The head of NASA just reignited the debate over whether Pluto is a planet or not.
2006 first saw Pluto’s status come under serious fire when astronomers discovered a dwarf planet, Eris, on the outer edges of the solar system. The debate was recently reignited when the current head of Nasa, Jim Bridenstine, commented on the planets status at an event in August earlier this year. Bridenstine went on to say that Pluto is a planet in his view, telling reporters that they can ‘write that the NASA administrator declared Pluto as a planet once again’.
Bridnestine was confirmed as NASA’s administrator by close friend and president of the United States, Donald Trump, in April 2018. Considering this unusual route of placement, the nature of his direct comment undoubtedly reignited the debate between relevant specialists in the fields of astrology and science.
Backtracking to 2006, the debate first surfaced due to the discovery of Eris. This new-found dwarf planet was found to be 27 percent larger than Pluto, and three times the distance away from the Sun. With this in mind, it’s reasonable to understand why Pluto’s status was suddenly placed under fire. What is it that makes Pluto the superior as compared to Eris? Such questions encouraged the International Astronomical Union (IAU) to officially define that which constitutes a planet.
According to the IAU then, in order for a celestial object to qualify for the main title, it has to orbit the sun, it must be round in shape, and it must be able to clear it’s own orbital neighbourhood. Both Pluto and Eris did not meet the requirements, hence Pluto joined Eris under the title ‘dwarf’. In the case of Pluto, the planet under debate, failure to meet the final criteria is the reason it was not considered to be a true planet. ‘Clearing the neighbourhood’ means a planet has to cruise its orbit while either consuming or slinging away smaller objects. Pluto is only .007 times the mass of other objects in its turf, meaning it isn’t able to clear the neighbourhood properly.
Alan Stern, principal investigator for the New Horizons mission, which sent probes to investigate Pluto in 2015, said he is not in favour of the 2006 decision to remove Pluto’s planetary status. He criticised the criteria used to differentiate planet types as making no sense. Stern centres his argument on the fact that distance from the Sun effects the rate at which small objects in an orbit move, throwing the ‘clearing the neighbourhood’ criteria into question, and so, Pluto’s status. Stern declared the IAU’s ruling as ‘unscientific’, stating that the change was made to keep the number of official planets at a manageable number.
More than a decade has passed since the initial question was first thrown up into the air, and still, no definite label as been assigned to the ambiguous planet. What is clear, however, is that politics and opinion extend far beyond the Earth’s’ atmosphere.