Down to eight planets.
Pluto was kicked out! I'm sure it'll all leave a terrible scorch mark upon your minds.
Okay, seriously, this is MAJOR scientific news. At the rythm at which we discovered new small planetoids similar in size to Pluto, we'd have ended up with over a hundred planets in our solar system within a year or two. Ridiculous
SO they decided to redifine the word "planet" AND they introduced a new term, that being "dwarf planet".
A "planet" (1) is a celestial body that: (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighbourhood around its orbit.
A "dwarf planet" is a celestial body that: (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape (2), (c) has not cleared the neighbourhood around its orbit, and (d) is not a satellite.
All other objects (3) orbiting the Sun shall be referred to collectively as "Small Solar System Bodies".
Pluto was kicked out! I'm sure it'll all leave a terrible scorch mark upon your minds.
Okay, seriously, this is MAJOR scientific news. At the rythm at which we discovered new small planetoids similar in size to Pluto, we'd have ended up with over a hundred planets in our solar system within a year or two. Ridiculous
SO they decided to redifine the word "planet" AND they introduced a new term, that being "dwarf planet".
A "planet" (1) is a celestial body that: (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighbourhood around its orbit.
A "dwarf planet" is a celestial body that: (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape (2), (c) has not cleared the neighbourhood around its orbit, and (d) is not a satellite.
All other objects (3) orbiting the Sun shall be referred to collectively as "Small Solar System Bodies".