On July 29 the boundaries of our solar system expanded by seven billion miles, as astronomers announced the discovery of a new planet in orbit around our Sun. The latest in a series of planet-like objects found by astronomers Mike Brown, Chad Trujillo and David Rabinowitz, object 2003 UB313 is unique in that it is the first outer solar system object discovered that is bigger than Pluto.(1)

Working from photographs taken with the 48-inch Samuel Oschin telescope at Caltech's Palomar Observatory outside San Diego, the team has discovered several new planetoids. But not since the discovery of Neptune in 1846 has an object this large been found to orbit our Sun.

What Makes a Planet a Planet?

Considering astronomers' hesitance to grant planet status, the enthusiasm attending the announcement of 2003 UB 313 as our solar system's tenth planet comes as something of a surprise. For years astronomers, including Mike Brown, have argued that Pluto itself should not be classified as a planet. While there is no universally accepted definition of planethood, the historical planets—all except for Pluto—share some common distinctions. They are round, they orbit the Sun, and they can be classified as solitary individuals as opposed to members of large populations.

A solitary individual is a planet that exists in a region of space where it is the only one of its kind. Our own planet is a perfect illustration of the solitary individual, says Brown: "The Earth has a diameter of about 12,000 km, while the largest other object in the Earth's vicinity, the asteroid Ganymed, has a diameter of about 41 km."(2)

Members of large populations, by contrast, share their orbital space with other objects like them in size and composition. The asteroid Ceres (900km) is nearly as large as Pluto (932km) and was considered to be the missing fifth planet upon its discovery in 1801. As it turned out, Ceres, though the largest asteroid, is hardly alone in space. She shares the asteroid belt—between Mars and Jupiter—with thousands of similar objects. The largest of these, Pallas and Vesta, are both about half Ceres' size, whereas the difference in size between Earth and Ganymed is a factor of 300.

In the eyes of many astronomers, Pluto's elevation to planet status is an accident of history. When it was found in 1930, Pluto was thought to be the only one of its kind. But astronomers now know it to be a member of a large population in the Kuiper Belt, a region of icy objects with orbits ranging from 30-50 astronomical units, or AU. (An AU is the mean distance between the Earth and Sun.) Some of the more well-known Kuiper Belt Objects, or KBOs, are Quaoar and Varuna, both of which are about half the size of Pluto.

The Consciousness Test

It is axiomatic in astrology that the discovery of a new planet coincides with a need for a new set of psychological/mythological symbols in the collective consciousness to help us explain our experience. As astrologer Jonathan Cainer writes about the discovery of Sedna, "If the earth is ultimately just one living entity, perhaps the entire solar system is also part of that same giant being? In which case, when we discover a new planet at the very edge of our world, it is as if we are discovering a new possibility at the very edge of our own personality!"(3)

By this standard, Pluto definitely passes the consciousness test. Coming just four months after the great stock market crash of October 1929, Pluto's discovery (it was the first planet discovered by an American) heralded the Great Depression and symbolized an age of unparalleled increases in technological power, specifically the power of humans to destroy. For astrologers, the "Lord of the Underworld" represents the cosmic force of regeneration, the divine Will that destroys the old in order to make way for a new, higher order of life. Pluto represents pure transpersonal power, and when its energies are applied unconsciously some very dark things can happen. With Pluto on board, Cainer notes, "From the Great Depression to the Holocaust, from the atomic bomb to the advent of global warming, humanity finally got to see just what a terrifying place it was capable of turning the world into." (Editor's note: see Jeff Jawer's The Discovery of the Outer Planets for more on the discovery of Uranus, Neptune and Pluto.)

The Centaur Chiron, "the wounded healer," is another example of the consciousness test in action. At about 150km in diameter, Chiron is only as large as a medium-sized asteroid. But, with an eccentric orbit that takes it inside of Saturn and outside of Uranus, and with characteristics of an asteroid, a comet and a planet, Chiron was unlike anything the world had seen before. Unable to shoehorn this cosmic shape-shifter into one of the existing categories, scientists needed a whole new class of heavenly body. American Charles Kowal, the astronomer who discovered Chiron, chose to name it after the greatest of the Centaurs, a half-horse, half-human healer who also happened to be the son of Saturn and grandson of Uranus.

Chiron's discovery and associated mythology proved to be a striking bit of synchronicity. Kowal found Chiron in 1977, a time when the world was trying to come to grips with the mechanization, dehumanization and massive destruction of the half-century that followed the discovery of Pluto. We were a nation desperately in need of healing, and Chiron quickly came to symbolize the nascent holistic movement and its emphasis on healing our emotional wounds by expanding awareness to include the whole self. By connecting Saturn (our large social institutions or power structures) and Uranus (the revolutionary spark that leads us to seek freedom and autonomy), Chiron served as a connecting bridge between our animal nature and our spiritual nature and embodied the New Age imperative to re-spirit our social structures.

Will 2003 UB313 pass the consciousness test? Judging by the splash it made upon arrival, one would guess so. Mike Brown discusses his belief that the new object is indeed a planet, and how his evolving thinking has led him to not only change his mind about Pluto but also propose that new objects larger than Pluto be considered planets as well: