A Field Guide to Alien Planets

Countdowns
By Live Science Staff
published

Rogue planets

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Artist rendering of a planemo, or planetary mass object or rogue planet, surrounded by a disk of gas and dust that could form satellites. CREDIT: Jon Lomberg, www.jonlomberg.com

A rogue planet is a planet-sized object that has been ejected from its system and is no longer gravitationally bound to any star, so it orbits the galaxy directly. To become a rogue planet, a planetary-mass object would have to be ejected from its solar system, making it starless. This could be achieved by the competing gravitational forces of the sun and larger planets. Also known as interstellar planet, or orphan planet, a rogue planet would require geothermal activity in to sustain life without energy from a star.

Live Science Staff
Live Science Staff
For the science geek in everyone, Live Science offers a fascinating window into the natural and technological world, delivering comprehensive and compelling news and analysis on everything from dinosaur discoveries, archaeological finds and amazing animals to health, innovation and wearable technology. We aim to empower and inspire our readers with the tools needed to understand the world and appreciate its everyday awe.