Pluto
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- Pluto is the 9th planet from the Sun.
- The planet Pluto has a diameter of 1500 miles.
- At a distance of 3.67 billion miles,
it takes 248 years to circle the Sun.
- One day lasts 6 days, 7 hours of Earth time.
Pluto obstructed by its moon, Charon (lower
right). DRAWING / NASA |
Facts about Pluto
A. Pluto, named after the Roman god of the underworld, is not a Jovian Planet. American astronomer Clyde Tombaugh
discovered the planet in 1930. Pluto's large moon is named after Charon, the ferryman over Styx, the river of the
dead. Charon is very large compared to Pluto, and in fact it could be said that Pluto and Charon orbit one another,
rather than Charon orbiting Pluto. Charon was not discovered until 1977.
B. Not much is known about Pluto because of its small size and vast distance from the sun. It is presumed to
be made of mostly frozen gasses and water, similar to most comets, and is thus probably a remnant left over from
the formation of the solar system. In addition, because Pluto is very cold, the water on it would have a consistency
similar to that of steel on Earth.
C. Pluto has a very elliptical orbit, which is inclined to the plane of orbit of the other planets by approximately
17 degrees. This trajectory takes it well away from the path of the other planets. Because of its highly elliptical
orbit, Pluto is occasionally closer to the sun than Neptune.
Earn The Astronomical League's Award for Observing the Solar System
Planetary
Club Rules and Regulations
Comparative Data on the Jovian Planets and Pluto
Quantity |
Jupiter
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Saturn
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Uranus
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Neptune
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Pluto
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Equatorial diameter (Km) |
142796
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120000
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50800
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48600
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3300-2800(?)
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Density (kg/cm(3)) |
1330
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706
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1270
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1700
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2000?
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Mass (Earth=1) |
1318.7
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743.6
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14.6
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17.2
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0.0025?
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Surface gravity (Earth=1) |
2.643
|
1.159
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1.11
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1.21
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?
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Escape velocity (km/s) |
60.22
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32.26
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22.5
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23.9
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?
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Mean distance from sun (AU) |
5.2028039
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9.5388437
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19.181843
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30.057984
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39.4
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Mean distance from sun (miles) |
4.836x10(8)
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8.8722x10(8)
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1.7837x10(8)
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2.7946x10(8)
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3.6642x10(8)
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Mean distance from sun (10(6)Km) |
778.3
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1427
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2869
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4497.1
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5900
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Orbital period (Earth years) |
11.867
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29,461
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84,013
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164,793
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247.7
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Orbital period (Earth days) |
4334.3
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10,760
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30,685
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60,189
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90,465
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Orbital velocity (Km/sec) |
13.06
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9.64
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6.81
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5.43
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4.74
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Ave. Surface Temperature (K) |
125
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95
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60
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60
|
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Discovery of Pluto
Reaches 75th Anniversary on February 3, 2005
Flagstaff, AZ - The planet Pluto turns 75 on February 3, 2005. Clyde Tombaugh
discovered the ninth planet in the solar system on the afternoon of
February 18, 1930 while he meticulously examined a pair of deep sky
photographs at Lowell Observatory. Tombaugh exposed the photographs on
two nights in late January using the Observatory's 13-inch Abbott
Lawrence Lowell Telescope. Then, as part of the carefully planned and
executed planet search, Tombaugh "blinked" the two exposures using a
machine called a comparator, looking for motion of objects captured on
film.
"One need only visit Lowell Observatory and view copies of the
discovery images through the same eyepiece used by Clyde Tombaugh to appreciate
what a remarkable discovery this was," said Bob Millis, Director. "The
images are extremely faint and testify to the skill, concentration, and
dedication that Clyde Tombaugh brought to his work."
Lowell Observatory's search for a ninth planet was begun by founder
Percival Lowell in 1905. While Dr. Lowell did not live to see the
discovery of Pluto, the Observatory made the official announcement of
the discovery on Percival Lowell's birth date, March 13, 1930. After
many suggestions, Pluto was selected as the name for the new planet. As
an added plus, the astronomical community adopted a symbol for the
planet that also was a combination of Percival Lowell's initials.
Eleven-year-old Venetia Burney from Oxford, England suggested the name.
Several Lowell Observatory astronomers continue to study Pluto,
including Marc Buie and Will Grundy. Marc Buie has studied the cold,
dark outer regions of the solar system - with a special interest in
Pluto - since the early 1980s. Buie is conducting a long-term project to
monitor Pluto's brightness changes on decade, or longer, time scales.
One of his recent, ongoing projects is aimed at producing a new
generation of Pluto maps based on images taken with the Hubble Space
Telescope. Buie has developed a small, high-performance computing
cluster for this project at the Observatory.
Will Grundy, Lowell Associate Astronomer, studies icy surfaces of outer
solar system objects including Pluto, the icy satellites of giant
planets, centaurs, and Kuiper Belt Objects. Grundy is a science team
member on NASA's New Horizons: A Pluto-Kuiper Belt Mission.
"In the past decade, we have progressed from thinking of Pluto as a
barely resolved 14th magnitude point of light to seeing it as a unique
world with complicated seasonal cycles and with surface regions
exhibiting diverse appearances and chemical compositions," Grundy said.
To complement the astronomy research that includes these ongoing Pluto
studies, Lowell Observatory maintains an active educational and
outreach program. The Observatory will present a Pluto 75th anniversary program
on the evening of Friday, February 18 as part of its regular evening
programs. The nighttime program consists of a special Cosmic Cart at
7:45 p.m., a series of demonstrations particularly suitable for
children. This will be followed by a lecture about Pluto at 8:30 p.m.
The Observatory opens at 7:30 p.m. and telescope viewing will occur
throughout the evening, weather permitting. For more information, visit
www.lowell.edu/Public/Info/Specials.html .
In addition to its Pluto research, Lowell Observatory has ongoing and
long-term programs to identify near-Earth asteroids, survey a region of
the solar system beyond Neptune known as the Kuiper Belt, conduct
decades-long research on the sun and sun-like stars, study comets,
search for extrasolar planets, and pursue a variety of astrophysical
investigations. The Observatory is also building the Discovery Channel
Telescope, a partnership with Discovery Communications that will
produce a versatile, powerful 4.2-meter telescope.
Lowell Observatory's mission is to pursue the study of astronomy,
especially the study of our solar system and its evolution; to conduct
pure research in astronomical phenomena; and to maintain quality public
education and outreach programs to bring the results of astronomical
research to the general public. The Observatory was founded in 1894.
Visit www.lowell.edu .
Respectfully, Roger L. Bagula
Lakeside,Ca 92040-2905,
URL : http://home.earthlink.net/~tftn
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