-> Indeed. some claim that by today's standards, Pluto would not qua;ify as a 
-> planet. 
 
->  > So, I don't know if Pluto is a planet or not. 
 
->  > It was a planet when I went to grade school in the 1960's. 
 
->  > A lot has changed since then. 
 
-> One of the things that changed is that objects have been discovered beyond 
-> Neptune's orbit that are not classied as planets. And recently at least two  
-> them have been found that may be larger than Pluto. 
  
When it was originally discovered, Pluto was thought to be similar in 
mass to Neptune and Uranus. Inaccurate measurements of alleged 
perturbations caused by Pluto's gravity led to this conclusion. The 
fact that it looked so small was a bit of a mystery. One theory that 
was around when I was a kid was that Pluto's surface was shiny, so it 
was like a big metal ball. All that could be seen with telescopes was 
the tiny reflection of the sun in this surface. The rest of the planet 
was invisible. 
  
This theory bit the dust when an occultation of a star by Pluto was 
observed. The star's light was *not* blocked by the presumed invisible 
part of Pluto. Pluto really was as small as it looked. At about the 
same time, the error in the mass estimate was discovered. 
  
But the classification of Pluto as a planet, which was partly based on 
its apparent large mass, had become ingrained in astronomical culture. 
*Maybe*, because of the other large Kuiper Belt Objects that have 
recently been discovered, this may change. Personally, I hope that it 
does. 
  
                                   dow 
--- Platinum Xpress/Win/WINServer v3.0pr5