Pluto

Pluto once considered a planet, has now been classified as a trans-Neptunian object. Since 2006 astronomers have referred to Pluto as this. It has generated wonder, with recent discoveries about its composition. When Eris was discovered the definition of planet had to be adjusted. These discoveries resulted in the development of a new term: dwarf planet. Pluto lost its status as the ninth planet of the solar system. It was discovered in 1930 by Clyde Tombaugh. Pluto and Eris are located in the Kuiper Belt. They are not the only trans-Neptunian objects present in the area. Other objects include Orcus, Quaor, Haumea, Makemake, and Sedna. The universe is much larger than previously thought. There is still much to learn about dwarf planets in our solar system.  

      The International Astronomical Union developed the term dwarf planet. The definition of this term is "a body that orbits the Sun and is massive enough for its gravity to have pulled it into a spherical shape, but not so massive that it has cleared the region around its orbit of smaller bodies." This has generated controversy within the scientific community. Some astronomers felt that the new term was simply created without enough understanding about the nature of Pluto. Classification can be difficult when there may be other objects so radically different. This change demonstrates that science does need constant revision. It is constantly evolving and experimenting. Another term has emerged for objects beyond Neptune. Plutoids are dwarf planets past the planet Neptune and the term officially came into use in 2008 by the IAU. Eventually, classification systems will have to be expanded to accommodate new objects discovered.

         

       
        The atmosphere of  Pluto differs from that of the Jovian planets. The atmosphere could methane and nitrogen. The dwarf  planet contains possibly contains a rock core. Considering it is far from the sun, temperatures are low. This atmosphere may not always be in a constant state. There are shifts. When Pluto gets close to the sun the planet only forms a thin atmosphere. where there is water there could be life. However, this may not be higher order life forms, but microorganisms. Assuming evolution functions in the same manner, the possibilities are endless. It has been confirmed by NASA that the atmosphere does contain immense amounts of nitrogen gas. The mystery is why there is so much. Only further investigation can allow for complete answers.
           Pluto's orbit is extremely elliptical. It has a far distance to go when revolving around the sun. It takes approximately 248.54 years for Pluto to circle the Sun. This means that one Earth day would be the equivalent of  6 days and 9 hours.Pluto actually does cross the orbit path of Neptune. This only happens every 20 years. Pluto is unusual in the sense that its axial tilt is only 17 degrees. Charon a satellite of Pluto follows a circular path around the Kuiper Belt object. The plane is inclined at 118 degrees in the Pluto-Charon system. Gravity also effects both Pluto and Charon. Being so close results in tidal bulge activity on both objects. This could serve an important purpose. The force acts as a control on the rotational velocity of both objects. Pluto has three moons besides Charon.These moons include Nix, Hydra, and P4. They are fairly recent discoveries which occurred in the 2000s.

      

Seeing as Pluto and Charon are so inseparable they are classified as one system. Other moons are not as vitally linked. The Hubble Space Telescope was helpful at gathering information in regards to Pluto and Charon. The information gathered allowed for a more accurate estimation of the mass of Pluto. It has been recorded as 0.0021 Earth masses. Closes examination of orbits can reveal much about this object. 

        So far, there are general basic units of information that astronomers have found on Pluto. The dwarf planet's perihelion is 4.1 light hours. The aphelion is 6.8 light hours. Pluto size is smaller than the Earth's moon. The diameter is 2,325 km to 2,274 km. The mean surface temperature is about -230 degrees Celsius. This is a very cold place covered in ice. The cloudtop gravity is about 0.06 g. More will be revealed in the future as astronomers explore deeper into space. 

References 

Mcmillan, Steve and Chaisson, Eric. Astronomy. New York : Pearson Education INC, 2007. 

Fressin, Francois.  30 Second Astronomy. New York: Metro Books, 2014.

Couper, Heather and Henbest Nigel. The Space Atlas. Milan: Gulliver Books, 1992.