Astronomers are gathering in the Czech capital, Prague, hoping to define exactly what counts as a planet. The International Astronomical Union (IAU) hopes to settle the question of Pluto, which was first spotted in 1930.

Experts are divided over whether Pluto – further away and considerably smaller than the eight other planets in our Solar System – deserves the title.

The stakes were raised when a bigger planet-type body, known as 2003 UB313, was discovered by a US astronomer.

Any decision to downgrade Pluto would send shockwaves through the scientific community, instantly outdate textbooks, and change how the basics of the Solar System are taught in schools.

There are suggestions the scientists could decide to include Pluto in a new classification system that marks it out as different to the eight larger planets.

Via: BBC News