NASA chief says 'Pluto is a planet' and claims the distant world should not have been demoted as he reignites a decade-long row

NASA administrator Jim Bridenstine has reasserted his belief that Pluto should be a classed as a planet and reignited a debate which has raged for more than a decade, the Daily Mail reports.

Astronomers and leading scientists have long squabbled over the issue of Pluto and its classification as a non-planet since its demotion in 2006.  

Mr Bridenstine stated in a recorded, but not broadcast, interview excerpt that he is still firmly of the belief that Pluto should be classed as a legitimate planet. 

'Just so you know, in my view, Pluto is a planet,' he said while on a tour of the Aerospace Engineering Sciences Building at the University of Colorado Boulder.

'You can write that the NASA Administrator declared Pluto a planet once again. I'm sticking by that, it's the way I learnt it, and I'm committed to it.'

It comes on the 13th anniversary of Pluto's fall from grace and formal demotion to a 'dwarf planet'. 

In 2006, the International Astronomical Union, a global group of astronomy experts, established a definition of a planet that required it to 'clear' its orbit, or in other words, be the largest gravitational force in its orbit.

The IAU used this to shake up the planetary world and remove Pluto from the ranks of the solar system's elite bodies, taking the number of planets down to nine. 

Since Neptune's gravity influences its neighbouring planet Pluto, and Pluto shares its orbit with frozen gases and objects in the Kuiper belt, that meant Pluto was out of planet status. 

But despite the official ruling, many have never accepted it. 

Mr Bridenstein is one of the die-hard supporters of Pluto and his latest remark backs this up.