We only recently discovered that there is a tenth planet in our solar system. Now it has been discovered that there is a moon orbiting this planet. Both planet and moon are far away from the sun and other planets, which is why there has long been controversy about whether this is actually a planet or merely an asteroid that got caught in our solar system’s gravitational pull. The existence of the moon gives credence to astronomers who believe we have a tenth planet.
The moon was discovered in September with the use of the Keck II telescope. The tenth planet is not officially a planet yet and has not been named. It’s still known by its designation 2003UB313.