Pluto is the ninth planet from the sun, but not so long
ago, it was the eighth planet. About every 220 years, Pluto switches places
with Neptune, becoming the 8th planet. This happened from
February 7, 1979 through February 11, 1999 when Pluto took over Neptunes
orbit. The reason this happened was that Plutos orbit was stretched out
and tilted causing it to cross with Neptunes orbit. Cylde W. Tombaugh
made the discovery of the planet Pluto on February 18, 1930.
Cylde Tombaugh was able to make this discovery by taking
pictures of the solar system at different times (about one and two weeks
apart). The idea was that Clyde Tombaugh could compare the pictures and try
to notice any differences. The result of this experiment was the discovery
of Pluto. Pluto being so small made it difficult to find. It has one moon
(also known has a satellite) called Charon. In fact, Pluto is so small it
can fit inside the United States.
Occasionally Pluto will cross in front of a reasonably
bright star, making the planet more visible. The last bright star to cross
in front of Pluto occurred in June 1988 and provided the first direct
evidence of Pluto's atmosphere.
If you were to stand on the planet Pluto it would be hard
to see because it is so dark. The only light you might see is the sun, but
it would look more like a very small bright star. From Earth scientists say
that Pluto is a big floating snowball.