All About Pluto
Date: 1999 - 2000
What is known about pluto? I am 13 years old and interested in pluto.
Pluto is this really goofy dog that Walt Disney invented.
Actually, I'm no expert on Pluto.
Here is some info, mostly from the McGraw-Hill Encyclopedia of
Science and Technology: Pluto's radius is approx. 715 mi (1150 km), so it is
smaller than our moon (whose radius is 1080 mi, or 1738 km); its moon Charon has
a radius of approx. 368 mi (593 km), so Pluto-Charon is the closest thing we have in our solar system to
a double planet. The surface temperature is believed to be about 50 degrees K,
or -370 degrees F. Though it is usually the 9th planet in terms of distance from
the Sun, Pluto has actually been closer to the Sun than Neptune since sometime in 1989 and will
continue this until sometime in 1999. This is because of its eccentric orbit:
its minimum and maximum distances from the Sun are approx. 2.76 billion miles
and 4.55 billion miles (4.43 billion km and 7.32 billion km) respectively. One Pluto "day" equals
6.4 Earth days and a Pluto "year" equals about 248 Earth years. According to the
January issue of Sky and Telescope, Pluto's mass is about 1.3 x 10^25 gr. or
roughly 1/5 that of our moon, and Charon's mass is about 1/12 of Pluto's mass. This implies that
Pluto's average density is around 2 gr/cc, which suggests that it is made up of
about equal parts of ice and rock; Charon, on the other hand, has an average
density of only 1.2 - 1.3 gr/cc, which suggests that it is mostly ice. If true, this makes it very
unlikely that Pluto and Charon formed together.
There's a lot more info out
there, in encyclopedias
and astronomy books. Don't be satisfied with the little bit written here!
Try this link: http://en.wikipedia.org/wiki/Pluto
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Update: June 2012