A Field Guide to Alien Planets
Get the world’s most fascinating discoveries delivered straight to your inbox.
You are now subscribed
Your newsletter sign-up was successful
Want to add more newsletters?
Delivered Daily
Daily Newsletter
Sign up for the latest discoveries, groundbreaking research and fascinating breakthroughs that impact you and the wider world direct to your inbox.
Once a week
Life's Little Mysteries
Feed your curiosity with an exclusive mystery every week, solved with science and delivered direct to your inbox before it's seen anywhere else.
Once a week
How It Works
Sign up to our free science & technology newsletter for your weekly fix of fascinating articles, quick quizzes, amazing images, and more
Delivered daily
Space.com Newsletter
Breaking space news, the latest updates on rocket launches, skywatching events and more!
Once a month
Watch This Space
Sign up to our monthly entertainment newsletter to keep up with all our coverage of the latest sci-fi and space movies, tv shows, games and books.
Once a week
Night Sky This Week
Discover this week's must-see night sky events, moon phases, and stunning astrophotos. Sign up for our skywatching newsletter and explore the universe with us!
Join the club
Get full access to premium articles, exclusive features and a growing list of member rewards.
Rogue planets
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.
Get the world’s most fascinating discoveries delivered straight to your inbox.

