OF201 is incredibly lightweight on a cosmic scale. Scientists estimate its mass is about 20,000 times less than Earth’s and ...

OF201 spends only 1% of its orbital time close enough to us to be detectable. The presence of this single object suggests ...

The discovery challenges the Planet Nine hypothesis, which suggests a massive, unseen planet is influencing the orbits of distant TNOs. While most extreme TNOs show a clustered pattern that supports ...