Meet 'Ammonite': A newly discovered icy object beyond Pluto

Technology Jul 25, 2025

Meet Ammonite—an icy, far-off object just found beyond Pluto by Japan's Subaru Telescope.
Spotted as part of the FOSSIL survey and announced in Nature Astronomy, Ammonite is only the fourth known "sednoid"—a rare group of space rocks with super-elongated orbits way past Neptune.

Ammonite's orbit doesn't fit what scientists expected from Planet Nine theory

Here's the twist: Ammonite's orbit doesn't fit what scientists expected from the popular Planet Nine theory, which suggests a hidden giant planet shapes these distant orbits.
Instead, Ammonite swings out in almost the opposite direction compared to others.
Researchers say this could shake up what we think we know about our solar system's edge—and they're hoping upcoming telescopes like Chile's Rubin Observatory will help unravel the mystery.