Clarification of Answer by
22 May 2006 13:30 PDT
Read the links I gave you, specifically the section titled,
'Is this object really a planet? Is Pluto a planet? What makes a planet?'
and 'How will the planetary status be decided?', on this page:
They answer your question as well as it can be answered. In short:
Scientists have come to realize that, scientifically, Pluto is
different from other planets, but culturally, it's long been
acknowledged as a planet. To resolve this, scientists have (by
a thin margin) voted to define a planet as the current planets
plus celestial objects like Pluto and anything bigger. That's
the current official stance. Here's the quote from the page:
- A special committee of the International Astronomical Union
(IAU) was charged with determining "what is a planet."
- Sometime around the end of 2005, this committee voted by a
narrow margin for the "pluto and everything bigger" definition,
or something close to it.
- The exectutive committee of the IAU then decided to ask the
Division of Planetary Sciences (DPS) of the American Astronomical
Society to make a reccomendation.
- The DPS asked their committee to look in to it.
- The DPS committee decided to form a special committee.
- Rumor has emerged that when the IAU general assembly meets in
August in Prauge they will make a decision on how to make a
Sedna is bigger than Pluto, so, by the current definition, it
is a tenth planet. This doesn't mean that a committee of scientists
can't eventually change their minds, and how they choose to define
a planet. They may eventually decide to reject their current
definition and rule that Pluto and similar objects are not planets
and let the cultural chips fall where they may. Or they may evade
the decision process and hope it all goes away. If they decide
to maintain the current definition, then they'll form another
committee to name the tenth planet officially.
But for now, Sedna is a planet with unofficial pet names.