Hope you all know that the 9th Planet Pluto is no more. It’s not gone though , just changed it's status and name. Pluto became 134340. After 76 yrs of being as a planet Pluto fails to comply the redefinition of Planet.
As per IAU (Internationl Astronomical Union) resolution passed on Aug’24 2006 a Planet
a) must be in orbit around the Sun
b) must be massive enough to be a sphere by its own gravitational force. More specifically, its own gravity should pull it into a shape of hydrostatic equilibrium.
c) Must have cleared the neighbourhood around its orbit.
And Pluto fails the third criteria. So IAU gave dwarf planet title to Pluto. A dwarf planet should match the below criteria
a ) Orbit around the Sun
b) Has sufficient mass for its self –gravity to overcome rigid body forces so that it assumes a of hydrostatic equilibrium shape.
c) Has not cleared the neighbourhood around its orbit
d) Not a satellite of a planet or other nonstellar body
Pluto is not been visited by any Spacecraft. NASA launched
New Horizon in 2006 , which if all goes well will reach Pluto around 2015. Pluto has a satellite, Charon which has been named as a mythological figure who ferried the dead across. Now it's time to ask for your marks if you forgot to mention Pluto as a part of Solar System in your school days :-)
