PRAGUE, Czech Republic Leading astronomers declared Thursday that Pluto is no longer a planet under historic new guidelines that downsize the solar system from nine planets to eight.Its a sad day. No longer can "My Very Excellent Mother Just Send Us Nine Pies." And while I am sure that this comes as no surprise for Gustav Holst, it is shocking to me.
After a tumultuous week of clashing over the essence of the cosmos, the International Astronomical Union stripped Pluto of the planetary status it has held since its discovery in 1930.
The new definition of what is -- and isn't -- a planet fills a centuries-old black hole for scientists who have labored since Copernicus without one.
Under the new definitions, a "Planet" is defined as:
"a celestial body that is in orbit around the sun, has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a nearly round shape, and has cleared the neighborhood around its orbit."
Pluto is automatically disqualified because its oblong orbit overlaps with Neptune's. Instead, it will be reclassified in a new category of "dwarf planets," similar to what long have been termed "minor planets."
The definition also lays out a third class of lesser objects that orbit the sun --- "small solar system bodies," a term that will apply to numerous asteroids, comets and other natural satellites.
As our scientific knowledge base increases, many things that we once believed to be one thing may turn out to be something completely different. Look, we now know that the planets revolve around the sun, not the other way around. Obviously our understanding of the vastness of the universe is only in its infancy. Many more objects are yet to be discovered, and other solar systems yet to be explored. Pluto may turn out to be more of the norm rather than the exception.