Discovery: The brightest planet in the universe

American scientists believe they have discovered a new dwarf planet at the edge of the solar system.

Named OF201, this object measures around 700 kilometres in diameter (three times smaller than Pluto) and is currently three times further from Earth than Neptune.

With an absolute magnitude between 3 and 4, it may be one of the brightest objects in the solar system. Its discovery was officially announced by the Minor Planet Center of the International Astronomical Union on 21 May 2025.

The researchers are now requesting time to direct the James Webb, Hubble and Alma telescopes towards their discovery. 

A 23-year-old amateur astronomer from California, Sam Deen, had already managed to track the candidate dwarf planet in old database records.

"OF201 is, in my opinion, probably one of the most interesting discoveries in the outer solar system in a decade," he stated.

(MH with MaSi – Source: Cité de l'espace; Photo: © Unsplash)