Why are there only 8 planets in our solar system?

Earlier there were 9 planets in our solar system. But due to new definition of planets , which was given by IAU( international Astronomical union society) in August 2006. According to Resolution B5 . read more

That’s is we have only 8 planets in our solar system.Now Pluto has been kept in Trans-Neptunian Objects .But that doesn’t mean that this number will be constant .It can change because nature has not set any criteria for planet, this is in our hand. read more

The other answer is that once there were a gazillion planet-like things in the solar system, which collided and combined, and the 8 known planets (plus dozens of dwarf planets, 100+ moons, several belts of gravel and possibly one or two planets that we haven’t discovered yet) are what’s left from that time. read more

Ceres is a planet, and our solar system does not have only 8 planets, at least according to the equally legitimate geophysical planet definition. 19th century astronomers did not know that Ceres is in hydrostatic equilibrium and therefore a complex world that doesn’t belong in the category of asteroids and comets. read more