On Mon, 17 May 2004 19:15:22 GMT, in sci.astro you wrote:

"Erland Gadde" wrote in message
. com...

But, as I understand it today, it was a coincidence that Pluto was
discovered near the predicted position, for Pluto is too small to
cause the disturbances of Neptune's orbit (as is Sedna).

Correct... Pluto was discovered photographically... not via mathematical
prediction.


But were not the places they were looking for Pluto determined
mathematically? This was how Neptune was discovered. They pointed
their telscopes at certain locations which were determined
mathematically. Later when they realized that Neptune was not massive
enough to account for all the deviation in Uranus's position they went
back and looked for another planet.

Until the discovery of Chiron, the mass of Pluto was unknown.

As for Pluto loosing its classification as a planet, this will
probably never happen. What will most likely happen is that Pluto
will be placed at the bottom end of the scale for determining if an
object is a planet or just a very large rock/iceball.