Assignment 4

The Changing Pluto

       The most detailed view to the date of  the ensure surface of the dwarf planet Pluto,

                                   by NASA Hubble Space Telescope took from 2002 to 2003.(1)   

         Pluto is a dwarf planet which is once considered as the ninth planet of the solar system. Its diameter is 2368 km, mass is about (1.305*10)^22 kilograms. Pluto locates in Kupier belt,  a shadowy disk-like zone beyond the orbit of Neptune populated by a trillium or more comets.(1)
It is primary made of ice and rocks and is relatively small, about 1/6 the mass and 1/3 the volume of Moon. Pluto's orbit is highly eccentric, distance between the Sun and Pluto is about 4.4 billium kilograms when is closest to the Sun, and it became 7.3 billium kilograms when Pluto is far from the Sun.(2) The average temperature on Pluto is roughly minus 225 degrees C. but because of it eccentric orbit, the temperature on Pluto also changes dramatically depends on its location, when Pluto is moving closer to the Sun, its thin, tenuous atmosphere expands; when Pluto is moving far away from the Sun, the atmosphere collapse. Pluto has 5 known moons, Charon, Nix, Hydra, Kerberos and Styx which was found in 1978, 2005, 2011, 2012 respectively.(3)

 

                               

Pluto and its five moons(2)

      The discovery of Pluto is largely due to 2 person, Percival Lowell and Clyde Tombaugh.

      Percival Lowell was born on March 13, 1855, in Boston. He entered Harvard University and graduated in 1876 with a Bachelor degree of Arts in Mathematics. After graduation, he worked in his family's textile business. In 1882, He served as a foreign secretary to the Korean special mission. In 1890s, Lowell learned the discovery of canals on Mars by Italian astronomer Giovanni Schiaparelli, which attracts Lowell's excitement, he built an observatory on Mars Hill in 1894 in order to prepare for Martian opposition, that is Lowell Observatory. Despite he insist on that canals exist on Mars and claims he found several pictures about it, his insistence was disproved by NASA in 1972. In 1905, Lowell put the work in searching for the missing planet. He calculated that the variations in the orbit of Neptune and Uranus were caused by a ninth planet, which he dubbed Planet X. However, he didn't really discover Pluto. On Nov, 12, 1916, Lowell died of a cerebral hemorrhage. But his Laboratory continued the search, and 24 years later, Clyde Tombaugh, an astronomer of Lowell Laboratory, found Pluto depends on Lowell's calculation.(4)

                                  Image of Percival Lowell, founder of Lowell Laboratory and the person greatly 
                                          the discovery Pluto.(4)

      Clyde Tombaugh, who was born in 1906 in Streator, Illinois. He build his own telescope by himself in 1926, and built another 2 in the next two years. He used his telescope to observe Mars and Jupiter and sent the drawings of them to Lowell Observatory. The astronomers in Lowell was impressed by the power of observation of Clyde, they invited him to work at the Observatory. He stayed at Lowell Observatory for nearly 14 years. In 1932, he entered the university of Kansas and got Bachelor degree of Science in 1936. In 1938, he earned his master's degree in 1938 and returned to Lowell Observatory as a full-time astronomer. During his time in Lowell Observatory, he discovered hundreds of new variable stars, asteroids and counted over 29000 galaxies. He worked at Lowell until being called to service during World War 2. After the war, Lowell Observatory unable to rehire him due to a funding shortfall. He then worked for the military at the ballistics research laboratories of the White Sands Missile Range in Las Cruces, New Mexico. He left the missile range in 1955 and being awarded the medal of the Pioneers of White Sands Missile Range. He entered the faculty of New Mexico State University in Las Cruces until retired in 1973. He died in 1997, shortly before his 91th birthday at his home in Las Cruces, New Mexico.(5)

Clyde Tombaugh, the discoverer of planet Pluto(5)

     When Pluto was found in 1930, astronomers considered that Pluto was a big planet with a huge mass and size. However in 1978, as Pluto's moon Charon was found, astronomers was able to found the mass and size of Pluto. Pluto's mass is only 0.0021 mass of the Earths, its diameter is 2368km, despite Pluto's tiny size, astronomers believe that it is larger than any other planets pass the orbit of Neptune. Over the last few decades, with powerful new ground and space-based observations, astronomers realized Pluto is only a big example of a collection object named Kupier Belt. Astronomers found other objects in Kupier Belt which size is similar to Pluto. In 2005, Eris, an object in Kupier Belt which mass is 25% more than Pluto, and its diameter is about 2600 km- 200 longer than Pluto's. The foundation of Eris pushed the concept that solar system has nine planets began to fall apart. During the 26th General Assembly of the International Astronomical Union, which held from August 14 to August 26th, 2006 in Prague, Czech Republic, IAU redefine the definition of Planets in solar system:
      (1)It needs to be in orbit around the Sun.
      (2)It needs to have enough gravity to pull itself into spherical shape.
      (3)It needs to have "cleared the neighbourhood" of its orbit.
Because Pluto doesn't match the third one, IAU moved Pluto down to the new classification-"dwarf planet".(6)

Examples of Plutinos(6)

      Plutinos , means "little Plutos", is a generic name of the class of Kupier Belt members with orbits that very close or even cross the orbit of Neptune. Despite the close distance between the orbits of Plutinos and Neptune, Plutinos will not encounter Neptune. The orbital periods of Plutonis compared to Neotune's are in the ratio about 2 small numbers.(7)

References

     (1)Charles Q. Choi, Dwarf Plant Pluto: Facts About the Icy Former Planet, Nov 03, 2014. Purch http://www.space.com/43-pluto-the-ninth-planet-that-was-a-dwarf.html
     (2)Karl Tate, Pluto's 5 Moons Explained: How They Measure Up (Infographic), July 11, 2012 SPACE.com,
http://www.space.com/16538-pluto-moons-explained-infographic.html
     (3)Solar System Exploration,
http://solarsystem.nasa.gov/planets/profile.cfm?Object=Pluto
     (4)Nola Tayler Red, Percival Lowell Biography, Feb 13, 2013, SPACE.com, 
http://www.space.com/19774-percival-lowell-biography.html
     (5)Clyde Tombaugh Biography, Dec 10, 2013, Academy of Achievement,
http://www.achievement.org/autodoc/page/tom0bio-1
     (6)Fraser Cain, Why Pluto is No Longer a Planet, Jan 5, 2012, Universe Today,
http://www.universetoday.com/13573/why-pluto-is-no-longer-a-planet/
     (7)Plutinos, June 6, 1997, SKY & TELESCOPE NEWS BULLETIN,
http://carlkop.home.xs4all.nl/plutino.html