Some of us may still remember the mnemonic we learned in school to remember the order of the planets in the solar system: “But will you come and eat Thursday on a clean tablecloth?”we repeated over and over to put Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto in order. Then, Pluto disappeared. In 2006, the International Astronomical Union considered that this star did not meet the criteria to be a planet in its own right – “a spherical body in a quasi-circular orbit around the Sun and having cleaned the surroundings of its orbit of any body likely to be found there”.
Despite this disappointment, astronomers do not despair of finding a ninth planet in our solar system. For many years, the precision of telescopes prevented the discovery of this possible very distant star. But that could soon change, reports Scientific American. A new telescope will soon be put into service in Chile, at the Vera C. Rubin Observatory. Scientists have a lot of hope in him.
To find a ninth planet, we need to look beyond the Kuiper Belt
“In the first two years [de fonctionnement du télescope]we will be able to answer this question, [y a-t-il une neuvième planète]”, assures Megan Schwamb, Northern Irish astronomer. To do this, it will be necessary to successfully probe what is happening behind the Kuiper belt, the set of astral bodies in orbit, located after Neptune and of which Pluto is a part, relegated to a dwarf planet.
In 2004, Mike Brown, one of the astronomers who realized that Pluto was not a real planet, discovered a very distant object beyond the Kuiper Belt. With his colleagues, they called him Sedna. This celestial object is the first OTNE, extreme trans-Neptunian objects, to have been detected by scientists. Since then, dozens of other bodies have been seen beyond Neptune. Their existence suggests that another planet could be hiding somewhere out there.
The orbit of several celestial objects intrigues scientists
What intrigues astronomers is the trajectory and the force exerted on these OTNEs. If they were only pushed by the force emanating from Neptune, they would not follow such an orbit around the Sun, specialists think. For them, another planet, smaller than Neptune must therefore be responsible for these forces.
Mike Brown and his colleagues believe that the ninth planet, still unknown and hidden if it exists, is ten times heavier than Earth and is 700 astronomical units (AU) away, knowing that one AU is the distance from Earth and the Sun, approximately 150 million kilometers. The three-ton telescope installed in Chile last May and which will come into operation at the beginning of 2025, is therefore the greatest chance to put an end to hypotheses and speculations and to finally see if a ninth planet appears. invites you to dinner.
