Wow, awesome find. It's a double planet with the heavier one being quite dense while the lighter one is quite puffy, making it be considered a moon by SE despite being bigger. It reminds me of Proxima Centauri's first planet, which is bigger than its sun.
this really boggles my mind...how is this possible?
Usually this happens when 2 astroids start orbiting together in a "Dance" around its parent star (Usually this only happens at the edge of a solar system near the outer belt) i believe? You can see this with pluto. its moon is almost the same size as the planet.
Aliens, heh. Who would've thought? One day were Causing wars and another day were finding earths!
Also, asteroids are unlikely to start orbiting each other. Pluto is a dwarf planet and Charon is closer to that as well. It is possible for multiple asteroids to share an orbit if they have the same origin, but even when very far away from the system's barrycenter, asteroids don't have enough mass to get in a stable orbit around eachother. It's theoretically possible, but very unlikely.