The search for Planet Nine

A recent story about an older study

The October 2026 news story discusses a scientific paper published in May 2025. The later date of the popular article is not the date of a fresh planetary discovery. Researchers found a possible lead in archival infrared sky surveys. It deserves follow-up, but there is still no confirmed ninth major planet in the Solar System. [1–3]

What did IRAS and AKARI show?

The team compared IRAS observations from 1983 with AKARI data from 2006. One promising pair of catalogue sources might represent the same distant body. Their positions are separated by about 47.5 arcminutes, but two positions cannot yet establish a reliable orbit or even prove the two detections are one object. The suggested range of 7 to 17 Earth masses and 500 to 700 astronomical units was part of the search model. These are not independent measurements of a newly found planet. [3]

Why is the search difficult?

A very distant object is extremely faint in reflected sunlight. Its internal heat might help it stand out in infrared light, but the signal depends on its size, temperature and composition. Earth’s movement also causes parallax: an apparent shift that must be distinguished from the body’s own orbital motion. The authors proposed further observations, including with the optical DECam instrument. Their paper does not report that such observations have already confirmed the candidate. [3–5]

History and the test ahead

Uranus was spotted in 1781 and at first mistaken for a comet. Neptune was found in 1846 near a position predicted from irregularities in Uranus’s motion. Pluto was identified in 1930 by comparing photographic plates. In 2006 it was classified as a dwarf planet because it does not dominate its orbital neighbourhood. [6–12] The 2016 Planet Nine hypothesis aims to explain the paths of some distant bodies beyond Neptune. Survey biases, new discoveries and competing analyses still matter. Convincing confirmation would require repeat sightings and an orbit that predicts where the body will be found next. [13–20]

Read the complete article in Serbian: https://naukazamlade.com/sr/svemir/potraga-za-devetom-planetom/