Theories about an unknown planet hidden on the outskirts of the Solar System seem to be definitively disproved by NASA’s research. The case of the so-called “Planet X” dates back to the early 20th century, when the American astronomer Percival Lowell proposed the existence of such a body in order to explain some inexplicable features of the orbit of Uranus.
When Pluto was discovered in 1930, many astronomers rushed to celebrate the discovery of the infamous Planet X. But celebrations were premature, since it was finally found that Pluto was not big enough to explain the orbital anomalies of the outer planets. Today, most astronomers do not believe in the idea of an unknown planet in the Solar System, although the case of Lowell remains theoretically open.
The latest study, published in the journal «Astrophysical Journal», is based on data from the WISE infrared space telescope of NASA, which swept twice around the sky in 2010-2011 period, with an interval of six months between scans.
The researchers examined 750 million objects – stars, galaxies, asteroids, etc. – and looked for bodies that had been moved from the first scan to the second, indicating that they are relatively close to Earth.
The study concludes that there is no object of the size of Saturn or greater in distance up to 10,000 astronomical units. The researchers were able to further exclude a second, similar theory, according to which the Sun has a companion star which is located at a long distance and somehow remains unknown to this day.
The theory, which now has few supporters, was proposed to explain the supposed schedule of the asteroid attacks on Earth. The companion star is supposed to periodically approach the Sun and disturb the orbits of asteroids, sending some of them to the Earth.
Such a companion star or brown dwarf companion did not appear in the data provided by the WISE telescope. “The outer solar system does not seem to contain a small companion star or a gas giant planet,” is the conclusion of the study according to the author, Kevin Luhman of the Pennsylvania State University.
In a second study based on the data of WISE, a different research team announced the discovery of 3,525 stars and brown dwarfs located at a distance of up to 500 light years from Earth.
“Till now we did not know the neighborhood of the Sun as well as you would imagine,” says Ned Wright, principal investigator of the WISE mission.