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New Celestial Object 'Ammonite' Challenges Planet Nine Theories

7/20/2025

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Summary

Story summary

Astronomers have unveiled a fascinating new celestial object, dubbed "Ammonite," lurking beyond Neptune. This sednoid, measuring between 220-380 kilometers, boasts an orbit that raises questions about the elusive "Planet Nine." Discovered with the Subaru Telescope, Ammonite is thought to be over 4.5 billion years old, shedding light on the ancient mysteries of our solar system.

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Story summary

Astronomers have unveiled a fascinating new celestial object, dubbed "Ammonite," lurking beyond Neptune. This sednoid, measuring between 220-380 kilometers, boasts an orbit that raises questions about the elusive "Planet Nine." Discovered with the Subaru Telescope, Ammonite is thought to be over 4.5 billion years old, shedding light on the ancient mysteries of our solar system.