Now that /sci/ is jizzing itself over Musk's triumph yesterday, I thought we should take the time to discuss a recent mystery that has largely been forgotten.

The official proposal that the bizarrely chaotic orbits of some Kuiper Belt Objects like Sedna can be explained by a very large unseen object orbiting at 800-1500 AU disrupting their orbits. Estimates of the object's mass range from 6-10 earth masses (by comparison, Uranus and Neptune have 14 and 17 Earth masses, respectively). The object may have a thick gaseous envelope or even have a more traditional thinner atmosphere which the surface is visible underneath.

What is /sci's/ take on this? According to Wikipedia, if it indeed is exists, a probe can potentially reach it in as little as 20 years.