Astronomers who surveyed 87 percent of the sky said they had not found Planet Nine yet in the solar system.
Astronomers named Pluto, discovered in January 1930, as the Planet Nine. They did, however, reclassify the celestial body as a dwarf planet.
While astronomers believe that the solar system contains a previously unknown Planet 9, the new search yielded no results.
Researchers uploaded the study, "The Atacama Cosmology Telescope: A Search for Planet 9," in The Astrophysical Journal.
Astronomers Can't Find Planet Nine Yet Again
Astronomers used data from Chile's six-meter Atacama Cosmology Telescope (ACT) to track the planet.
While ACT is designed to study cosmic microwave background radiation, its high angular resolution and sensitivity make it ideal for this sort of search.
For six years, astronomers studied about 87 percent of the sky from the southern hemisphere. They used multiple ways to analyze the photos to discover faint sources while sacrificing positional information.
"Their search found many tentative candidate sources - about 3,500 of them - but none could be confirmed," the Harvard-Smithsonian Center for Astrophysics, a participating institution in the research, said in a release on March 11.
They added: "There were no statistically significant detections."
Where is Planet Nine?
According to Gizmodo, the team is 95 percent certain that the new scan will not find a solar system object with the given search properties inside the studied area.
No one knows where Planet Nine is in the sky or if it even exists. Still, its gravitational impact requires it to be within particular limits. The imaginary planet is traveling at the exact moment and in specific directions.
Hence, researchers assume that Planet Nine might be hiding in the solar system's beyond reaches, possibly in the Oort cloud of debris hundreds of astronomical units distant from the Sun.
According to experts, planet Nine would have a mass of five to ten Earth masses and circle the Sun at a distance of 400 to 800 au.
With new telescopes, like the Vera Rubin Observatory in Chile, set to go online in the near future, astronomers may finally have the instruments they need to identify something small and far away. Planet Nine's reality can only be hidden for so long.
History of Planet Nine
Astronomers initially started looking for Planet Nine in 2016, Live Science reported. It was 10 years after Pluto was demoted to a dwarf planet from its position as the solar system's ninth planet.
Many teams have attempted and failed to discover that fictional universe half a decade later. The greatest challenge in the search for Planet Nine is the sheer length of the journey.
That implies normal visible light telescopes have a slim chance of finding the chilly, dark Planet Nine. Instead, astronomers use telescopes like the ACT, which can scan the universe using millimeter wavelengths, a short type of radio wave similar to infrared light.
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