Past IAU and Current IAU

About the IAU


*established 1919

* job to promote and safeguard science of astronomy

*established because a merger

*made up of 11,447 scientists from several different countries

Classifying Before Discovery of Dwarf Planets

Scientists classified planets by their colors, and the elements on them such as fire, earth, and air. Pluto was discovered in 1930 by Clyde Tombaugh. Pluto was originally called a planet, and was called a planet until 2003. In 1992, David Jewitt and Jane Law discovered that there was more than one thousand celestial bodies orbiting the Sun past Pluto. Further than Pluto, there was a larger solar system body known as Eris ( Discovered October 21, 2003 by Mike Brown, Chad Trujilo and David Rabinowitz). This discovery called for examination of how planets are described and classified. Ceres was also discovered, but Ceres was between Mars and Jupiter. All three of the new planets were about thirty times less massive than Mars.

New Classification

The IAU gathered in Prague to discuss what exactly Eris was, and whether the three newly discovered bodies were planets or not. The classifications that they came up with are as followed:

1. Must be in orbit around the Sun

2. Has sufficient mass to form spherical shape

3. Has cleared orbital path

They decided that Pluto, Ceres, and Eris only accomplished the first two points needed to be a planet. The other thousand bodies were known as Small Solar System Bodies (SSSB).

They agreed that these bodies only accomplished the first point needed.

Autobiography of Pluto: Not Needed Anymore

For as long as I can remember I was out there, alone, nobody knew me. The 8 other bigger planets in my family had all the fame, but most of all Earth. I despise Earth. Those pesty humans getting to decide who or what I am. Who gives them the right? I used to love humans, I was so famous to them! I even had a dog named after me on some cartoon show! For about ninety years I was the planet. And than it happened. My revolting brother, Eris was discovered. I remember that day. Eris, was always really mean to me. He was even colder than I was, yet he was a little bit larger than me. And he never let me hear the end of that. When he was discovered, the IAU decided to get together in Prague to discuss whether or not Eris was a planet like me and my eight brothers. I expected them to allow him to be a planet, as much as I would have hated that outcome. A day later I received the news. Eris would be classified as a dwarf planet. I was ecstatic! I did not even read further on the article. Later that day, all the planets were laughing, at Eris I assumed. Eris was crying and I tried to comfort him. He turned to me and said, " Thank you Pluto, I can't believe you're being this optimistic after this happened to us". I stopped and thought, "Where the other planets laughing at me"? I turned to Eris and said " I don't know what you mean", and he replied, "Pluto, you've been booted out"! And that was when my world turned upside down.
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