Discovering a Cosmic ‘Fossil’: What Astronomers Found at the Edge of Our Solar System and Its Implications for ‘Planet 9’

Astronomers have made an exciting discovery: a new celestial body beyond Pluto’s orbit, named 2023 KQ14. Its unusual path hints that if there is a “Planet Nine,” it could be far from the sun or might have been ejected from our solar system entirely.

Also called “Ammonite,” this object falls into the category of “sednoids.” Sednoids are distant bodies known for their highly elongated orbits. Unlike most planets, which have more circular paths, sednoids travel in very stretched trajectories. For 2023 KQ14, its closest point to the sun is about 71 times farther than Earth is from the sun. It’s estimated to be between 136 and 236 miles wide, making it significantly larger than Mount Everest.

This is only the fourth known sednoid. While its orbit differs from the others, it has been stable for around 4.5 billion years. The research team, using the Subaru Telescope, suspected that all four sednoids had similar orbits about 4.2 billion years ago. Something must have happened at the solar system’s edge around that time, changing their paths.

The peculiar orbit of 2023 KQ14 indicates greater complexity in the outer solar system. This finding also raises questions about the existence of the elusive “Planet Nine.” Yukun Huang, the project leader, pointed out that the current orbit of 2023 KQ14 suggests that the Planet Nine hypothesis may be less likely. It’s possible that a former planet was expelled from the solar system, leading to the different orbits we now observe.

2023 KQ14 was first detected in multiple observations through the Subaru Telescope in Hawaii across several months in 2023. Follow-up observations later confirmed its existence. This data, combined with records from other observatories, helped astronomers trace its movements for nearly 19 years.

Looking ahead, experts see the need to uncover more about celestial bodies like 2023 KQ14. Fumi Yoshida, another member of the research team, emphasized that understanding these distant objects can shed light on the solar system’s history. The findings were published in the journal Nature Astronomy on July 14.

This discovery not only excites scientists but also captivates those interested in space. Recent surveys show many people are fascinated by the solar system’s mysteries, often discussing them on social media. Engaging conversations and shared curiosity could inspire more discoveries in the future.

For more details, check out the research from the [National Astronomical Observatory of Japan](https://www.nao.ac.jp/en/news/science/2025/20250715-subaru.html).

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