In the new paper, which the scientists plan to put forward to the IAU, the current definition is described as "technically flawed" - it only recognises planets as objects that are orbiting our Sun and not other stars. It also says the need for zone-clearing means "no planet in our Solar System" meets the criteria for planets.

The authors argue the new definition is "geophysical" and based on the physics of the world itself.

So e.g. if the positions of Earth and Pluto were swapped, the Earth would no longer be a planet according to the IAU's definition.