Moon or Planet? The Exomoon Hunt Continues Artist Concept

Researchers have detected the first exomoon candidate -- a moon orbiting a planet that lies outside our solar system. Using a technique called microlensing, they observed what could be either a moon and a planet -- or a planet and a star.

Researchers have detected the first exomoon candidate -- a moon orbiting a planet that lies outside our solar system. Using a technique called microlensing, they observed what could be either a moon and a planet -- or a planet and a star.