NASA's Wide-Field Infrared Survey Explorer (WISE) has been unable to find the large, unknown planet referred to by astronomers as "Planet X".
NASA researchers have suggested that Planet X exists in our solar system beyond the orbit of Pluto, according to Nature World News. However, astronomers have found no evidence of the planet after searching through hundreds of millions of celestial objects. Despite not finding the planet, astronomers were able to find a huge amount of stars.
The data from WISE covered the entire sky in infrared light, but no object was found close to the size of Saturn within a 10,000 astronomical unit (au) distance, and no planet close to the size of Jupiter was found within a 26,000 au distance. The researchers said that Earth is one au from the sun, while Pluto is about 40 au from the sun, RedOrbit reported.
The theories that support the idea of Planet X suggest that the planet is huge, Nature World News reported. Kevin Luhman, associate professor at Penn State University for the Center for Exoplanets and Habitable Worlds, said the planets beyond Pluto were not like the theories suggested.
"The outer solar system probably does not contain a large gas giant planet, or a small, companion star," Luhman said.
Although WISE was unable to find the mysterious planet, a second study from the Astrophysical Journal reported that the telescope found 3,525 new stars and brown dwarfs within 500 light-years of the sun. A total of 762 of these stars had also been discovered as part of the Luhman study, according to RedOrbit.
"We're find objects that were totally overlooked before," said Davy Kirkpatrick, lead author of the study and member of the NASA Infrared and Processing Analysis Center at the California Institute of Technology.
Kirkpatrick worked with researchers who used WISE in 2010 and 2011 to capture images of about 750 million stars, asteroids and galaxies, RedOrbit reported. The telescope was reactivated in 2013 and renamed NEOWISE in order to help scientists find and learn about asteroids and other objects that posed a threat to Earth.
Ned Wright, professor at the University of California, Los Angeles, said that although the researchers were unable to find Planet X, they still had the opportunity to make more discoveries in outer space, RedOrbit reported.
"We think there are even more stars out there left to find with WISE," Wright said. "We don't know our own sun's backyard as well as you might think."
