Astrologers and Kuiper belt objects
Posted by c. wagner on November 18, 2009
Astrology is a “discipline” notoriously immune to change. So, what are astronomers to do as more and more good-sized objects, some of them bigger than that formerly-known-as-a-planet … thingie, Pluto, are discovered at the fringes of the solar system?
The article ends with Vanity Fair astrologer Michael Lutin saying that he will consider the newcomers, but remains skeptical of their influence on our daily affairs due to their location at the outer reaches of the solar system: “UB313 is never going to tell you whether Wednesday is good for romance.” [page 149]
Astronomer Neil deGrasse Tyson declares the discussion over Kuiper belt objects moot, saying
Actually, neither will anything else in the sky, unless it’s an asteroid headed toward Earth, scheduled to hit on Wednesday. [page 149]
That is one forecast I wouldn’t like to find in the newspaper. Sheesh.
(Quotes from The Pluto Files.)
slumber-powered 
Laurel Kornfeld said
Pluto is a planet, and so is Eris (UB313), which is the only known Kuiper Belt Object larger than Pluto. Pluto did not stop being a planet because 424 astronomers made a controversial decision and adopted a vague, unusable planet definition. The requirement that an object “clear its orbit” was concocted specifically to exclude Pluto and keep the number of planets in our solar system low. The IAU definition makes no sense in stating that dwarf planets are not planets at all, a departure from the use of the term “dwarf” in astronomy, where dwarf stars are still stars, and dwarf galaxies are still galaxies. Also, the IAU definition classifies objects solely by where they are while ignoring what they are. If Earth were in Pluto’s orbit, according to this definition, it would not be a planet either. A definition that takes the same object and makes it a planet in one location and not a planet in another location is essentially useless.
d.d. mayhem said
This is true. If memory serves, Ceres, the largest object in the asteroid belt, is also considered a dwarf planet.
None of which changes Tyson’s main point in the quote, which is that astrology doesn’t work, whether you include Pluto, Eris, and Ceres or not.
Kevin Heider said
The requirement that a planet “clear its orbit” is no worse than the requirement that a planet “orbit the Sun”. The definition of a planet has had a “where-it-is” clause since shortly after Galileo pointed his telescope at Jupiter and discovered the 4 Galilean moons. Unless society is ready to call the Earth-Moon system a “double planet” based on “what the objects are” and not where-the-objects are, there is no *need* for Pluto and his cousins to be included with the dominant bodies in the solar system.
Alan Boyle said
I really think the planet-vs.-moon problem is a non-problem. Moons, as in satellites, are pretty well-defined. They’re objects that orbit another object. In fact, you could conceivably define a planet as a star’s satellite. Aha, you say, but you’re including asteroids and comets. Well, sure, they’re already considered minor planets. Probably the most acceptable way to break the categories down is the way that the IAU did: minor planets (small solar system bodies that are not round), dwarf planets (little round things) and dominant planets (bigger round things). In our own solar system, it’s rather obvious which are the dominant planets, but we already know that the “clearing out the orbit” idea doesn’t work in other solar systems (for example, large resonant planets such as HD 82943 b and c). I think the “orbit the sun” requirement doesn’t work, either, because that ties you up when it comes to the issue of rogue or free-floating planets. We shouldn’t get too doctrinaire about such a common term. Now, on the original topic, I definitely agree that adding Eris or Makemake or 1992 QB1 will make no difference in the efficacy of astrology. But we should figure out what to do about that asteroid, whether it comes on Wednesday, in 2012, 2036 or 4028.
Kevin Heider said
True, some exo-planets are is resonance, but a lot of exo-planet simulations also seem to show that like the Solar System, most of these systems are full. This means that there is not room to drop in another large body without making the system unstable. I do not think the IAU’s definition is perfect. But I do think having 3 classes of objects “planets, dwarfs, and asteroids (belt objects)” is not a bad way to go at this time. I don’t think the IAU should bother with the definition until 2018, when we have had a few years to digest Dawn & New Horizons, not to mention any other new knowledge on the solar system and exo-systems. Certainly the general public does not care that we have over 225,000 “belt objects” with known orbits. Large dwarf planet candidate 2007 OR10 (nickname: Snow White) was just recently assigned as Minor Planet #225088.