Answer: Sedna

Sedna is one of the more curious objects to call our solar system home. The minor planet, roughly half the size of Earth’s Moon and just slightly smaller than Pluto, is a trans-Neptunian object–an object that orbits our Sun at a greater average distance than Neptune. Such objects are fascinating in and of themselves, but even among such extreme travelers, Sedna is an anomaly.

The fastest orbital pattern in the solar system belongs to Mercury, which orbits the sun in a speedy 88 days. Earth orbits the sun once every 365 days. Even slow-poke Pluto, which takes a whopping 248 Earth years to orbit the sun looks like a race horse in comparison to our trans-Neptunian traveler. Sedna’s extremely elliptical orbit carries it over 30 times farther from the Sun than Neptune and takes an astounding 12,050 Earth years to complete.