Download Pluto - knoMi

By Gabby Tarantino
What is a planet? We've been asking that question
at least since Greek astronomers came up with the
word to describe the bright points of light that
seemed to wander among fixed stars. Our solar
system's planet count has soared as high as 15
before it was decided that some discoveries were
different and should be called asteroids.
Because Pluto and Charon are so small and
far away, they are extremely difficult to
observe from Earth. In the late 1980s, Pluto
and Charon passed in front of each other
repeatedly for several years. Observations
of these rare events allowed astronomers
to make rudimentary maps of each body
showing areas of relative brightness and
darkness.
Pluto has a very large moon that is almost
half its size named Charon, which was
discovered in 1978. This moon is so big
that Pluto and Charon are sometimes
referred to as a double dwarf planet
system. The distance between them is
19,640 km (12,200 miles).
Pluto is the only world named by an 11year-old girl. In 1930, Venetia Burney of
Oxford, England, suggested to her
grandfather that the new discovery be
named for the Roman god the underworld.
He forwarded the name to the Lowell
Observatory and it was selected. Pluto's
moons are named for other mythological
figures associated with the underworld.
Charon is named for the river Styx
boatman who ferries souls in the
underworld; Nix is named for the mother
of Charon, who is also the goddess of
darkness and night and Hydra is named
for the nine-headed serpent that guards
the underworld
Pluto, which was discovered in 1930, is
but a dot of light in even the largest Earthbased telescopes. Pluto is 2/3 the size of
Earth's moon but 1,200 times farther away,
which makes viewing surface detail as
difficult as trying to read the printing on a
golf ball located thirty-three miles away
The adjacent movie made from recent
Hubble Space Telescope computer
enhanced images indicates that we are
finally beginning to resolve some detail on
the surface of this distant planet
This, and other peculiar aspects of Pluto's
orbit, have led to some speculation that
Pluto is not really a planet but instead an
escaped moon of one of the gas giant
planets, most likely Neptune. Its
composition, as inferred from its density
of 2.1 g/cc, is largely ices. Thus, Pluto is
more similar in structure to moons of the
gas giant planets than it is to the
terrestrial planets. However, other details
may favor an origin of Pluto independent
of Neptune, so this is an open question at
present
Pluto is about 1,413 miles (2274 km) in
diameter. This is about 1/5 the diameter of
the Earth.
Pluto is smaller than the 8 planets in our
Solar System.
Pluto is 39 times farther from than the sun
than the Earth is. Pluto ranges from 2.8 to
4.6 billion miles (4.447 billion to 7.38 billion
km) from the Sun. From Pluto, the sun
would look like a tiny dot in the sky.
Not much is known about Pluto's
atmosphere. It is probably mostly nitrogen
with a little carbon monoxide and methane
- definitely not breatheable by humans.
The atmospheric pressure is probably very
low. The atmosphere forms when Pluto is
closest to the Sun and the frozen methane
is vaporized by the solar heat. When it is
farther from the Sun, the methane freezes
again. From Pluto, the sky would appear
black, even when the Sun (the size of a
star) is up.
Even though Pluto is a dwarf planet, and
no longer officially a planet, it’ll still be a
fascinating target for study. And that’s
why NASA has sent their New Horizons
spacecraft off to visit it. New Horizons will
reach Pluto in July 2015, and capture the
first close-up images of the (dwarf)
planet’s
After a year of observations, Tombaugh
finally discovered an object in the right
orbit, and declared that he had discovered
Planet X. Because they had discovered it,
the Lowell team were allowed to name it.
They settled on Pluto, a name suggested by
an 11-year old school girl in Oxford,
England (no, it wasn’t named after the
Disney character, but the Roman god of
the underworld)