Could this faint object be Planet Nine? Scientists find a 23-year-old infrared clue that may finally point toward the elusive world beyond Neptune

Scientists in Taiwan found a potential lead in the search for Planet Nine. Terry Long Phan and his team at National Tsing Hua University examined data from two older space surveys. They looked at images from the Infrared Astronomical Satellite in 1983. They compared those images with data from Japan’s AKARI satellite, which mapped the sky between 2006 and 2007.

The 23-year gap between the surveys gave the team enough time to spot slow movement. Objects in deep space move very slowly across the sky. Out of millions of signals, one object moved 47.46 arcminutes between the two surveys. That distance is small in the night sky. However, it shows clear movement over two decades.

Scientists narrow the Planet Nine search to one object

Standard optical telescopes cannot see objects that far out. Sunlight barely reaches 500 to 700 astronomical units away. One astronomical unit is the distance from Earth to the Sun. At hundreds of times that distance, sunlight is too weak to bounce back to Earth. Planets still release internal heat. Both satellites carried infrared detectors to capture heat radiation rather than visible sunlight.


The researchers filtered the survey data for specific traits. They searched for a body between seven and 17 times the mass of Earth. They started with 22 potential matches across both surveys. They cut that list down to 13, and finally to a single candidate. This object matched the heat and speed expected from a distant planet.

Astronomers suspected Planet Nine existed long before this discovery. They noticed unusual patterns among small, icy objects beyond Neptune. These distant bodies move in tilted, clustered orbits. They group together instead of spreading out evenly across space. A large gravitational force seems to be dragging them into alignment.

The new infrared candidate sits in the exact area predicted by those orbital patterns. If the candidate is real, its mass would explain the strange tilt of those distant ice worlds.

The researchers published their findings in the Publications of the Astronomical Society of Australia. They emphasized that the candidate is not a confirmed planet yet. It is simply a target that matches the expected physical traits.

The next step requires direct tracking from Earth. Phan noted that researchers will use the Dark Energy Camera on the 4-meter Blanco Telescope in Chile. They will search for the object at its calculated current position. This will show whether its movement matches the orbit required for Planet Nine.