As a result, it is sometimes called the Öpik-Oort cloud. For More on the Oort Cloud:An Asteroid is About to Embark on a Very Long Voyage to Interstellar SpaceDwarf Planet FarFarOut is Further Than Anything We've Seen in Our Solar SystemOver Time, Some Stars Get Uncomfortably Close to ...
Astronomers wonder, though, whether there might not really be a ninth planet previously undiscovered but lurking in the outer reaches of the solar system, perhaps in the giant Oort cloud of objects that begins hundreds of astronomical units (au) from the Sun and extends outward. Evidence Supp...