why is planet sedma not concidered as the tenth planet?

Answer 1

Because there are still arguments whether Pluto is actually a planet, "Sedna" is larger than Pluto. But I believe the argument stems from sheer distance from the Sun, it is more of a rogue body.

Answer 2

If it was considered as such, we could say there are 50,000 planets in the Solar System. Sedna is one of many Pluto-sized objects that rotate around the outer edge of the Solar System. There is Quaroar, Midna, and others like it.

The true tenth planet is Xena, a massive celestial body that rotates even farther outside the Solar System then Sedna and the Plutinos. Recently discovered, it is about the size of Mercury.

Answer 3

astronomers are trying to define the word planet, but it isn't easy. many favor the reclassification of the bodies in the solar system into three groups: the rocky terrestrials, the gas giants, and the ice dwarfs. there are hundreds of known ice dwarfs including pluto, quaoar, sedna, 2002 EL61, and 2003 UB313 (the official name of xena), and 2003 UB313 is about five percent bigger than pluto. this is called the kuiper belt, pluto was the first kuiper belt object discovered.

http://en.wikipedia.org/wiki/Kuiper_belt

Answer 4

I DIDN'T EVEN KNOW THERE WAS A PLANET CALLED SEDMA

Answer 5

its too small?

Answer 6

its too small...