<ul><li>Planetary-mass objects (PMOs) are mysterious, unattached objects in space that have puzzled astronomers.</li><li>Previously believed to be failed stars or ejected planets, new research shows that PMOs form through interactions between young stars and their gas disks.</li><li>The powerful gravitational forces between disks cause gas to collapse into dense filaments and break apart into smaller gas clouds, which can reach a critical mass and become PMOs.</li><li>Unlike planets, PMOs move in sync with stars in their birth cluster and can potentially have their own moons or smaller planets.</li></ul>

Rogue planets: Born from chaos in young star clusters

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