Since its discovery in 1930 by astronomer Clyde Tombaugh, modern astrologers have generally come to the consensus that it is the ruler (or co-ruler) of the sign Scorpio. With the most eccentric orbit of any major body in our solar system, Pluto is usually the ninth planet out from the sun. However, during its 248 year orbit, there is a twenty-year period when its orbit takes it inside the orbit of Neptune. The last time this happened was from 1979 to 1999.|
Astronomers had long concluded that any new planets should receive a name from the pantheon of Greek deities, and the name Pluto was among those commonly being held in reserve for such a discovery. The final naming honors reportedly go to an eleven-year-old British girl named Venetia Burney, who referred to a Disney cartoon character (Goofy's dog) in a letter recommending that Pluto be chosen as the name for the newly discovered planet.
Unique hardly begins to describe Pluto's peculiarities. At Pluto's closest approach to the sun (perihelion) it is 2.7 billion miles from it (or 4.34 billion kilometers, or 29.7 AU or astronomical units). When it is farthest away from the sun (aphelion), it is 4.6 billion miles away from the sun (or 7.4 billion kilometers, or 29.5 AU). Another way to appreciate the vast distances involved is that, if it takes just over eight minutes for light to reach earth from the sun, it takes sunlight approximately 5½ hours to reach Pluto.
Pluto's orbit, in contrast to that of the other planets, is quite oval-shaped and it is "tilted" 17.1 degrees from the ecliptic (the "normal" orbital plane). Also, from our perspective, the planet spins lying over on its side (its rotational axis is tilted 122 degrees). While the earth's North Pole is 23.5 degrees above its orbital plane, Pluto's is 32 degrees below.
From the surface of Pluto, an observer would see the Sun rising in the West and setting in the East. Pluto is also the coldest planet in the solar system.
Since Pluto's orbit crosses that of Neptune, it seems reasonable to ask whether the two planets will ever collide. Astronomers have concluded that the two planets are in a resonance state, an effect of their periodic gravitational influence on each other, with the result that Pluto's orbital period is exactly 1.5 longer than Neptune's, and the two can consequently never collide.
There is a longstanding controversy among astronomers over whether Pluto is a planet at all, since its mass is less than that of seven of the moons of other, larger planets (Callisto, Europa, Ganymede, Io, Moon, Titan and Triton). It is 2/3rds the diameter of the earth's Moon, and is about 1/455th (0.2%) of the earth's mass.
Pluto's own moon, Charon, which was discovered in 1978 by Jim Christy, has characteristics that make it appear that Pluto and its moon were at one time a single object, separated by a collision with another object. The orbital characteristics of the two are such that each keeps the same side facing the other, and they have the highest angular momentum of any two bodies in the Solar System - almost at the stability threshold for each. Charon is of extremely low density, and is probably an icy moon similar to those circling Saturn. Pluto on the other hand, is believed to be of a rocky consistency but is less dense than Mars, and it has a (very) thin atmosphere composed mostly of methane.
||2,301 km (1,430 miles)|
|Length of Day
||6 Earth days 9 hrs|
||0.002 x Earth|
|Length of year
||248 Earth years|
||Approx. 2 (water=1)|
|Tilt of Axis
|Minimum Distance from Sun
||4.34 billion km (2.7 billion miles)|
||0.03 x Earth|
|Maximum Distance from Sun
||7.4 billion km (4.6 billion miles)|
||-229 degrees C (-380 degrees F)|
|Minimum Distance from Earth
||4.34 billion km (2.7 billion miles)|
||1 known (Charon)|
|Pluto Solar System Data
|Orbit's Radius (MMKm)
|Orbit's Radius (A.U.)
|Synodic Period (days)
|Sidereal Period (days)
|Diameter / D. Earth
|Mass / M. Earth
|Gravity / G. Earth
|Escape V. (Km/seg.)
|Axial Tilt (°)
Copyright: Matrix Software
Bio: Clarke Fountain
Clarke Fountain has been studying astrology with varying levels of intensity since the 1960s, is a U.S. Navy veteran, and gave his first professional reading in 1977 in San Francisco. After years of doing every kind of job under the sun, he earned an M.A. in Buddhist Studies from the Naropa Institute (as it was then called) in 1989 and at that time became involved with aspects of publishing. Astrology has been one of the few consistent threads in his otherwise extremely varied life, and he is delighted to have the opportunity to serve the astrological community as the Editor for “Astro Talk Online Astrological Magazine.”