Transcript Pluto: To be or not to be?

Pluto, UB313, and VB12 (Sedna)
A little bit about Pluto:
Part of the Kuiper Belt (region of frozen
objects beyond Neptune)
Considered ice dwarf
Orbit is eccentric compared to other planets:
A little bit about UB313:
Discovered in 2003
Roughly about 2x the size of Pluto
97 AU’s from sun
Surfaced with
methane ice like
Pluto
A little bit about Sedna (VB12):
Extremely elliptical orbit
¾ size of Pluto
NOT a Kuiper Belt Object
Definition of a planet?
 There is no REAL definition of what a planet is…
Purely historical. Mercury, Venus, Earth, Mars, Jupiter,
Saturn, Uranus, Neptune, and Pluto are planets. Nothing else in
the solar system is a planet.
Historical plus. Mercury through Pluto are planets, as is any
newly discovered object larger than Pluto.
Gravitational rounding. Any object which is round due to its
own gravitational pull and which directly orbits the sun is called a
planet.
Population classification. Just like the solar system very
naturally divides itself between round objects and non-round
objects, it also very naturally divides itself between solitary
individuals and members of large populations.
Bibliography
http://www.space.com/scienceastronomy/0
50729_new_planet.html
http://www.gps.caltech.edu/~mbrown/sedn
a/#planets
http://en.wikipedia.org/wiki/Pluto_(planet)