WHAT is Sedna? Is it a planet? A planetoid? Or even a comet? The most distant object so far spotted in our solar system and the largest since Pluto made its debut in 1930 has reopened the controversy over what should and should not be named a planet.
Tentatively named after an Inuit goddess of the ocean, Sedna is nearly as big as Pluto and takes a massive 12,000 years to orbit the sun. Mike Brown, the Caltech planetary scientist whose group discovered it, thinks it comes from the Oort cloud of comets that extends halfway to the nearest star.…
