Hi Misty and Danielle,

Well, I didn't do any of that personally, but I admit I mostly agree with the decision that the International Astronomy Union (IAU) made. They did not kick Pluto out of the solar system. They just decided that it was a part of the solar system that they decided to call a "dwarf planet". Pluto is there just like it was before.

Basically, the decision was made because astronomers are now finding lots of small objects like Pluto (which is significantly smaller than other regular planets) in the outer solar system. It was felt (although not everyone agreed) that these smaller object should be grouped together as something separate from the major planets.

It is similar to the situation with the asteroids in the asteroid belt. When the largest ones were first found in the early 1800s people called them planets. Eventually, though, people found that there are a whole _lot_ of asteroids and that they are much smaller than what we usually call planets, so people decided to just call them asteroids.

Xena (which has been renamed "Eris") was discovered by looking at images of the sky taken with very powerful telescopes. Something that is moving inside the solar system will appear to move against the background of even more distant stars.
The person who discovered Eris has a web page showing this:
http://www.gps.caltech.edu/~mbrown/planetlila/

This is how Pluto was found too.

cheers,
Terry