Since the International Astronomical Union downgraded Pluto in 2006 to the new category of dwarf planets (at least nine, to date), our solar system has had eight known planets. But there would be a ninth, so far away that it has not yet been found: as big as five times the Earth, it would take about 10,000 years to make a complete turn around the Sun. Several scientific teams are looking for him, exposes this documentary, which makes their thirst for discovery communicative.
A very elliptical trajectory
In Arizona, astronomer Chad Trujillo estimates that this hypothetical planet would be at a distance of between 300 and 500 astronomical units (AU) from the Sun. Quite a trot: in comparison, the Earth is located only one AU from the Sun (150 million kilometers) and the most distant objects of our System were discovered at 120, then at 130 AU – the eighth planet , Neptune, peaks at 30 AU. Competitors or associates, several astronomers undertake to locate what they call Otne, extreme trans-Neptunian objects, which orbit well beyond Neptune, between 40 and 900 AU. To their credit, the detection of comets, moons of planets – more than 120 found around Jupiter and Saturn.
The sequel after the ad
But Planet 9 remains out of reach for now. Astronomer Konstantin Batygin suspects that due to its very elliptical trajectory, it would currently be farthest from the Sun, at 600 AU or more. It is also possible that it is hidden by the luminous background of the Milky Way. Planetologist Alessandro Morbidelli, from the Observatoire de la Côte d’Azur (Nice), explains that his discipline takes the place of archeology of the Solar System. Indeed, all this research at the ends of our world reveals its history to us. If it conforms to the hypotheses, Planet 9 would confirm the chaos of the early times of the Solar System. That’s what these Indiana Joneses of the universe are hoping to prove.
Saturday April 15 at 10:25 p.m. on Arte. Documentary by Florence Tran (2022). 55 mins. (Available in replay until June 13, 2023 on Arte.tv).
