Astronomers find no signs of Planet Nine
A team of astronomers, who scoured about 87 percent of the southern sky, has yet to find any trace of Planet Nine in our solar system.
Discovered in January 1930, Pluto was formerly known as Planet Nine. However in 2006, astronomers reclassified Pluto as a dwarf planet.
While astronomers suspect that there may be a previously unknown Planet 9 in the distant Solar System, new searches at millimeter wavelengths have failed to find any reliable candidates.
Led by Sigurd Ness of the Institute for Theoretical Astrophysics at the University of Oslo, astronomers detected the planet using data from the 6-meter Atacama Cosmology Telescope (ACT) in Chile.
Although ACT was designed to study the cosmic microwave background radiation, its relatively high angular resolution and sensitivity make it suitable for this type of exploration.
"The search found a number of potential candidate sources (about 3,500 of them), but none could be confirmed and no statistically significant was identified," the team said in a statement.
According to estimates, the speculative "Planet 9", would be about 5–10 Earth-mass in size and orbit around 400–800 AU from the Sun.