Lonely Planetoid

When I was a kid (not so long ago) I was taught that there where nine planets. We were all probably good in memorizing the names when we were in elementary schools. But not alot of us needed to keep remembering and updating after we got the names correct in our grade three science periodic exams. It's a surprise that, not so young pinoys when asked, many would still say that there are nine planets.

Over the past few years new science have completely changed previous the understanding of the outer Solar System leading to the discovery of  Kuiper belt objects (like Eris in 2005), further out than the orbit of Pluto.

Due to the discovery of these objects a debate came to a head in 2006 with an IAU resolution that created an official definition for the term "planet". According to this resolution, there are three main conditions for an object to be considered a 'planet':

1. It needs to be in orbit around the Sun – All original nine planets does this.

2. It needs to have enough gravity to pull itself into a spherical shape – All original nine planets passed this.

3. It needs to have “cleared the neighborhood” of its orbit – little Pluto failed this one.

In the end, astronomers voted for the controversial decision of demoting Pluto (and Eris) down to the newly created classification of “dwarf planet”.

Last July, Pluto again made news when NASA's Hubble Space Telescope took pictures of four moons orbiting the distant icy dwarf planet Pluto.

We all love Pluto and even more to some, like the man who created this Pluto song.