Could there be more than one planet outside the Kuiper belt?

And Planet X could roam as far as 600 to 1200 AU, well beyond the Kuiper belt, the region of small icy worlds that begins at Neptune's edge about 30 AU. read more

For more than 7 decades, everyone thought Pluto to be a planet since its discovery in 1930. On comparison of perigees of Pluto and the recently hypothesised planet 9, the former is in our neighbourhood. read more

Two more dwarf planets, Haumea and Makemake, were discovered in the Kuiper Belt in 2008. But Haumea's status as a dwarf planet may be in doubt. In 2017, when the object passed between Earth and a bright star, scientists realized it is more elongated than round. read more

If this model is accurate, it would imply the existence of a second Kuiper Belt, farther out and more massive than the one we already know about. Madigan said: We should have a new Kuiper Belt that’s far more massive than the current-day Kuiper Belt, at larger distances, and preferentially lifted off the plane of the major planets. read more