Dear steemians. Today I want to share about Resolution 5A of the IAU General Assembly on the status of Pluto.

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When studying science in elementary school first, we are asked teachers to memorize the name of the planet in the solar system. Almost all students are able to memorize in accordance with the order of proximity of the planet to the sun. Including the author himself is still memorized to date. Mercury-Venus-Earth-Mars-Jupiter-Saturn-Uranus-Neptune-Pluto. There are nine planets that surround the sun. The sequence of planets is very well memorized in the minds of students. There are nine planets that surround the sun.

Year 2006 happened very shocking event of science world especially field of Astronomy. In the General Assembly of the International Astronomical Union (IAU) in Prague, the Czech Republic is a very historic event in the world of Astronomy. The incident is removing Pluto's status from the list of planets of the Solar System. This means starting in 2006 Pluto is no longer a planet. Why is that?

The 2006 IAU General Assembly turned out to redefine the notion of the planet. Resolution 5A of the 26th IAU General Assembly contains the new definition. In the resolution stated, a celestial body can be called a planet when it meets three conditions, is orbiting the Sun, large enough to keep the shape round, and has a clear or "clear" orbital path (no other celestial bodies in the orbit). Source

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After the demotion of Pluto into dwarf planets, science books and Astronomy have to be revised again. Thus, the number of planets that surround the sun is reduced to eight planets. The decision has been a debate for astronomers for years. With the discovery of the number of other celestial objects that are the size or larger and have characteristics similar to Pluto, the debate is increasingly fierce. If Pluto is preserved as a planet, then celestial bodies such as Ceres, Charon and some other celestial bodies must bear the status of a planet as well. The most logical step is to lower the rank of Pluto into dwarf planets.

There are several reasons why Pluto is removed from the planet list. The reasons are as follows.

1. The orbit of Pluto around the sun is so skewed that it cuts the orbit of the planet Neptune so that as it surrounds the Sun the planet Pluto is in a position very close to the sun than the planet Neptune.
2. Pluto size is more sophisticated than other planets. Even the size of Pluto is almost the same as other celestial bodies such as asteroid ceres and Charon.
3. The orbital path of Pluto that cuts off the orbit of the planet Neptune makes its orbit path unclean. While the orbit of the planet must be clean and no other celestial bodies in the orbit.
4. The composition of Pluto is chemically more cometary than the planet. Different characteristics compared to other planets are found after the development of increasingly sophisticated telescopes and increasing space research.

Kuiper belt of the current group of Pluto

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Pluto is further incorporated into the Kuiper Belt group. This Kuiper belt is an area outside the orbit of Neptune up to 50 AU from the sun. The beginning of Pluto expenditure from planetary status occurs an emotional reaction from fans. This is very reasonable, because Pluto is the youngest planet at the time. Nevertheless, we must realistically accept the fact. Technological developments sometimes find new theories that the old theory undergoes significant improvements. So it is with Pluto.

Reference

1. http://kanansukses.blogspot.co.id/2012/02/alasan-pluto-dikeluarkan-dari-tata.html
2. http://oalamagz.blogspot.co.id/2011/07/untuk-waktu-yang-lama-pluto-dipercaya.html
3. http://kanansukses.blogspot.co.id/2012/02/alasan-pluto-dikeluarkan-dari-tata.html
4. https://www.mataangkasa.com/kenapa-membunuh-pluto-diartikan-tata-ulang-tata-surya/

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