Pluto is part of a
family of small, icy worlds that orbits the sun out on the edge of the solar
system. It was once considered the ninth planet in our solar system; however,
since 2006 it is now considered a dwarf planet. Pluto’s orbit is highly
inclined and so elliptical that it actually comes closer to the Sun than
Neptune at times. Its diameter is only 65% of the Earth’s moon though it is
very difficult to observe from Earth. Since it orbits so far from the Sun,
Pluto is cold enough to freeze most compounds. Observations have found evidence
of nitrogen ice, and its atmosphere is thin and composed of Nitrogen (N2),
carbon monoxide (CO) and small amounts of methane (CH4). This thin
atmosphere is said to only be present at times when it is closer to the Sun,
though when it gets further from the Sun the atmosphere is said to freeze and
basically disappear. Pluto’s low gravity (one-twentieth of the Earth’s gravity)
causes the thin atmosphere to extend much further in altitude than the Earth’s
atmosphere. Although Pluto is a small planetary body, it has five moons:
Charon, Nix, Hydra, Kerberos and Styx.1
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| Figure 1 - Pluto (http://onwardstate.com/wp-content/uploads/2014/03/pluto.jpg) |
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| Figure 2 - Pluto and its Moons (http://theplanets.org/wp-content/uploads/2014/09/pluto-moons.jpg) |
Pluto was first discovered in 1930 by
Clyde Tombaugh at the Lowell observatory, based on predictions from other
astronomers. Clyde Tombaugh was born in Illinois on February 4, 1906. Tombaugh
built over 30 telescopes in his lifetime since building his first telescope at
the age of twenty. Using his telescopes, Tombaugh made detailed observations of
Jupiter and Mars and sent them to the Lowell Observatory in hope of
recognition. As a result, in 1928, he was offered a job at the Lowell
Observatory in Arizona. Scientists observed weird movements by Uranus that
could be attributed to another planetary body that was not Neptune, this was
the reason scientists were searching for a ninth planet to possibly explain
such movements. In 1930, just a couple years after he was offered a job,
Tombaugh noticed movement across two images taken of the same area. After
studying this object to verify the movement, Tombaugh was able to announce it
as the discovery of a ninth planet. The name Pluto was suggested by an
eleven-year old girl and was named after the Greek god of the underworld. 2
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| Figure 3 - Clyde Tombaugh (http://i.space.com/images/i/000/020/845/i02/clyde-tombaugh-telescope.jpg?1345732608) |
Plutinos are objects
from the Kupier Belt which have a 3:2 orbital resonance with Neptune and have
semi-major axes of ~39 AU. Some of the Plutinos also cross Neptune in their
orbit (like Pluto). The name Plutino is named after Pluto because of the
orbital resonance similarities and it does not imply similarities between
physical characteristics. The first plutino, besides Pluto itself, was
discovered in 1993 and is named (385185) 1993 RO.
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good basic information but you need to go into a lot more detail
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