

A new study from #PrincetonU's @TheAmirSiraj shows that there may be rogue planets the size of Mars existing in the outer solar system, captured by our sun's gravity long ago. https://t.co/erqX085ju1 (via @physorg_com)
— Princeton University (@Princeton) January 5, 2024
Smaller than Earth but larger than Mercury, #PrincetonU's @TheAmirSiraj and colleagues may have discovered a hidden planet orbiting 100-200 times farther from the Sun than Earth — Planet Y. https://t.co/cwlewVUc5c
— Princeton University (@Princeton) August 25, 2025