far too small to have caused any such disturbance.  It was on the verge of being dismissed as a mere lost moon of Neptune, when in 1978, as it entered the orbit of Neptune, it appeared with a suspiciously large moon, one half of its own diameter. 

Pluto's Moon Charon

Charon of the River Styx

Astrologers very soon acquired their image of what was 'Plutonic,' of how they perceived Pluto's influence, because the world seemed to change so drastically following its appearance. The atom was split, fascism grew in Europe, jazz and psychoanalysis became popular, a new era of invisible astronomy began using infra-red telescopes, antimatter was detected (1932), and the first vampire movies appeared (4).


The 1980s began with Pluto coming closer and actually entering into the orbit of Neptune, and it remained closer to us than Neptune for the next twenty years. This seemed enormously stressful, with a majority of the population expecting nuclear war (in the UK), as missiles tipped with 'Pluto's element' plutonium were wheeled around the countryside. Such missiles should remain underground and out of sight. When in 1989 Pluto reached its perihelion, all that tension dissolved. The Berlin Wall came down and the Cold War was soon a mere memory. Pluto has a highly elliptical orbit, making this nearest-approach quite a marked event.

Clyde Tombaugh (left) was a maverick astronomer. He claimed to have seen UFOs and testified to this effect, which no astronomer would normally do. They could, he suggested, be coming from Mars. From his home in New Mexico, he saw in August 1949 some bluish-green objects in the sky, which were, he said, the strangest things he ever saw. He was even named as being head of some secret UFO project, and wrote to a friend that he had seen several UFO-type phenomena (5). Once, in the dead of night, when strolling home from his observatory, he noticed what he took to be a large dog walking beside him, and then realised that it was no dog, but a prairie wolf (6). These are, perhaps, somewhat 'Plutonic' situations, which most of us would never experience.



(1) - Lowell's natal Moon at 17°43' Capricorn, conjunct his MC, was opposite to Pluto's position at its discovery (17°46' Cancer) within minutes of arc1 (13 Mar 1855, 7.45 LMT 42N21 71W4, source: Mark Edmund Jones.

(2) - David Levy, Clyde Tombaugh, Discoveror of the planet Pluto AZ 1991 p.5

(3) - http://Neptune_and_Pluto.html

(4) - 'Dracula', 1931 and 'Vampyr', 1932. The first zombie film was 'White Zombie', 1932. Also, the horror film classic, 'Frankenstein' appeared in 1931.

(5) - M.D.Swords, 'Clyde Tombaugh, Mars & UFOs' Journal of Scientific Exploration, 1999, 13, 68-94: https://www.scientificexploration.org/docs/13/jse_13_4_swords.pdf

(6) - Patrick Moore, The Sky at Night, 1985 PSL, p.91

Additional related Pluto articles:-

Pluto R.I.P