Pluto gets the booto! After 76 years in the big leagues, Pluto gets a demotion.

"My Very Educated Mother Just Showed Us Nine Planets." For decades, that sentence helped kids remember the names of the planets in our solar system. [The first letter of each word is the first letter of each planet, in order, from the one closest to the sun outward.] Now, we need to come up with a new reminder--minus the P.

On August 24, members of the International Astronomical Union (IAU) voted Pluto out of the planet family. Pluto had to go, the astronomers said, because it didn't fit their new definition of what a planet is.

When Pluto was first spotted, in t930, people thought it was bigger than it is. Compared to the eight "classical" planets, Pluto is actually tiny. lit is smaller than Earth's moon.) Newer, more powerful telescopes have since revealed other objects in our solar system that are bigger than Pluto. If Pluto is a planet, why not the others?

Another difference between Pluto and the others is its orbit. Unlike the first eight, Pluto's orbit is lopsided, and crosses nearby Neptune's path at times.

But astronomers didn't abandon Pluto altogether. The IAU came up with a category for all the smaller "planetlike" bodies in the solar system. Pluto belongs to a new family now, known as dwarf planets. But don't feel too sorry for Pluto: It has several other space objects to keep it company.

Web Watch: An interview with the director of the Hayden Planetarium teacher.scholastic.com/scholasticnews/ indepth/space.