2,500 odd scientists meet in Prague for the International Astronomical Union’s (IAU) general assembly, and rejected a proposal that would have seen Pluto retain its status as a proper planet.
Instead, Pluto has now been re-classed as one of the smaller ‘Dwarf Planets’. Which mean it will probably have to be removed from all those nice wall charts in the school class rooms around the world!
But why has it been demoted?
Even though Pluto was smaller than some of the moons in the Solar System, it was still the biggest known object in the Kuiper Belt, which allowed it the status of planet.
Then in 2003, UB313 was discovered, and found to be 3,00km (1,864 miles) in diameter, making it a little larger than Pluto.
So instead of making UB313 another planet – both have now been classed “plutons” (Pluto-like objects), or to put it another way – icy “Dwarf Planets”.